Doom86

I have all of these great parts i collected almost 5 years ago for building a 350 that i have. Everything has been put on a seemingly perpetual hold due to bills and family being more important then the machining cost. From what i see it needs bored and a new crank (or turned both cost about the same around here). The ancient looking machinist who honed the block said "if the rings seal it will be OK with no boring".. but theres a creator you can feel in one of the cylinder walls from rust and the bearings wear nearly solid brass..

This may sound insane but I'm seriously considering building this 305 i have sitting around. It came from a 82' LG4 Z28 that was garaged ~15 years (seen 7 of them my self) ago due to body damage. I haven't checked the mileage on the original car but i was told it was 70k. When i popped the valve covers off the heads were spotless, no build up anywhere to be found and the oil laying in them was surprisingly clean.

I'm handy with a die grinder and have a full SA porting kit with other carbide burs i've collected for the job. After completely doing 2x sets of SBC heads you feel like a pro at porting. The heads are 416 casting and I've already done a set so these will be easy.

heres some of the parts i have already have;

305ci short-block (8:6cr)
416 cast heads
1.94in 1.5ex stainless undercut valves
comp xe268 cam
comp springs, retainers, lifters
JEG's moly push-rods
double roller timing chain (cant remember brand)
Melling replacement oil pump (M55?) w/ Mr Gasket high pressure spring
complete gasket kit for 350ci SBC
I may be forgetting something..

the car already has;
E4ME Qjet with AV mods and good rod hanger selection.
Performer RPM intake
All new ignition (plugs, wires, rotor, blah)
Heated O2 sensor mod.
Heddman shorties with O2 bung
3" stainless mandrel bent single exhaust with dynomax turbo muffler.
again i may be forgetting stuff its late.

Seriously if you had all this and no money to machine the 350 block, what would you do? I figure as long as i don't have to touch the 305 bottom end I'm making a good choice.
What about the compression it seems low for all this?
Any thoughts on this build?

Stekman

Tear down the 305 block. There's no way to know what kind of shape it's in until you do a complete tear down and do a full inspection and measurement.

flaming-ford

iTrader: (7)

personally i wouldn't think twice about it. build the 305 for the time being. Are those heads milled? I see bigger valves are installed so i figured i'd ask.

anyways personally, before i wasted my time, i'd pull the oil pan and check the main and rod bearings for scarring or any major problems...... if you're looking good throw it together and be done. Make sure you use a thin head gasket to keep your compression as high as possible. Also don't cut to much out of the combustion chamber as that of course also decreases compression.

if you had a little bit of money, it might be a good idea to mill the heads just moderately ........ like .020!

Doom86

I can probably get a good look at the bottom end once i got it on the stand. To be honest though I've never popped the pans off of a 20 year old SBC and saw anything as clean as this, and I've popped quiet a few hunting for heads at the junkyard too.

Is there anything i should be looking for that doesn't require a mic set? Like ridges in the cylinder walls, brass bearings and what not?

Hopefully i can get the heads off and the short-block on the stand this weekend and get a better look at the rotating assembly. I went and picked up a valve spring compressor last night so i can get porting these heads.

The undercut valves are not installed in the heads yet FYI, they are just parts i have. I figure if the 305 doesn't work out for some reason or other I'll still have a decent set of heads for the future.

Is there any other method to increase compression other then milling heads? I only ask because to my understanding I'll need different push rods if i go that route.

thanks for any input on this.

Sonix

iTrader: (1)

you'll mill the heads .020" or something, you can't even get pushrods in increments under .050". You don't need new pushrods for that.
Check them, but I doubt you'll need to replace them.

Boy that sounds like a familiar engine combo....

new pistons is the other way to gain CR, but that's harder...

Doom86

I'm not sure if you remember or not Sonix (must have been 10k post ago for you) but we were doing our builds and porting around the same time and had very like setups. Didn't you end up going with a Lunati cam? Good to see you got yours up and going. How's it running?

Does anyone think i'm going to have to pin the rocker studs or pull and tap them for the screw in "replacement" studs i have? Or is the xe268 tame enough to not cause any problems there?

If i can i may try to just re-use the original valves and maybe back-cut them my self to save cash. Though if theres much play in the stock valve guides i'll probably suck it up, starve my children for a month or so , and afford the guides, cutting for valves with seats, and milling.

Is the low compression going to be a large hinderance of power? According to the tech data on TGO the 82 LG4 is a complete turd @ 8:6:1.

Sonix

iTrader: (1)

oh that's right!
yep, I used the lunati 60103... flattened 4 lobes on it, swapped to a compxe268h. That was fun, then I bought a daily driver, and went wild on the olds. Put in the Z-25 solid flat, and am having fun with that.

- yes, you'll need to pin them or tap for replacement studs. your call. it's for the springs, not for the cam. you'll need new springs eh?
- that's what I did with the valves... backcut some old ones out of 993 heads in a drill press, and cut the 416 heads to fit them.

low compression won't kill it too badly. it'll be a big soggy down low. but you'll be able to run 87 octane without breaking a sweat..

Doom86

I have springs for them. Not sure of the part number but they're the one's comp suggested. I also have the retainers, std locks, offset locks, and lifters. The push rods are "jeg's" brand moly push rods. I'm hoping with a decent porting and the stainless undercut valves i'll have a nice set of heads to use.

anyone know any decent machine shops in central/southern ohio?

Doom86

Well i had a great day today turning wrenches. I got the 305 tore down to the short-block and so far everything is good. The lifter valley was nice and clean and not completely blacken like my old LG4 i tore down (that thing was a mess), it still has a nice greyish tint to it and no debris of any kind. I expected to find at least some carbon buildup. I think my son had more fun then i did. He got to take one of the heads off while i watched (he's 5), and all he kept saying was "this is awesome dad".. lol.

The cylinder walls look good and i found no ridges in any of the holes, besides the ones made of carbon. The only "problem" i found was as suspected the bath-tub sized dished pistons, but sometimes you got to work with what you got.

The heads are in awesome condition. I have to say I'm a happy guy. I checked all 16 valve guides and there is absolutely no play in any of them, not the slightest wobble. The original 416 heads had a great amount of play in them, nothing like these.

Tomorrow its head porting time. I got my electric die grinder, speed control, all the carbide bits you need with a complete SA porting kit. Not to mention the best tool of all for this, a rat tail file. A rat tail file make squaring the walls, and gasket matching a simple job. Learned that valuable trick from F'Bird88.

Doom86

Well i guess I'll continue talking to my self about this build. Did i put this in the wrong forum or something?

I did some serious porting today knocking out quiet a bit of it. All of the intake's entrances are rough cut, everything that can be hit with a 3" carbide tip on both heads. Also all of the exhaust runners and valve guide bosses/bowl roofs are done on one head. I meant to get some photos of the head work but my camera isn't charged at the moment so I'll get some soon.

Now something strange about these heads i found. Did GM put bronze valve guides in from the factory? I only ask because 15 of the guides are pressed in bronze guides. My old 416 heads were not like this, they were like the lowly 1 intake guide in this set that doesn't have a fancy bronze guide. I double checked the cast guide and it has no play at all.

hopefully the weather is decent tomorrow i may actually get to start on the bowl work. What I've done thus far is make the intakes taller, while correcting casting flaws, and straightening and squaring the push-rod pinch. The common wall hasn't been touched much at this point I'm going to be removing metal where it really counts here, which is the humps back towards the bowls.

stroker_SS

I have never seen/heard of bronze guides from the factory. It's pretty likely those heads were redone.

the_am_man

iTrader: (3)

Doom86, I'm very interested to see how your build turns out since I'm also running a 8.6cr lg4 with a th200c.

I'm looking forward to updates!!

Doom86

The exhaust runners/exit are completely rough cut on both heads. I spent a lot of time increasing port bias and creating a nice pocket between the walls and the guide bosses on the bigger sides of the exhaust bowls. My main goals with the porting isn't to drastically increase port volume but port efficiency at creating swirl. I'm removing metal from all surfaces but concentrating most of efforts where it really counts.

Thanks for the response stroker_SS.

These valves and seats look to have 3 different angle cuts where as my old set of 416 was only 1 or 2 (if my memory serves its been a long time). Does GM do 3 angle valve cuts from the factory?

Also i went through and deshrouded all the valves, but only slightly since we already got poor compression.

How much compression will having the heads milled .020 give me in the end? (and what head gasket?)

The Am_Man how do you like your Th200? I read a lot of people ragging on them but i honestly like mine better then the 700r that was there before. It's much more fun to drive on the highway. The only time i'm at 1500-1750 rpm is when i'm going like 15-20mph where as my 700r was there all the time it felt like.

the_am_man

iTrader: (3)

I think the th200 has its advantages... weighs about 40lbs less than a th350, better gear spread, less rotational friction, etc...

Mine seems to work fine since its rebuild, although I havent hooked up the electric lockup plug, original owner must have scrapped it with the oem carb, so I'm turning about 2,500rpm at 55 and getting 14mpg. Seems like when I mash on it the shifts firm up quite well.

I'd love to be able to see if I could lighten up my car under 3,000lbs, work the 305 to rev, try to build the th200, and see what it could do, 12's should be within reach...

also...can be swapped very easily for 200-4r which is better than a 700r4.

I've tried searching around to see what parts interchange from the 200c to 2004r, but there really isnt any info out there.

Doom86

bump

These valves and seats look to have 3 different angle cuts where as my old set of 416 was only 1 or 2 (if my memory serves its been a long time). Does GM do 3 angle valve cuts/jobs from the factory?

How much compression will having the heads milled .020 give me in the end? (and what head gasket?)

Doom86

bump

need info to continue with this.

TGO has really changed over the last few years. If i had posted this years ago this would be a 3 page discussion of the pros and cons of what i have and are doing. Now i'm begging for answers

Has everyone moved on to 4th gens? Or even worse, Fords?

seriously though thanks for the help all!

Sonix

iTrader: (1)

Figured you had all the info you needed, so I ducked out;

- I don't think GM did 3 angle cuts from the factory. Check your valve seal with bluing and a valve "cup" tool. I doubt you have good sealing surfaces anyway probably worn) so you might as well get your machine shop to cut 3 angles on them and the valves.

- .020" milling won't gain much. You can ask your machine shop, or you can do the match. measure the bore of your heads (I honestly don't remember what it is), then do the whole pi r^2 thing, and use .020" as your length. Get it into cubic-centimeters, then subtract that from your existing 58cc heads. Remember over about .020" removed means you have to true up your intake manifold to match now - hardly worth it.
If I was in your shoes i'd only cut the heads to seal, no more. I'd deck the block to zero if that was an option.
Then port it up, and use 'em. Your CR will be low enough to use 87 octane, make sure you have a short cam to keep your low end, and you'll have fun. You're going the cheap route, so you can't have your cake and eat it too (you have to watch someone else eat your cake )

Doom86

Oh there will be plenty of cake eating around my way Sonix

I've seen very similar builds producing 300+hp. If theres any truth to the famed "lunati" build they got 343hp with a very like cam (i think it was even more tame then the xe268 if memory serves) and ported 416 heads. Not saying i'm guaranteed that or anything, but I'm sure i can get into that range. Desktop Dyno is even that optimistic. And what's Fast355's 305's producing now a days? 1000hp?

Any one have any ideas what to do for the computer? it's already giving me ***** because i don't have an EGR valve, theres no place in the performer RPM. I've always read that the LG4 computer was pretty lame as far as performance is concerned anyhow.

Thanks again for the help

Doom86

The weather was great today so i got chance to work on my tan and my heads at the same time.

At this point everything is rough cut except for the bowls.

I went through the intake runners and straightened out the common wall (removed the humps mid-way through) and squared it up a bit. While i was working the common wall i pushed the wall back increasing the port bias around the guides.

Then i raised and straightened the intake roof's a decent bit.

The last thing i worked was the floor which i basically just smoothed out and slightly, and uniformly, lowered. I didn't destroy the ramp here which is easy to do if you aren't careful.

Does anyone have any information on back-cutting valves on your own? I think i may just put these 1.84 valves back in, the seats looks fresh and it would save me some cash.

Also again i ask; Any one have any ideas what to do for the computer? it's already giving me ***** because i don't have an EGR valve, theres no place in the performer RPM. I've always read that the LG4 computer was pretty lame as far as performance is concerned anyhow.

Awesome-X

You'll have to have a custom prom burned for you computer to make it run correctly. Good luck on the build you oughta post some pics!

Doom86

Custom prom then?

Isn't there a zz4 prom or something of that nature you can use as well? Any other suggestions?

right now i get a stumble around 2000 to 3000 rpm and I'm told that's due to not having the EGR hooked up and the computer is adjusting timing as if it's there.

Still need information on back cutting my valves if anyone has it.

I cant find the battery for my camera. I'll see if i can find the damned thing before i get to work on these heads today.

Doom86

Sorry for the lack of pics you all. I know a lot have the mentallity, "pics or it didn't happen".

After this last week-ends and todays effort the heads are completely rough cut and just need the surface finished with cartridge rolls. They look great to me. Much better then the first 2 sets i done. It's so much easier going at it and knowing what needs done and not going at it and discovering what needs done. ("discovering" water passages in intake bowls doesn't help matters any)

Any info on back cutting the valves my self would be great.

Sonix

iTrader: (1)

Back cutting valves;
Check this out:
https://www.thirdgen.org/forums/tech...rformance.html

Doom86

The link you posted to the pages of Vizards book doesnt show anything but pictures of some valves.

Can i do this with the sanding drums in my die grinder with the valve in a hand drill?

What if i i touch the edge of the seat on the side that i'll be back cutting? is it a total loss?

Also what will compression be if i mill .020 off the heads and go with a .020 steel shim head gasket? Will i have to use different pushrods if i do that? I only ask because i want to use the one's i have (the JEG's rods). This is assuming the heads havent been milled yet and the block still not decked.

Thanks for the help.

Sonix

iTrader: (1)

Did you read the whole thread? I described how I did it in gruesome detail. I used a drill press, dremel, file, sandpaper, etc. Keep in mind, exhaust valves are harder than a file.... Not a total loss, you can use sandpaper to smooth it out. Use lapping compound to check the valve seal before assembly as well.

No, pushrods are the same. Remember how I mentioned they are only available in .050" increments anyway?

I already gave you my thoughts on milling the heads above...

Doom86

Yeah i read the whole thread and how you did it. I'm asking if i can do it with the resources available to me.

With a standard deck hieght, slightly unshrouded 416 chambers, milled .02 and a .02 shim what should the compression be? Anyone?

I think with these heads ported, and a XE268 cam it would be a real hindrance to performance to have such low compression.

Sonix

iTrader: (1)

oh ok.
You could do it with a hand drill, would either need a vice or a helper. Your drill has a lock on function?

Fast355

iTrader: (2)

The pistons have a 12cc dish on that engine. The heads will likely come out around 60-62cc. The .016" embossed shim for a 4.1" bore will come out around 3.5cc. All togather you are looking at about a 8.8:1 compression ratio, IF your pistons sit right at the same .025" in the hole, my stock very early 1983 305 was at.

Car Craft was able to get very good HP/TQ out of a 1982 LG4 with the full dished pistons in it despite a lower than 9:1 compression ratio. They even bolted 64cc L31 Vortec 350 heads on it and ran it with a XE262-H10 cam for 325 flywheel HP. Torque was a little shy, but that was to be expected, considering they were running a single plane intake as well.

I think it is interesting how the LG4 in a F-body had dished pistons with 58cc chambers and the Trucks/Vans got flat-tops with 53cc chambers, seems backwards to me.





I milled my 601 heads .015" (51cc), ran a .016" compressed steel shim head gasket, stock flattops (5cc dish), .025" in the hole for a final compression ratio of 10.75:1. I ran a tiny 216/216 @ .050, .454/.454, 110 LSA cam in it. The performance over the stock cam was phenomenal.

One of the biggest reasons for the CCC Q-Jet setups running so poorly in the power department was TIMING related. The stock timing maps are horrid, especially at WOT. The cars ran very limited advance at all engine speeds and the trucks ran even less timing at WOT. The trucks did get better part-throttle advance though. The CCC Q-Jets also recieved very lean primary jetting, so lean in fact, I have noticed that most cars/trucks rarely go above 14.7:1 a/f ratio on the primaries. It should be around 12.5-13:1 air/fuel. This should be corrected as it will make the initial tip-in acceleration below 3,000 rpm MUCH, MUCH, MUCH stronger.

1983 LE9/LF3 California emissions G20 Van (personally read from my vans stock CCC ECM)


1985 Monte Carlo SS L69 Federal emissions

Doom86

Thanks for the info Fast355.

Thats just what i was looking for on the ECM. I've always heard the LG4 had a very tame timing table as far as performance is concerned. I looked briefly for the L69 EPROM on ebay and didn't see anything. But i am also concerned that i don't have an EGR valve (no provisions) so it's getting a stumble from 2kish to 3kish. It's smoothed out slightly at the moment but I'm running 93oc with base 0`timing. I've heard these ECMs are not programable so how can i "delete" it from the ECM?

My Qjet has primary rods from a 350 caprice. They looked slightly different then the one's out of my car so i figured I'd give them a shot and they seemed to wake it up a bit down low; the throttle feels more responsive. I have an "I" hanger with DR rods on the secondary and have tuned the AV tensioner and filed down the AV restricter. I also filed and leveled out the top wall at the back lid bolts that had bowed out and were catching the air valve.

Using that compression with flow data of ported 416 with 1.84 intakes i found on TGO DesktopDyno predicts max 340fwhp @ 5500rpm, 343trq @ 4500rpm. It also suggest installing the cam -4' retarded would be a 10hp increase while not loosing any low end torque. Is there anyway to degree a cam with-out buy some expensive equipment?

My next side project I'm wanting to work on is porting a set of those 601's castings. I just like the way the combustion chamber is designed compared to 416's. It makes much more sense on a performance engine.

Thanks for all the help

Doom86

called the 1 auto machine shop in my area and got a price on installing the larger valves with a 3angle valve job, installing springs to spec, with .020 milling. He quoted me 300$.

I'm going to hold off on all that and just install what i got. When i start building this 350 i have collecting dust that will be something to add.

I have the spring height tool and all the hardware so no big deal there.

The back-cutting will be important now to get the best flow possible with these stock valves. The one that really concerns me is the stock exhaust valve, it's so large and restrictive looking. I'm still reading and re-reading the info on back cutting, some of the jargon is confusing. My idea was to try to make these stock valves look as much like my SS valves as possible with-out damaging the seat.

Also i wanted to add i got one of the head's intake runners completely surfaced earlier today so we're almost done with these. I'm hoping to have them done by this weekend.

Doom86

It was nice today so i got to work on working on these valves.

I started out having to rig up my electric drill so it was solid. First i hooked it up to my speed controller for my die grinder, which helps a lot because i can not only control the speed but also quickly turn it off and on with-out having to lock and re-lock the "trigger". Using hi-tech duct tape i strapped my drill down on the arm railing of my deck so the valve would be pointing at my stomach. It was nice and solid and worked good.

I grabbed 3-4 of each intake and exhaust valves i had laying around from other heads i had worked to test out things on. The first step for me here was finding what abrasives to use, and when. I tried out several different things and found the best "rough cutting" tool i have is a single-cut flame tipped 3/8th inch carbide cutter. I just locked it in a set of Vise Grips. Going to the 40grit rolls next, then 100grit paper, and working up to 1000grit.

After working the test valves i worked the 8 exhaust valves concentrating most of my efforts on putting a nice smooth radius on the "margin". There's a lot of metal to work with there. I also back cut the exhaust valves and smoothed out all the transitions. They are all just rough cut at this point.

All the test intake i did turned out great looking. It's nice to have a decent set of performance valves to use as visual reference.

Again i know this is a lot of "blah blah" and little of shinny pictures but my batteries for my camera are who knows where and it eats normal batteries in a matter of minutes.

JC63199

Let me know how many horses you're getting out of this 305 when it's all said and done and about the EGR problem... I may ship my factory 305 and small budget to your place, or may just print off the thread and do it in my garage...

the_am_man

iTrader: (3)

Where are you now in this build, I'd love to know!

ap72

sounds like you just really jacked up a good valve. Competition Products will sell you a set for around $70... Jesus Christ why do people on here get other people to do some dumbass ****.

If you're willing to do all of this to a 305 it'd be cheaper and better to just by a used running 350.

I'm betting you screwed your heads up too- which is a shame because 416's ported well and put on an otherwise stock 350 with a cam do rather well...

You just turned good parts into scrap iron though.

the_am_man

iTrader: (3)

Any news here?