3rdgen Fbody with 3500 heads

[ForcedFirebird]

You think 11.5CR on 87 is possible in hot summer weather? Or are you thinking lower it with a cam with overlap?

Yep.

No, I already have the cam...





I actually might try a little boost with it as well before I pull the motor to swap to 3400 pistons.


I know two people now with low 11's for compression and are running on pump gas. One has 10psi on his Mustang (iron heads), and the other is running 4psi in a 280zx (aluminum head).

[grandsport3.4]

keep it up very interested in your progress. i just got a spare 3.4 and some free.99 parts(3100 heads and 3400 top end) so im going to start my build

[IsaacHayes]

You think 11.5CR on 87 is possible in hot summer weather? Or are you thinking lower it with a cam with overlap?

[ForcedFirebird]

If you can get a way to tune, you can use the stock pistons and 3500 heads (11.5:1SCR) and run on 87 pump gas. Ben built an engine with 12.5:1 and is still running on pump gas.

[Canyonero]

The engine is in a 4x4 and I want to be able to run 89 octane, so I'd have to change my pistons to get lower compression right?

I'm not tuning at all (yet). I think I have an OBD1.5 untunable ECU.

Since nothing was wrong with my old engine, I should have taken my time and built this one up. I thought I was taking some shortcuts, but ended up wasting time and money. I could have built a bad-ass hybrid with dollars and cents I've sprinkled into this truck over the last year and a half. It's been a learning experience for sure. Now that I finally have the bone-stock 3.4L SFI in there and running good, I realize what I should have done different from the beginning.

I'm not dissatisfied with the engine though, it's a big step up from my tired 2.8L as-is.

[ForcedFirebird]

Yeah, I haven't had the justification to rebuild any other engine either. Maybe after I grenade this 3.4L.

I should learn some other things first anyway, maybe do an OBDII conversion and tune a few more horses into my current setup.

If your current bottom end is in good shape, get some 3500 heads on there.


What are you currently using for tuning? OBD1 is tunable

[Canyonero]

Yeah, I haven't had the justification to rebuild any other engine either. Maybe after I grenade this 3.4L.

I should learn some other things first anyway, maybe do an OBDII conversion and tune a few more horses into my current setup.

[ForcedFirebird]

Nice work! I haven't rebuilt an engine yet, but I want to. I'm wondering if building a hybrid like this would be too much for me to take on. I just upgraded my Isuzu from a 2.8L TBI to 3.4L SFI, maybe I should force myself be content for a while.

It's actually the same as rebuilding any other engine, but you have to research/find the compatable parts that will work best for you.

The shortblock is a standard rebuild, actually.

[Canyonero]

Nice work! I haven't rebuilt an engine yet, but I want to. I'm wondering if building a hybrid like this would be too much for me to take on. I just upgraded my Isuzu from a 2.8L TBI to 3.4L SFI, maybe I should force myself be content for a while.

[IsaacHayes]

Looks good. I've had good success with painting aluminum the trick I've noticed on mine is to get it thick with many layers so it's tougher. I've noticed on the parts I did thin it likes to chip off easy. But I'm careful with the painted stuff now too.

[ForcedFirebird]

All silver would look good. It looks good sitting there. Even the blue valve covers would look good too. Paint the LIM silver while you're at it.

Naw, going to use a set of my polished covers, put them on today to see...




Have to hit the planum with the buffing wheel again, and clear laquer everything. The LIM migh get blasted to match the timing cover, but no paint. Everytime I paint aluminum, it chips too easily and looks like crap after taking the bolts in/out a couple of times. Myabe even laquer the timing cover and LIM, but no paint.

The GM covers I made will now probably get stripped unless someone wants to trade them for an unpainted set.


Blasted the dampener and pulley today, then painted them gloss black...



Pics of them after paint, when I'm at the shop and think about it, lol.

[IsaacHayes]

All silver would look good. It looks good sitting there. Even the blue valve covers would look good too. Paint the LIM silver while you're at it.

[ForcedFirebird]

If it's only the oil pan, why not adapt a Gen1 pan to fit the gen 3 block?

Beautiful work, since I have a plasma cutter I doubt fabbing up mounting adaptors and accessory brackets will be a problem for the 3500 swap into my cousins blazer, I should be able to slice a notch out of the crossmember and box it in to clear the aluminum oil pan. I've all but lost my interest in the V8 given the work GM has done with the 60 degree engine. I'm addicted to the sound of high reving V6 engines and turbos with matched exhaust systems.

[ForcedFirebird]

Got the timing cover clearanced today.

Here's the interference...



Here's some shots after modification...









How does it look mocked up? I think the silver block is growing on me. Probably going to use a set of our polished valve covers to match the plenum (plenum is getting re-polished before install)...








Just wish I had a cam to put behind that timing cover, lol. Didn't have time today to call Delta, but by next week the cam and lifters will be here.

I think I may have decided to raise the compression a bit. The 3.4 gakets will give 12.33:1, but I am afraid the .030" clearance isn't enough after seeing Dave's valve/piston slap (.040" is ideal). The 3x00 gaskets and 3.4 piston-to-deck clearance will give ample room, but I don't know about keeping a .050" quench. 3400 gaskets will make 11.56:1, and 3500 gaskets will be 11.5:1.