My Fiero currently has a GM 3.4 V6 crate engine in it. It's the typ used in the Camaro / Firebird, with iron heads like the Fiero 2.8. The engine is still pretty new (under 20K miles). But I want more power out of it. I figured swapping the top end from a SFI V6 might help with that. After all, we know the aluminum Gen-3 heads flow much better than the iron heads. Plus, they weigh less.

So... has anyone tried this? If so, could you give a run-down of how you configured everything? For example, the length of pushrods used, whether or not you swapped in the deeper-dish pistons, etc etc.

https://www.fiero.nl/forum/Forum1/HTML/081853.html

Found this thread. It seems to not be worth trying to put the SFI top end on the older iron head block. Better off to just go with the full swap at that point I think. Keeping the Fiero top end would make more sense as fierosound did, if you were trying to keep a stock look. But at that point, I'd probably skip all that and just go for the 3500 or 3900, if you wanted better flowing top end; and try to make it look like it came in the Fiero from the factory.

quote Originally posted by Blacktree: My Fiero currently has a GM 3.4 V6 crate engine in it. It's the typ used in the Camaro / Firebird, with iron heads like the Fiero 2.8. The engine is still pretty new (under 20K miles). But I want more power out of it. I figured swapping the top end from a SFI V6 might help with that. After all, we know the aluminum Gen-3 heads flow much better than the iron heads. Plus, they weigh less. So... has anyone tried this? If so, could you give a run-down of how you configured everything? For example, the length of pushrods used, whether or not you swapped in the deeper-dish pistons, etc etc.

You'd have to change to 3400 pistons to match the heads. Might as well get a complete SFI engine and swap that in and get the advantages of DIS while you're at it. Run the ECM that matches the engine or a 7730 programmed for it.

------------------
My World of Wheels Winners (Click on links below)

3.4L Supercharged 87 GT and Super Duty 4 Indy #163

I already have DIS, and a 7730 ECM. I also don't care if the engine looks like a Fiero engine or not.

I'm looking for technical information... numbers... hard data. I already know the basics.

quote Originally posted by Blacktree: I already have DIS, and a 7730 ECM. I also don't care if the engine looks like a Fiero engine or not. I'm looking for technical information... numbers... hard data. I already know the basics.

The hard data seems to be that nobody has done it, probably because it's not worth it. Since for all the trouble of doing it, it seems cheaper and easier to just swap the whole engine.

There is a fair bit of discussion about Gen III top swaps over on 60*V6.com. I'm sure I've come across a few threads there that discussed technical items such as pushrod length. Maybe search over there.

it flows ALOT Better, and you need to swap the heads to do the new intakes, so its a total top-swap, not just a intake swap, the compression ratio endsup being like 11:1 or something stupidly high, unless u use the 3.4l TDC, or custom pistons, then itll be closer to normal, there are flowsheet #'s somewhere on 60*v6, but couldnt find them, your better off doing the whole 3400 swap, it would be cheaper and easier to tune.

The whole idea here is to get the Gen-3 aluminum heads on my engine. And of course, that means I have to use the SFI intake too... and maybe the fuel rail?

I was going to ask about it at the 60-Degree V6 forums first, but figured the folks here at PFF would be more friendly and/or helpful. I guess I'll head over there now.

quote Originally posted by Blacktree: The whole idea here is to get the Gen-3 aluminum heads on my engine. And of course, that means I have to use the SFI intake too... and maybe the fuel rail? I was going to ask about it at the 60-Degree V6 forums first, but figured the folks here at PFF would be more friendly and/or helpful. I guess I'll head over there now.

yes, you will need the fuelrail to match the intake setup, everything from the heads up needs to be changed....
this includes needing custom length pushrods..
and remember 11:1 compression is very high, high octane or racegas high...

you do know the bottomends a direct replacement for the 2.8/3.4 bottom end right? only "mod" you need to do is to trim the front engine mount to clear the oil pan.. everything else bolts right up... its also alot better design for oiling in the new blocks..
things u will need to change

exhaust
coolant lines
wiring (some pigtales etc, since your already running the dis system not much needed to be changed)
need to make a dogbone bracket
need to mod/customize the timing cover.
LOTS of tuning.

also you will need to make an injector harness, the 7730 is batch fire...