I have an 86 Pontiac Fiero SE 2M6. To the best of my knowledge everything is stock with only 62K miles. I've dropped the engine and transaxle to repair a few leaks and figured that while I had it out I'd look at the possibility of increasing engine/drive-train performance. Unlike alot of posts I want to keep the 2.8L short block and was wondering if 3.4L aluminum heads would bolt on and what modifications may be necessary? If possible what is the range in production years of this interchangability? The camshaft is an additional wanted upgrade and I wondered how radical I could get with this in conjunction with the cylinder head exchange? Thank you in advance for all the helpful input.
I would think this would be similar to putting 350 heads on a 283 short block.
Leaving the block and pistons alone, and adding the aluminum heads will result in an absurdly high compression ratio. Probably 11:1 or thereabouts. If you use those heads, you will also need to use the intake manifold that came with those heads. That will preclude the use of a distributor, so you'll have to go DIS, which will pretty much require a 7730 ECM swap. It just kind of snowballs...
Better to swap in the whole Gen II or later engine. If you care about retaining the stock look, the best you'll be able to do is an iron head 3.4 from a 93-95 Camarobird. (Some people use the FWD 3400 and swap in the Camaro pistons and heads, but it's fairly complicated, if you haven't done it, before. Doesn't seem worth the trouble, to me.)
No offense but, I had to laugh when you said 11:1 compression ratio was absurdly high. I've built several small blocks for things like Novas, Chevelles and Impalas and so long as the cam was sized correctly we could get away with a 92-95 octane rating. Ran 11's and 12's in the 1/4 mile with a naturally aspirated motor. Not rocket ships but nothing to be embarrassed about. Thanks for your input though because I don't have much experience with these smaller engines and most especially the computers. Figured it was high time I learned something new.
[This message has been edited by amsowell (edited 08-28-2017).]
Dropping Gen-3 aluminum heads onto a stock 2.8 V6 short block would yield a compression ratio of around 13:1. That would be great for E85. Or you could swap in a set of pistons from an aluminum head 2.8 to bring the compression back down.
Just keep in mind that the entire top end has to be swapped over. You can't mix and match the heads and intakes. And that raises another issue: distributer clearance. The engines with the aluminum heads don't have a distributer, so the intake isn't designed to make clearance for it. You'd either have to point the intake in the other direction, or install a crank trigger wheel and convert to DIS.
Dropping Gen-3 aluminum heads onto a stock 2.8 V6 short block would yield a compression ratio of around 13:1. ...
Thanks. I didn't remember the number, but I remembered it would have been a... challenge for most people who were used to how stock 2.8s were set up. Not knowing the experience of the person asking the question, even 11:1 may be "dicey" for some.
[This message has been edited by Raydar (edited 08-28-2017).]
Swapping the aluminum heads onto a 2.8 L44 block would be kind of like trying to swap LS heads onto a 1955-96 SB.......It could possibly be done but you start creating so many problems it's just nuts....They kind of screwed the Fiero guys when they updated the 60* V6..... They changed so much that it's basically impossible to swap much around....The intake ports on the heads are completely different.
The best possible change that doesn't require hardly any weird changes is the 3.4 F-body long block swap....The engine looks basically the same, but you gain approx' 20 hp...But as important, you gain 30 Lb/FT of torque and the whole powerband is at a lower RPM....Kind of like in the old days swapping in 4.11 rear gears for better launch ability. The only difficult thing to do is to drill holes to mount the starter on the left/front side of the engine......Rodney Dickman sells a jig for doing this.
If you want to do the ultimate 60* V6 swap, there is the largest/most powerful one....The 3900 with variable cam timing/intake...making 240 HP/Torque....AND approx' 40 lbs lighter....but it has the newer OBD II control system....and that requires either a lot of electronic/programming mods, and/or the ability to not worry too much about smog laws(I live in CA so I would have to go the reprogramming route.....)
Originally posted by cvxjet: ... The best possible change that doesn't require hardly any weird changes is the 3.4 F-body long block swap....The engine looks basically the same, but you gain approx' 20 hp...But as important, you gain 30 Lb/FT of torque and the whole powerband is at a lower RPM....Kind of like in the old days swapping in 4.11 rear gears for better launch ability. The only difficult thing to do is to drill holes to mount the starter on the left/front side of the engine......Rodney Dickman sells a jig for doing this.
If you want to do the ultimate 60* V6 swap, there is the largest/most powerful one....The 3900 with variable cam timing/intake...making 240 HP/Torque....AND approx' 40 lbs lighter....but it has the newer OBD II control system....and that requires either a lot of electronic/programming mods, and/or the ability to not worry too much about smog laws(I live in CA so I would have to go the reprogramming route.....)
I had the 3.4 Camarobird engine in one of my cars. It really felt like the engine that the Fiero should have had. Once I took it back apart and built it up, it had almost as much power as my 4.9, but ended up being hellishly expensive.
I'm considering a 3900 swap, with a Beretta Getrag. Still haven't made up my mind, though. I didn't realize it was that much lighter. Even better.
Originally posted by Raydar: I had the 3.4 Camarobird engine in one of my cars. It really felt like the engine that the Fiero should have had.
The 3400 is even better than the 3.4 V6. It has more power, and weighs less (aluminum heads). Plus, those engines are a dime a dozen in the salvage yards right now. If I were in the market for a replacement engine, I'd pass up the F-Body 3.4 and go straight for the 3400. That's coming from a guy with a 3.4 V6 in his Fiero.
There is a huge difference between the 3.4 F-body and the 3400.......The 3.4 is JUST a long-block swap, while the 3400 is full engine swap...including the computer system/wiring harness.
If I were a dreamer, I'd prefer- above all else- the 3500 engine, but with an aluminum block...Approx' 100 lbs off the butt end and 210+ Hp......I don't know if it would make a noticeable difference, but the 3500 has a very short stroke which (Usually) equates to a very revable engine....The 3500 already has good torque.....
