supermaxxbasher

I have a 350 with those crappy 882 heads on it with like 7.5-8:1 compression..My step dad has a set of 305 heads off of his 1981 chevy truck and he said that he would give me them if I could use them .They are the small combustion chamber heads also..What I want to know is if I have them ported and bigger valves put in them will they work on my 350 which is out of a 1979 blazer..I know they will raise my compression pretty good I just want to know if they are better then those 882 heads. Oh and i don't know the numbers on the 305 heads either..sorry..

Sitting Bull

Sure they will work--bolt right on! Boost your compression to something around 9 to 1 too

Post the casting number for us so we can advise you further. It's an eight digit number cast into the top of the head, between the springs.

Check the link at the end of my sig for the lowdown on exactly what you want to do

supermaxxbasher

hey thanks man I will get the numbers when I can..Good that will put me right at the compression I want too..

supermaxxbasher

ok here are the numbers I pulled off of it...

Cast number=14022601

someother number=H130

heads have 1.84 intake, 1.5 exhaust valves

58cc combustion chambers

Will these heads work good on my 350 with those 882 heads on it..

Sitting Bull

Yup. Same heads I have.

Just port and polish them according to my instructions and you'll be laughing. 1.94" intake valves are a hot ticket for them, too.

supermaxxbasher

hey thanks man

supermaxxbasher

would it hurt my engine if I put those heads on my engine without porting them cause I don't have the time nor the resources to do the porting...I can get for mainly nothing and I think there better than those 882 heads as it is...So again would it hurt it..

Sitting Bull

No, it will work fine.

blacksheep-1

I am in the same situation, thanks for the info.

supermaxxbasher

alright I am gonna have them ported cause I dont want to have to fight with pulling the heads again!..How much Hp can I expect if I port and have bigger valves put in them..along with my raised compression to around 9.5:1

8Mike9

Not cost effective if you're paying to have the port work done.

I only mention this because you say "have them ported", which leads me to believe you won't be doing the work yourself.

supermaxxbasher

I don't have the tools to do it...I am only 17...and I don't have the talent to port something cause I know I will most definitly screw something up..lol.

Motor City Mike

I'm going to say to stick with a 350 (4" bore) cylinder head. I actually don't think you will make any more power, even though you'll have higher compression, ported heads, and bigger valves. The reason is because of the small chambers in the 305 heads, which shroud the valves and restrict air flow in 4" bore engines. This is even more of a problem with bigger valves, and any port work performed to increase flow won't be realized. If you want to really make these heads work, open up the chambers to your bore size, but if you're going to go through all that trouble, you may as well start out with some good 350 castings to begin with.

Sitting Bull

Nonsense!

You CAN do this work, it is NOT rocket science. Get busy and read the thread I posted for you. It tells you just about everything you need to know, and you can get help from almost any one of us for what you don't.

Rent the die grinder and cough up about $30 for carbide cutters and get busy!

F-BIRD'88

All this is speculation and totally untrue.

You have no actual experience with these heads.

Get a set, rebuild and Port them. Install 350sized valves and then get them flow tested. The deshrouding nessessary to the chamber is actually quite minor. Then bolt them on your 350. And go for a ride.
Good bang for the $$$'s ...

A nice $low buck$ way to wake up a 350 with 882 heads.

Any body can do this that is willing to put in the effort.

The chamber is simular in shape to a Corvette aluminum L-98 head.

Finished chamber size can be made to be anywhere from 50cc to 65cc.

Streetiron85

If you don't want to rent a die grinder, you can try an electric drill. I know... it's a cheap shortcut... but with a sharp carbide bit, you can make some noticable progress, and at least get your feet wet (not literally... bad idea when using electric tools)
Porting is something that takes a while, once you get going you don't want to quit til it's primo.
I'm just trying to get you hooked

Motor City Mike

At this point, I'm just going to ignore F-BIRD'88's response. I stand firm on what I have previously said. I guess if he's happy with his port job on his heads, then I guess that's all that really matters. If you're going to put the time/money with porting and bigger valves, don't discount those 882's. While they're not the best factory iron heads out there, they still have a lot of potential. I did a quick search and came up with an ARTICLE where they compared stock 882 heads with the same heads that were only pocket ported and 2.02/1.60 valves installed, on a "mild" build 350. With that change alone, the engine made 37 horsepower. If you want to increase compression, this also can be easily/cheaply done while the heads are at the machine shop.

Sitting Bull

You are virtually alone in your opinion on the 882 heads. Almost every one of the really experienced guys here--and F-Bird'88 sits amongst them--HATE the 882 heads. They will also tell you the 305 heads, with a decent home port and polish, are very nice indeed.

Not trying to start any flame war but F-Bird'88 has helped TONS of people on this forum and is respected.

You, on the other hand, are new. It is perhaps best to get the lay of the land first before offering critical comments, isn't it?

F-BIRD'88

Well if you care to really read the article the motor picked up a big 26 peak hp from 285 to 311.

I get the results much more like you'd expect from bolting on the Edelbrock performer heads shown in test 3 . 285 to 340hp.
On this level of motor. More on a more radical motor.
Cause they flow that much air.

If you want to go to a lot of bother to pick up 20hp or so,
then modify your 882's.

If you'd like to double those results for the same $$$ ,then modify a set of 416's or 081's as per mine and others guidelines from past posts.

The most you'll safely flat mill off an 882 is .060" or .070"
which will get you to about 69cc's from 76.

On a typical dished piston 350 the compression ratio will still be too low.
You could angle mill them but the cost is prohibitive and beyond a budget oriented build up.
Starting with the small chamber head is best.

Yes 305 heads flow less than a 350head in stock form.
because the stock valve is smaller.
Once ported they actually improve a lot more than a 882 head will. The added compression ratio available from the smaller 58cc chamber is another plus.
Its easy to tweek the chamber volume to your likeing with deshrouding and or flat milling. A range of 50cc to 65cc's finished chamber volume is easily obtained.
Most of the chamber enlarging gets done anyways just to fit the larger valves.

These heads are generally a little better casting than the late lightweight 882/624 casting.

If you'd like a 76cc 350 smog head that isn't too bad look for a 441/920/487/336 heads.
But, the 882's are mutts. Avoid these.
Unless all you want from all your hard work and $$$ is 311 hp.

91GTABird

Im wanting to do the same thing but i want to know what my CR will be on a 350 with 58cc heads. Is there a formula. If i take a 9.5:1 350 block and pistons with 64cc heads adn put my ported 58cc heads on what will the CR be?

F-BIRD'88

Compression ratio

Streetiron85

I've been wondering. Are we talking about using dished pistons here? Cause with flattops and 58cc heads the CR is awfully high.
I've been using the CR calc. below. I like it better cause there's no need to convert inches to cm. Does it show the same results for you?

http://www.kb-silvolite.com/temp/calc.php?action=comp

91GTABird

Thanks F-Bird 88'. But i just realized on my Virtual Engine Calculator the a Compression Ratio Calculator and i didnt know what the Cbr cc's meant, but i know now that it meant Chamber cc's.

I now know how to calculate any cr. What thes the cc's on my factory LB9 pistons? Its a inverted dome right, which will meen its going to be a negative number cc?

TPIgirl

I like to use this calculator

http://216.121.161.76/files/EngineCalculator.xls

I'm putting 305 heads on my 350 as well and it works out to
9.97:1 on mine.

Streetiron85

Please tell me you're using dished pistons. It's gonna blow my mind if I find out that you're getting 9.97:1 CR with flattops.

F-BIRD'88

Yes when the piston is .045" in the hole the cr will be 9.97:1 with a felpro .039" gasket.
Many common replacement pistons like FM-HP345P are .045" below the deck at TDC.

Rogue86

Can anyone tell me what the dish cc on 350 truck pistons from 1979 is? Is it 15cc?

Streetiron85

It's kinda hard to calc the cc of those factory pistons, the cc usually isn't listed anywhere either (that I know of). I've thought about actually cc'ing the cyl at tdc the way you do a head, but it would be too much trouble with the motor in the car.

TPIgirl

I'm using flattops with 4 valve reliefs, 54cc chamber, .042" headgasket, and .025" deck height.

Streetiron85

I'll assume it's working for ya... that's the bottom line

IHI

iTrader: (1)

I'm running the dreaded 305 heads with 2.02/1.60 valves. I didnt have them flow tested when I got them, but I will agree with Mike that these are going to be prone to shrouding issues, especially in my case with the 2.02's Basically one side of the valve is not flowing up to potential; if onlyI would've only took some material out of the combustion chamber. At the time it was a budget build sinceI had other things to deal with at that time. Earlier this year I bought a set of worked over Vortecs with 2.02/1.60's and they also lost flow because of shrouding-try out of the box Vortecs with 1.94's untouched flowing 239cfm@28" then the heads Vortes I got which were ported as well, flowed 199cfm@28" and now you can see how much of an effect shrouding has as well as loss of velocity. I've since sold the all new entire top end I had bought for the vortec swap and bought a set of 210 AFR's which flowed 280cfm@28" out of the box. Blah, blah
Anyways, the 305 heads are a ******* bang for the buck which this sounds like it's going to be-no offese since we've all been short on $$$ and I think for as samll as my motor was in the car-see sig-it ran pretty good for what it was. The reason compression was so low was due to the fact after the 2.02/1.60 were installed in these 305 heads they had to cut into the chamber to allow room for the valves-reason they are shrouded, and when surfaced brought my chamber size to 65cc with 4 valve relief flattops-didnt check deck heigth however, I have run 87 octane with zero ping on race day so I know it's gotta be low compression

Sitting Bull

Yeah, no one is advising 2.02 intake valves with these 305 heads. 1.60" exhausts are good but 1.94" seems to be the practical limit for the intakes, unless you know how to deshroud it successfully.

blacksheep-1

Here's a very crude but workable way to cc something. Since most of us don't own a burret, (or have broken it if we did) go scrounge up a plastic syringe, then get piece of plastic and drill a hole in it. Seal the plastic to the top of the piston (to check dish) or the cylinder, or the combustion chamber, by using white grease. Fill up the syringe with ATF squeeze out the excess, read the marks, then carefully squirt it into the hole you made in the plastic. Remember ,it has to vent in oder to fill up, then read the number again. Subtract the second number from the first and you have the cc's of that chamber (or whatever). It's not super accurate, and engine builders will laugh at you, but it will get you by.
hope it helps

92blue

iTrader: (1)

F-BIRD'88, how exactly can you bring a 58 cc head to 65 ccs? Deshrouding can get you that far? Do you just use the head gasket as a template? Do you run the risk of running into a cooling passage, or is it rather safe to try to deshroud that much?

F-BIRD'88

Yes you can get that much. Don't get carried away in any one area. use a old stock shim style head gasket to mark out the boundry. It's smaller than the replacements
composite gaskets.
larger replacement valves with a concave shaped face
add significantly to the chamber volume too compared to the flat face stock valves. My friend recently got a finished chamber
size of 64cc's with just enough chamber wall tweeking to allow the larger valves to fit the chamber . (2.02x1.60") No chamber polishing or anything.
I even questioned him on it, but its true.
I typically get 61-62cc's with 1.94x1.60" valves
and mild deshrouding and then complete chamber polishing.
Its not hard to remove that much metal.
try it.

92blue

iTrader: (1)

I definitely will. I just have a hell of a time trying to find time to finish my heads. Just got out of a fight with a computer virus, now theres something loose under my car that sounds like a pepsi cans with quarters inside. I have some legal issues to take care of with a fraudulent collection agency. Throw onto that school and work, and there is no more leisure time left. *** I can't wait til spring break already...

By the way, you've answered alot of my questions throughout several different posts. I really appreciate your help man. Thanks.

91GTABird

92Blue,
I had the same problem with the Pepsi can to. The first time it was a broken lower shock mount and my shock was rattling against my axle. The second time it was my driver side wheel bearing. Just some suggestions.

IHI

iTrader: (1)

Long story in a nut shell, car- 81 monte, was alomst uncontrolable coasting down a large hill on our way to go sking/fishing, pulled over could still hear the rocks in the can, but seen nothing under the car so we continued to the camp site where upon finding our spot I happened to have the drivers side door open while moving the car checking for nosies and seen the rear tire literally woobling in and out of the fender well, pulled off the cneter cap and 4 wheel studs were broken off and laying in there with the lugs nuts still on them. When we got the car jacked up to fix this after scamming a ride with some girls we just met, the damnn jack sunk into the soft soil and over went the jack and down came the car This took place almost 12 years ago when we were fresh outta high school, right then and there I acceppted the fact of divine intervention. Sobody was defintately looking out for us that day since we never got hurt. After we got the car fixed we had other problems that night with the local tough guys and the fact we were hanging out with their girls, so just decided it was better off to pack up and head on home before anything else could happen. More than likely you dont have broken wheel studs or center caps but that story always brings back memories.