93 firebird 3.4/3x00 swap

[Mizzouman2]

Alright. I've done a bit of research on it and have a vague understanding of the 3x00/3.4 hybrid conversion. 3.4 block and rotating assy. minus pistons and 3500 top end, minus 3400 upper and 2.8/3.1 pushrods.

I read if you keep the stock 3.4 pistons you'll get badly high compression. but if you go to the 3400 pistons, you'll keep close to the stock compression?

Does anyone have a good clear and detailed link to this swap and what all is needed? Most I've seen have multiple different swap guides with multiple different parts. what I've gathered as the most common combo is as follows, though.

- 3500 Heads/valve covers
- 3500 Lower intake
- 3400 upper intake
- 2.8/3.1 Gen 2 Pushrods
- 3400 Pistons

If anyone can help me out with this, it'd be much appreciated. I'm 19, and want to give this thing some more pep, and I'm eager to learn mechanical stuff.

[ericjon262]

order new pushrods custom length to get the right geometry, the 3500 and 3400 valve covers should interchange without problem. be prepared to be nickled and dimed to death by any engine swap, it will happen. I forget how exactly the compression ratios change, but IIRC, iron head pistons with aluminum heads results in very high compression ratios as you stated. what are your plans for the car? is this your DD?

[Xnke]

The Gen2 3.1L pushrods I used worked out just fine-it is greatly dependant on your valve job, deck height, headgasket thickness, how much has been milled off the heads, and camshaft base circle. Mine was a custom regrind to retain the use of the 94-95 OBD1.5 computer, so the pushrods were short enough to work for me. The only way to know they'll work is to measure after you've assembled the entire engine and torqued the heads down.

[koolcamaro]

3.4/3500



I have a 3.4/3500 with the 3400 pistons running off an adjusted 3100 tune. It runs really good, but I'm still within the 500 mile engine breakin period so I haven't completely opened her up yet.

Let me know if you need help. I plan on doing a thread sometime soon detailing every single part number and modification that is needed to do the 3.4/3500 hybrid. I've just been busy with school.

One piece of advice I can give you is to buy an adjustable pushrod length checker(got mine from comp cam) and use that to measure your pushrod length on the intake and exhaust valves. It's very easy to do, but if you don't know how then let me know and I can help you out!

[Thats_Marvo]

This is really cool . I have an 1993 s10 with a 2.8 I would very much like to do this build.... Questions tho. How did you tune it? What fuel pump did you use/and did you have to change the lines. R u using the stock t5 or 700r4?


Sent from my iPhone using Tapatalk

[Guest]

If you do the 3.4 rwd block and use the 3.4 rwd pistons, compression will be around 12.5:1 range.

There is a compression ratio calc at the top of this forum to get the specs.

if you use the 3400 fwd pistons, in your rwd block, you will have the CR of what the 3400 had stock which was around 9.6:1

if you get a fwd 3400, you can use the heads on up to the TB on your 3.4 rwd block. If you get a fwd 3500 block, you can also use the heads on up to the TB too.

Id recommend custom pushrods but not necessary. you will just have to measure. if factory ones will work then that just makes it a bit cheaper. If you follow someone elses build, then just use the same pushrods they used.

[Thats_Marvo]

I thought u couldn't use an s10 throttle body on any of the fwd heads. You have to use the upper and lower plenum from a fwd engine. Also what about the dis ignition I have to convert to?... What computer will I use to tune this truck .. There's hardly any tuning for obd1, or since because I have heads from a fwd block use that and what ever sensors the 3.4 block does not have don't worry about it?


Sent from my iPhone using Tapatalk