I am seriously considering swapping out my carbd '86 stock 305 to a 350. the 305 i have now is running shitty and it needs valve seals and the intake gasket replaced which is gonna run me around 400 bucks just to get it running decent again.

There's a local shop nearby my house with a guy that has a completely rebuilt chevy 350 bored 40 over with 454 hp

he's asking 1000 for the engine and another 500 to put it in, and i can sell the 305 now and make a little money back. does that sound like a good deal? what problems could we potentially run into with this swap? any tips or advice would be great as i am a first time car owner

what kind of mpg could i expect with the new motor with normal driving habits?

 

Great, 450 HP for $1000. Nice claim, but where's the supporting evidence? Dyno sheet? Stack of receipts? Have you heard it run? Why is it for sale? What heads does it have?
If it really is a 350 making that much HP, then it's got a fairly serious cam in it, so forget great MPG. In fact, if you have stock LG4 gearing, then probably forget using OD.
MPG can break into the 20s with that HP with EFI, but I wouldn't expect you to average any better than mid-teens.
If your car is an automatic, do you have a loose enough torque converter for that much cam? Probably not.
Not to kill your hopes, just to give fair perspective.
Also, valve seals and intake gaskets on your 305; you can do yourself for under $100.

 

I was referred to the shop by a close friend of mine who has known the owner of the shop for some time now and puts his trust into his work so if I cant trust them then I cant really trust anyone. As far as the claim for the hp, he did have it on a dyno 8 months ago when he was going to use it for a project car but sold the car and it's been in the corner of the shop ever since. He's got 1000 into the engine so he's just looking to get back what he had into it so it's not some craigslist ad thats full of crap.

I could do valve seals by myself but I have neither the tools, the mechanical know-how or the space and time to do the seals. So if I want them done right it's going to be around 400 bucks but that also includes replacing my distributor and having it timed.

A few weeks ago I also had coolant spewing from my passenger side valve cover and I'm just tired of the problems with the stock engine that doesn't even seem worth the time and repairs (money) when i can upgrade to a 350 and get a lot more hp. and lately my mpg's been around 10 and less than 10 so i would be extactic with mid teens.

as far as the torque converter, how much of a problem could that be with the 350?

 

450hp 350cid engine is a pretty tall claim - I've seen $10,000 350 drag race only motors not make 450hp. I'd say 450hp is not a reality - no matter whom you trust. It's not necessarily that anyone is outright lying, but that they just might not know themselves.

Want to trust in someone ... trust in us here at TGO - it really really takes ALOT more than $1000 into any 350 motor to get 450hp - the heads alone to make that kinda power would be well over $2000

 

no doubt i trust in the folks here on tgo, but how many guys on here are actually auto mechanics? not too many. I'm not saying I don't trust what people have to say on here but it could be possible that this 350 does have over 400 horses from a guy who works on cars for a living. im sure the $1000 price doesn't include his labor hours as he most likely rebuilt it himself unless he got a wicked deal somewhere else. But I am brand new to cars and all this so I'm learning as I go.

I am talking to the guy again tomorrow morning and hopefully I will get some more info regarding the engine. If you guys don't think this is legit, what type of questions should I ask? s

 

defiantly ask for a parts list, cam card, what the heads are, casting numbers or manufacturer, aluminum or iron heads, ect. 450 is a lot from a 350, and 1000 will not cover the cost of parts, so this guy is either giving it away, or is full of it.

 

.040 over means that engine had some serious bore issues that wouldn't clean up at the standard .030.Really no room for any other rebuilds.

A bit of advise...............Don't assume there isn't many full-time mechanics on this site.

 

I dont trust most mechanics. The vast majority of people here do most of their own work and understand these cars better than most mechanics do. I will guarantee you most of us wouldn't be wasting $400 having a "mechanic" replace an intake gasket and 8 valve seals (exh valves don't see any suction, so no point in wasting time on them). Most mechanics nowadays have no clue how to make our cars run. We drive some of those transitional 1980-1990 era fuel injected cars. Primitive and outdated, the old school hot rod mechanics are better dealing with carburetors, and new-school guys are better at dealing with OBDII based stuff. The average GM dealership mechanic would scratch his head trying to troubleshoot a TPI system these days and just resort to throwing parts at them. So dont get too hung up on "mechanics". They may be good at what they do, but chances are that 3rd gen camaros are not "what they do".

A 450hp 350 sounds like a pretty tall tale. You can trust all you want, but you need to VERIFY. Frankly if your car is otherwise stock, even if it did make 450hp it would be an awful experience trying to make it work for you, whether you're messing with the fuel injection to get it to run properly or struggling to drive it around because it has such a frustrating power band.

We will be glad to help you figure out whether this thing is really capable of "454hp", but you're gonna need to do some homework and go look at it and check it out and come back to us with block casting numbers, camshaft specs, and head casting numbers etc. If "454" hp is a legit number then those few pieces of info will corroborate. Horsepower is affected by induction + heads + cam with a smattering of cubic inches for flavor.

gonna agree with not wasting money on a block that's already .040 over. If this thing goes south on you, you'll need to do this all over again.


Just get your intake gasket fixed - leaky valve seals aren't going to blow up your motor. They're not a big deal.

 

^^You have some pretty consistent comments there. Like everyone said, 450hp is an empty statement without supporting evidence. $1500 is damn near standard rebuild cost with maybe a cam upgrade at best. Someone trustworthy will be willing to show you everything about it because they have nothing to hide.

I've been around MANY different kinds of 'mechanics' in my time thus far. Calling yourself a mechanic is one thing, actually knowing what your doing is another. The only way to find someone who is truly skilled at working on cars is to see examples of their work.

 

The guy at the shop whose got the engine knows old chevys and carbd engines more than most. My friend who referred me to the shop used to work on old chevys years ago and talks with the shop owner all the time and the owner tells him no one knows older cars and chevys better than this guy. I realize that there are a lot of mechanics that are untrustworthy and try and rip people off but this shop has a much higher reputation

But more about the engine. That much HP wouldn't work well with a stock third gen?

 

If you're not gonna listen to our advice then why are you asking us for it?

It's VERY EASY to find out everything you need to know if you get information on

1. What heads does it have
-Are they GM or are they aftermarket brand?
-what's the casting number
-aluminum or iron
2. What cam does it have
-Brand
-Roller or flat tappet
-hydraulic or solid lifters
-Duration at .001 inch lift, and duration at .050 lift for intake and exhaust sides
-Lobe separation angle
- OR JUST GET A BRAND/GRIND NUMBER and skip all the BS above.
3. What induction does it have
-Carburetor?
-TPI?
-Single or dual-plane intake?

Emphasis is on 1 and 2, but 3 has major implications on practicality and convenience in regards to both the engine swap and getting it running afterwards. Plus it's never gonna make the same power with a 305 TPI system on top of it as it would with a big holley 4 barrel and a single plane intake, but that's not gonna make for the most streetable car.

Find out those 3 things and come back to us and we will be able to tell you most of what you need to know.

We can tell you just from those things:
1. Likely power levels
2. How streetable it is
3. How well it will put up with crappy gears and a stock torque converter
4. whether it's worth the money

There's a whole lot more to an engine than a random horsepower number. Generally the cheaper the engine and the higher the horsepower the less practical it's going to be. There's no shame in asking those questions - they will think you're a guy who knows what the hell he's doing if you ask those things. From there they can either be a-holes and try to mislead you and jerk you around in which case there are shenanigans afoot, or they will tell you exactly what you need to know with no drama.

So again, find out the details and we can all give you good advice. But if you dont care what we tell you, then just buy it.

And for the record a healthy 350 will make 1hp and 1tq per cubic inch. That's with a large roller cam and Vortec heads you can pull that off, and Vortec heads are probably the best sbc cylinder heads chevy ever made. To do better than that by 100hp you are gonna need cylinder heads that are at least $1500 for the pair, and that's what they want for that whole motor. Add in a decent roller cam and valvetrain and you're gonna be at $2k just in cam and heads. Something doesn't add up. The only way that can be true is if this is a used engine, not a freshly assembled rebuild. Just the fact that they said "rebuilt" makes me think twice about it making anywhere north of 300hp. "Rebuilt" usually means a 70s truck motor with a crappy edelbrock cam that makes 170hp on a good day. Hell maybe they'll hook you up with some "camelhumps" or "202"s and you'll hit 180hp on a good day. If you hear "202" or "camelhumps" just pass on it. If it's got "202"s or "camelhumps" on it there is no way it's making 450hp and they're lying to you about that - so who knows what else they're lying to you about.

If these guys are legit, they know what parts are on that thing and they will tell you all about it and be impressed you know the right questions to ask.

 

If someone was good at porting Vortec heads themselves, it should be possible. I got my Vortecs for under $100 / pr at the local salvage yard. David Vizard showed how to get 447 HP from a budget 350, using a 224/224-108 HR cam with 1.6:1 rockers for 0.560" lift.
Figure $200 for the used '87-up short block assembly, $250 for an RPM AirGap,$300 for the cam, et cetera, it should be possible to get this HP for this money.
If you do have a 450 HP 350, then figure a Summit 2200-2400 stall converter is gonna add about $250 to your final bill. I wouldn't use anything less for stall RPM with a mystery cam capable of 450 HP in a 350.
And you'll soon want a 3.73:1 posi rear, but a 2.73:1 could get you by for a while.
Further reinforcing the HP situation, on one side of the fence, there are several builds with Vortec 350s and Comp XE268H cams in the 370 HP range, but a few years back CHP and Moore did a HOT-cammed Vortec 350 that did over 418 HP on a dyno.

 

My xe262 cammed Vortec 350 is definitely not in the 370hp range. That cam is barely smaller than a 268... wish I knew what the trick was there! Its a fun little 350 though I think it's only making around 300 to the rear wheels. What's that... 330 to the flywheel? 450 at the flywheel is a good bit beyond that.

Also they claimed "rebuilt". Just machinework will likely eat up at least $500. All the work you mentioned in addition to the machine work will end up eating up the vast majority of that budget... and this is an engine a shop is selling, implicitly for a profit. I just dont see how $1500 is doable in that context.

BUT..... you got any details about that David Vizard vortec build? 224/224 hydraulic roller cam? Makes me want to do a cam swap.... But apparently vortecs in stock form stall in flow above around .500 lift.

 

ok thanks guys I def appreciate all the input and I am listening but I'm just giving my input as well. I'm stopping by the shop tomorrow to have a talk with the guys there and I will hopefully get some more info. I am pretty sure the engine was used and rebuilt but I don't know. I've got some homework to do before I get any further into this thread

The 350 is carb'd with a holley set up btw. and right now i'm not so worried about fuel efficiency because right now i'm getting barely 10 mpgs with the set up i have now

 

and the shop isn't selling the motor for profit, it's one mechanic who had a side project and ended up selling the car so he's still got the motor he was going to use for it. The sale and the swap wouldn't be through the shop for a profit

 

Now it's coming together a little bit. Sounds better to me.

You need to find out what heads and cam it has and you'll be able to figure out all you need to know!

Once something is assembled like that, you never really get your money back out of all the parts. I dont think I could get $800 for my engine, and I've got at least $2500 in it and 20k miles on it.

 

I think he realizes that you don't get everything out of what you put into it which is always how it is with cars. It sounds like he's had multiple projects over the years and this engine could be a compilation of a few projects. When I first brought my car to the shop, he liked the fact that a kid like me (I'm only 19) is interested in classic cars and fixing my own problems and he def prefers working on classics. The swap would be a side job, like on a weekend if i went through with it but like i said i have some hw to do.

 

Save some $$$$ and fix your 305. You will need the extra $$$$ for other improvements and repairs for your car down the road. Trust me on this one.

 

getting my 305 fixed is still not out of my mind but the thrill of driving a suped up 350 is very tempting. Say I do get the 305 fixed and running decent again its still a 400 dollar job which includes taking the shitty boat distributor off, yea that's right, it's got a boat distributor on it. That seems like a good deal for valve seals because ive searched and seen people being quoted over 1000 bucks for just valve seals from a repair shop.

I feel like between my timing, crappy carb situation, and other gasket problems that are arising I would be better off with a fresh 350 and again that's if the work done to it warrants laying down the cash for it. My car has no power right now and eats gas like no other so constant repairs and parts are gonna end up costing me more than this 350 swap which again is assuming it runs well and doesn't need any work

1500 - 400 (valve seals & other repairs i didnt have to spend ) so 1100 with the engine and not the seals. and minus whatever I could sell my engine for and the other parts that go with it. its got a brand new alternator and water pump on it. I figure if I get out for less than a grand and the engine ends up being worth it then I made out pretty well. ...and again ive gotta figure out how good this engine really is so hopefully by tomorrow we will have a better idea

 

Im 39yrs old. I've been swinging wrenches since I was 6 or so. I've been making money doing it since i was 14.. sometimes fulltime sometimes for fun. carry on! I'm just one of many on this site!

 

There's no good excuse for any mild 305 being under 20 MPG in a third gen. Well, a TH350 and 4.10:1 gears might do it.
Something is badly wrong, besides just valve seals. It may well be the marine dizzy, if it has no vacuum advance.

 

A couple of points.

1. Valve seals are not a "if you dont fix it your engine will blow up" kind of issue. They are not a big deal in the vast majority of cases. You can do it yourself in a weekend if you want, several methods of doing it, but it's just not worth the trouble. If valve seals are bad you're better off just waiting for a new engine.

2. Dont count on getting ANYTHING out of your 305.

See if your 305 is healthy by doing the various vacuum tests (Get a $20 diagnostics vac gauge from a parts store.) and compression tests on it.

And Im gonna be completely honest... if you've got a carb and you cant change the intake manifold gaskets, how do you plan to do an engine swap? you think it's hard getting your 305 to run right, just wait til you have to get into properly tuning an aftermarket 350 and fixing all the irritating issues that invariably pop up with engine swaps. It will cost you a lot more than just the price of the motor. Also depending on the specs of the motor it may still be an absolute pain in the *** to drive in your car. You may be in DIRE need of a stall converter and gears.

 

its also got a carter afb comp series and would be a lot better off with a q-jet.
the one thing that has delayed having the seals done was finding a stock distributor for it, and now the option of the 350 swap came up and sounded like a good idea to me. Even the fact page on tgo says the 1986 lg4 was the "armpit" of the entire engine run. might as well get something i can be proud of

 

well i would have the guy do the engine swap and i would help out and learn a little. i wouldnt take on the task of the engine swap alone

the bad valve seals are in cylinders one and seven and evey couple of weeks the plugs need to be replaced because they are charred from burning oil. its smokey on start up but it also smoke when i drive it, not as bad but i can smell it. i also need to fill up my oil every week or so. could be more than just a valve seal problem?

 

Sounds like you got some worn rings to me. That's why I suggested doing a leakdown test. REALLY bad valve seals and real worn valve guides will smoke really bad on deceleration with the throttle closed (very high vacuum - will pull oil through the intake valve guide). If it doesnt smoke especially bad then, then valve seals arent the whole problem.

 

That whole situation just sounds sketchy to me. I've seen the whole "450hp" advertisement ONE too many times.. and 90% of the time it's nowhere near that mark and they are just hustling a sale. My 355 is making right at that power and I've got a LOT more tied into my motor than that and I've gotten some insane deals on parts. If you'de like to see how much I've spent on it I'd be more than happy to get my receipts book out to show you what to expect.

 

yeah that sounds a lot more like the problem I'm having.

 

Okay I've got an update about the motor today. I stopped by the shop and got some more info on it. Here's a little background on it... The motor was originally owned by a guy down in south carolina. He originally had it in an old police cruiser (think it was an old cutlass) and he had big *** tires on it, like 26s i believe. The guy drove it up to rochester and ended up wanting a bigger motor with over 500 hp. The engine has less than 1000 miles on it. The guy at the shop bought it for 500 bucks because that's all he would pay for it and the guy took it because he wasn't concerned much with getting money out of it. The mechanic who I know that bought the motor spent 400 on a new chrome intake and another 300 for the carb because he was going to use it on a project car but ended up selling the car so now's he's got the motor sitting there. That's where his 1k investment comes in. Since buying the motor he's redone all new seals and gaskets as well as the new intake
. The original owner probably had thousands of dollars into the motor

It's got iron GM heads bored 40 over

the casting number is 462624

engine number is 3970014

He wasn't too sure about the cam it has but he said it's a pretty big cam but will still work for my car. it's got Hydraulic lifters

The intake is a chrome edelbrock air gap with a holley carb on top. I think it's a holley 0607 with electric choke

seems like a pretty good deal for me at the moment and to do away with my crap 305

 

and as far as the claim for the hp, he really doesn't know but he said it's pushing 400. as far as im concerned i really don't care if it's got that much hp, I just want something with more power than what i've got

 

400HP with those heads? Yeahh, no. Those heads are trash. Even if they were completely ported they'd still be junk. Old 70's Flat tappet block which is fine. Did he even tell you if it was a 2 or 4 bolt main? I'm assuming you didn't look?

I can tell you right now that motor doesn't have anywhere near "thousands" invested into it. That's a VERY basic worked over 350. How does he know if that cam will work for your car if he doesn't even know what it is? There's all kinds of red flags here. Sounds to me like he's trying to take advantage of you because he knows you don't know anything about wrenching.

 

I knew it! 624 heads. THE. WORST. EVER.
They don't flow well, they always crack sooner or later, they have bad chambers, they won't do 400 HP with any cam, they're thin castings.
PASS! And change mechanics AND machine shops. So much for them being trustworthy.

 

Yep. I agree. Stay far, FAR away.

 

couldn't i eventually just upgrade to better heads?

 

You're completely missing the point. It's not about the heads.. it's the fact this guy is jerking you around and you still want to buy **** from him. Why? If he really is a mechanic he KNOWS that motor isn't making anywhere near 400HP. If he's willing to lie about something stupid like that, what makes you think the rest of the motor is legit? That and your other information is just all over the place.

 

LOL @ heads. This thread was amusing...

 

the guy he bought the engine in the first place probably jerked him around telling him it had that much hp and then he never bothered to look up the numbers

 

If you dont want to listen to people who know, then just go buy it anyway.

Think about it... with your high regard for these "mechanics"... why would we all be able to immediately tell you how awful that motor is, and these mechanics are excused because they "didnt run the numbers"? Fact is we either know more than your mechanic or he's trying to take advantage of people, so give us a little credit.

Theres a chance the block and rotating assembly are fine, but there's no telling. You're playing roulette. It's a crappy 70s 350 that's bored over so far you wont be able to rebuild it again, and they threw a shiny intake on it and probably some garbage old school 60s era cam.

It probably makes as much horsepower as your 305 did when it was healthy.

I'd almost suggest you buy the block cheap as a rebuildable core with a potentially decent rotating assembly, but it's still .040 over. If you needed to rebuild it you'd have to go .060 over, and I and a lot of other people here can tell you that's real risky. I wouldnt pay more than a few hundred for it, if they were honest I'd trust it more and say $500. There's a reason the other guy wasnt willing to spend more than $500 on it - because it's not worth more than $500. A shiny intake doesnt change that.

If you want to buy it for $1500 and then buy new heads..... just buy new heads for your 305 if you think valve seals are the problem. 081s are probably $200 a pair at most. You might be able to get em for free since no one wants 305 heads. If you REALLy want to get something done on the cheap, go buy a 305 Lb9 engine from someone that swapped to a crappy 350, probably like the one that guy is trying to sell you. 305's are boat anchors to most people - you can get them REAL cheap. You'll just have to find someone who is willing to sell a 305 and not pretend it's a 350. A 305 TPI engine makes 200hp - that's as much as some big block V8's during the era those 624 heads are from.

 

HE IS A MECHANIC. How many people do you think do that in the auto world to make a quick buck?? A lot. Screwing people over with car parts is about the easiest way to make large amounts of money fast. It takes literally two minutes to find out all that information about that motor as far as casting numbers are concerned. If he was that negligent - you REALLY want him working on your car when he's that bad with his own stuff? Use your head man, this isn't math here.. this is common sense.

 

He's more of less in denial right now, which is understandable. We all want to believe we are getting this great deal on an insane motor, when the reality is, the people they thought were trustworthy are not, and called out upon by mere strangers. (Those of which you don't trust necessarily).

 

yet another

fresh
rebuilt
strong


engine which has no documentation to confirm the claims and is just another typical piece of junk like most out there.

It's going to cost you some $$$ to do it correctly.

 

Sabresfan, listen to these guys. I'm 19 as well but I've been poking cars with wrenches since I could walk...those guys are no good. Just because there is a Holley carb on it doesn't mean squat, there are FORD MOTOR HOMES that came with Holleys. Better question, what all is included? Is there an HEI distributer on it and ready to go? I'd tell you $1k at the very most if you could hear it run. Being a mechanic he would know exactly what camshaft was in the motor he planned to put in his toy.

 

If your building from scratch, lose the 305, its a boat anchor. It always pays to build the biggest motor you can afford. By-the-way, you mentioned "coolant coming out of valve covers", could be real bad.

 

I appreciate the help with this guys. I decided to blow off the swap and just sell the car. I'm leaving for school in a few weeks anyway and I didn't want it to sit around, seemed like a more sensible choice. The guy at the shop was a dick to me anyway so I didn't want any part of that, screw him. I am brand new to cars and all this so it helps to hear opinions from people who know their stuff, thanks guys. My dad has a rusted old '72 chevy pick-up w/ a 350 out back behind his business so i think i'm going to pull that and rebuild it when I get home for winter break so I can learn a thing or 2

 

Sorry to see you leave the thirdgen scene, dont stay away forever.

When you get some money and want to work on somethig as a long term project car - do a thirdgen LS1 car.

Also, those 72 Chevy trucks are GORGEOUS. I've always loved that generation of Chevy truck.

 

I wouldn't say I'm leaving the thirdgen scene, just taking a break. And actually I've got my eye on a more original iroc that's for sale near me so depending on how fast i sell mine I might go buy another one

 

Never underestimate the advice of those who know what they are talking about. Good luck!

 

I can't help but ask you this question.I just noticed your location.Is that Roch,NY??.If so,tell me the name/address of this guy that builds engines.I might want to pay him a visit.................

 

I am in rochester. The guy doesn't build engines, he does projects on the side. I really don't want my name caught up in all of this, depending on what you meant by pay him a visit

 

Any time a guy gets burned,it makes honest people's advise harder.Trust in the fact your name would never come up.