Iron Heads on a 3400.. Which head gaskets to use???

[Fierofiend]

hey guys.. I'm looking to go from a 2.8 to the 3400 in my fiero. I don't want to use the newer intake/ign. setup so thats out of the question.

When I swap the iron heads onto the 2000, do I use the headgaskets for the 2.8 fiero, or the 3400 Impala this engine came out of??

Thanks!

JC

[RacerX11]

Use the head gaskets from a 3.4 Camaro. And you will need the Camaro pistons, as well.

Marty

[Fierofiend]

I'm going to keep the stock pistons because I want the low 7:1-7.6:1 (??) compression that I'll get using the iron heads.

I think the 94 3.4 camaro head gaskets are the same as my 2.8 fiero headgaskets, I'll order the 3.4 ones just to be sure though.

Also, Do you know about the pushrods? I was told I can't use the stock pushrods when converting to the iron heads because the 3400 uses dif. length rods, and the 2.8 uses shorter lifters. I was told they need to be 5.85, and I heard you can use the 3400 intake rods. Perhaps you can clear this up for me???

[RacerX11]

The 3.4 Camaro head gasket is different. The fire ring is larger to account for the larger bore. I don't have the measurements handy right now, but I measured them at one time and they were different.

I wouldn't reccomend running that low of a CR. The engine will be a dog until the boost comes up. The only reason to run that low of compression is if you plan to run lots of boost, which won'tmake the stock cast 3400 pistons happy.

I don't know about the pushrods. You will most likely need custom length ones, but I don't know how long. Unless someone else knows for sure, you should just pick up an adjustable pushrod and measure it.

Marty

[Fierofiend]

ok, thanks for that info on the headgaskets, It makes sense now that I think of it.

The pushods need to be 5.850 x 3/8"

[Guest]

3/8"?! I think 5/16" will be fine.

Isn't that the length of the stock genI pushrod?

Regardless the pushrods will need to be custom, due to the roller lifters longer length over the flat tappet.

Just from my experiance a low compression under 8:1 engine really performs poorly, even if there is forced induction planned. The higher compression can actually help to move the gases through the engine, and if it's a turbocharged engine, can actually help to spool a little quicker with the higher compression, and supercharged, well this is more directly attached and a higher compression engine will help the engine rev here too. I hope this works for you though, just speaking from my experiance.

[Fierofiend]

Raven, I think you're right, it may be a little tooo low. I don't really want to take the bottom end apart though...

For the price of this motor, I was just going to get a set of ross forged pistons for my current 2.8 and go from there. It may have been a better move, but I like the design of the 3400 and I'm still young and ignorant. My current chip was designed around the 2.8, and now I'm bumped up to the 3.4, using 3.4 injectors, and I ported my lower, middle, and upper intakes too. Its probably going to run like @$$ once its assembled until I get a few more chips reburned, but we'll see. Hopefully I'll get it to run fairly decent.

A buddy of mine has a turbo integra fully built. I think he tooo went too low on the compression. No amount of tuning gets rid of his low end sputter/no go situation. Once spooled though, its hard to catch.

You live and you learn. I just want to get it assembled the best I can (correct pushrods, gaskets, intake and lifter keeper clearances, etc.) and hope for the best. Once its runnin, I'll keep ya guys updated...


Edit.. Custom pushrods from 'pushrods.net' are about $80.

[Anonymous]

A buddy of mine has a turbo integra fully built. I think he tooo went too low on the compression. No amount of tuning gets rid of his low end sputter/no go situation. Once spooled though, its hard to catch.

Possibly too much of a turbo? Just an uneducated guess...