Considering a head swap, suggestions?

I haven't seen any dyno numbers from boostedrs on here or TGO, if there point me a link. Tiago (that was who I was trying to think of), has proven dynos numbers a few times over, along with a vid, that I lost from when my laptop crashed.

[Superdave]

like .080 over or so.. lol

the 3500's bore is .2 larger than the 3.1.. the 3500's combustion chambers barrely fit the 3400.

[ForcedFirebird]

There's a 3.4 in a 4th gen F-body, I can re,member the guys name, but he had highley ported heads, intake, large cam, custom pistons, etc at something like 18 PSIG, made just under 400 HP and over 400 ft/lbs of torque

Boostedrs has gotten over 400RWHP on a 3.1 in a 3rd gen Camaro and he got deep into the 12's with a stock converter and 9" slicks with a 4:11 rear end.

Currently I'm running a stock replacment hypereutectic piston in my boosted hybrid and the pistons looked just fine when I removed the heads after two years and MANY miles of abuse, so you don't need to spend a LOT on pistons to make a combination work.

I agree with good tuning I have seen 30PSIG in a Reliant K-car with stock pistons (should have seen what happened to them after installing a more efficient intercooler, crumpled tinfoil,lol). I got these Keith Black custom turned pistons for $120 (same price as the hypers). As far as the manifolds, the stock upper on the gen1 is the restrictive part that is going away on the current motor anyways.
After more research there are people running higher SCR and lower boost, so the new motor might still get some AL heads. If I have to I can run a mix of race and high test. This car is not my daily driver, it's a project that I can take out for a drive and to the track(I've got four other vehicles). I almost grabbed a V8 for it right after I got it, and decided to see what I can get out of the 6er (so far already spent 1/2 the price of the V8 haha).
How much comp should I expect with the 3400 heads and RWD pistons (or just the size of the chambers and I'll figure it out)?

But remember, he can't use the 3500 top end. the combustion chambers are too wide for the 3.1 bore.

Even .030 over?

No, the 3400 heads require the 3400 LIM, at least. Or a completly custom intake manifold.

You'll only be limiting yourself, the most I've seen out of a iron head was well, there's two, TWO that are exceptopns to teh rule and they are both turbocharged, high;ly built turbo examples.

There's a 3.4 in a 4th gen F-body, I can re,member the guys name, but he had highley ported heads, intake, large cam, custom pistons, etc at something like 18 PSIG, made just under 400 HP and over 400 ft/lbs of torque, the other is Curtis Walker's Z42 (no longer in teh car), that made almost as much at a slightly lower PSIG of around 8 to 10 PSIG IIRC, but had even more into the build,parts and time, than the F-body, was capable of runing much higher boost pressures, but thechassis just could not handle it.

Now compare that to stock or nearly stock 3400s running somewhere between 10 and 12 PSIG and making 350+ HP.

Even if your goals are not that high, the more eficiant breathing and better combustion chambers will yeild a much nicer driving and much more effciant engine overall using the genIII top end on your genI bottom end, with the change in pistons. Currently I'm running a stock replacment hypereutectic piston in my boosted hybrid and the pistons looked just fine when I removed the heads after two years and MANY miles of abuse, so you don't need to spend a LOT on pistons to make a combination work.

My nubers were lower than they should have been on the dyno, due to a lean AFR and intake tubing tahtw was too small, along with a turbo that was on the small side, but my torque numbers were good,

Take this oprotunity to build something that you'll enjoy and be able to use day in day out, with a little bit of "ooooo" factor when you popo your hood, even in N/A form.

Just imagine taking a 3400 top end and porting it. Starting with something that usually outflows a ported iron head and making it flow even better.

[Superdave]

nope, the iron head stuff and aluminium head stuff are totally different.

that plenum may work on a FWD 3.1 LIM but the ports are still small.. and i'm pretty sure that the 3.1 LIM won't port match to the 3400 heads.

[ForcedFirebird]

Guys on the f-body site have gone .030" over but say that's it, that's as far as anybody dared. I can work the iron heads and keep the stock MIM and LIM. As far as the plenum, I'm getting one of boostedrs' UIM/plenum because I am getting the flanges CNC for him and getting a good deal.
Will the 3400 heads work with the LIM from my 3.1?
http://60degreev6.com/showthread.php?t=35562

[Superdave]

By how much? I'm getting ready for a .030 over 3.1 build with forged internals (just picked up some Keith Black pistons). Guess I might just work over the iron heads.

more than you could safely bore a 3.1.

use 3400 heads and lower intake manifold with a 3500 plenum, port match everything and you'll be in damn good shape.

The 3.4 iron heads are EXACTLY the same as the 3.1 iron heads, whihch are EXACTLY the same as the 2.8 HO Iron heads, so the 3.4 Iron heads flow a LOT less than any aluminum head.

I would forget getting the deal on teh iron head pistons and build something that will have more power using the available aluminium heads.

You'll get it all together with the "deal pistons", spending MORE money on the heads trying to get them to flow, as good as a stock 3400 head, and end up with less power and more p[rone to detonation, than using the aluminium head as well. Aluminium heads are less prone to pre-det, due to the fact that the aluminium pulls more heat away from the cylinders faster than iron heads do. The accepted running compression ratio is accepted to be a full point lower using aluminium heads, effectivly, than using iron heads with the same SCR, due to the heat loss, hence why most companies can run higher SCRs with less problems with pre-det, along with other variables like chamber and piston shape, but the material has a huge effect.
Speaking of chamber shape, the aluminium head has a MUCH superior heart shaped design that promotes swirl and fuel suspension to get a better overall burn over the iron head.

So in short those "deal pistons" that you are about to buy, will not be so much of a deal, when you are limiting yourself.

[ForcedFirebird]

But remember, he can't use the 3500 top end. the combustion chambers are too wide for the 3.1 bore.

By how much? I'm getting ready for a .030 over 3.1 build with forged internals (just picked up some Keith Black pistons). Guess I might just work over the iron heads.

[Superdave]

if you swap heads, you will need to swap upper and lower intakes aswell.

your best bet would be to go with a 3500 top end. the 3500 heads have a 32cc combustion chamber. on my motor (currently 9.2:1 with ironheads forged pistons and .060" gaskets) i figured around 11.35:1, wich is still streetable with good fuel, but with boost its to high. another thing ot keep in mind is the headers are gonna need to be custom built aswell.

now you run into the issue of the distributor. it may clear the upper intake, but i cant confirm that. if you want to swap to dis, you will need a crank trigger, as your block doesnt have the provisons. the 60 degree store has one listed that will work with any gm dis. as for computer, i think with your current setup you would be better off to go with a stand alone such as a megasquirt and get rid of the rising rate regulator.

But remember, he can't use the 3500 top end. the combustion chambers are too wide for the 3.1 bore.

[ForcedFirebird]

MS is comming, all in good time. No the dizzy won't clear the manifold but there is a way around this by simply making the dizzy longer. this will cause clearance problems with my stock hood - that I want to keep.

[sharkey]

if you swap heads, you will need to swap upper and lower intakes aswell.

your best bet would be to go with a 3500 top end. the 3500 heads have a 32cc combustion chamber. on my motor (currently 9.2:1 with ironheads forged pistons and .060" gaskets) i figured around 11.35:1, wich is still streetable with good fuel, but with boost its to high. another thing ot keep in mind is the headers are gonna need to be custom built aswell.

now you run into the issue of the distributor. it may clear the upper intake, but i cant confirm that. if you want to swap to dis, you will need a crank trigger, as your block doesnt have the provisons. the 60 degree store has one listed that will work with any gm dis. as for computer, i think with your current setup you would be better off to go with a stand alone such as a megasquirt and get rid of the rising rate regulator.

[ForcedFirebird]

I haven't flowed an iron head to compare its flow vs a gen 2 3.1. I have the 2.8/3.1 heads flowed and on the site. I wouldn't use the 3.1 heads when you can use 3400 heads. 3500 heads won't fit a 3100 bore.

The iron heads have a lot bigger CC than the aluminum heads. I can modify a 3400 head to have a large combustion chamber but you would still be running high compression. With proper tuning and a good cam, thats not a problem.

SFI requires the ECM, not the top end. The SFI manifolds flow better than the MPFI manifolds. Again, not sure on iron head stuff, so im commenting on aluminum head.

How much could you reduce the SCR, and how much would you charge? Also would be interested in some higher lift springs as the 1.7RR's broke one of my stockers.
EDIT: Are the 3400 heads compatable with my IM?

[ForcedFirebird]

Watch ebay for cylinder heads. I never pay more than 50 plus shipping for a set, unless i have to have them asap.

Thanx for the tip, seems like there are a lot of bent valves on there!!! Do you think many people re-install the pushrods wrong, lol?!

[Superdave]

your best bet is to have the pistons modified (if you're worried about the compression). Use a complete 3400 top end, switch that 3.1 over to DIS and run it on a Jbody/Lbody ECM and harness. you'll pick up a ton of power.