3500/3400 Hybrid (not the usual kind)

[RacerX11]

OK..I have been away for a while, and havent spent as much time tinkering with the V6's. I just picked up a new toy ('88 Fiero Formula 5-spd), and am getting back in the game.

I have a pile of parts I would like to put together to make a decent motor for the Fiero. I have a low-mile 3500 short-block, set of '03 3400 heads, 3500 upper intake, 65mm TB, Fidanza aluminum flywheel, and a stock 3400 cam.

I have searched, and found tons of info on using 3500 heads on 3400 bottom ends, but don't see anybody running the 3400 heads on a 3500 bottom end. I know the 3500 heads are better out of the box, but I would plan to do a decent port job on the 3400 heads, and open the combustion chambers slightly. I would prefer to use 3500 heads, but wanted to work with the parts I already have on hand. The 3400 heads should result in a decent compression ratio for a NA build (I think I calculated around 11.4:1 with stock combustion chambers). I would use a reground stock cam and a set of headers.

Any thoughts on this plan?

Marty

[ForcedFirebird]

Go for it! I actually thought about doing the same since I also have the same mix-match of parts from using the good stuff on each motor lol.

Don't forget you will need to use and external DIS trigger, or press a new ring on the crank.

[RacerX11]

I planned to use the external DIS crank trigger setup.

[SappySE107]

Compression isn't worth the velocity and flow lost IMO, but either way it isn't an iron head 2.8 motor:P

Welcome back

[AaronGTR]

Couldn't he make up for some of that with a decent porting job?


But anyway, I wouldn't used a reground stock cam. Press on lobes=yuck! Ben can get new cams from Comp now ground any profile you want and they won't chew up the oil pump drive gear like the billet cams so why not use one of those? Figured since you've been gone a while you might not have known about these yet.

[RacerX11]

Thanks...I guess I am not up to speed on the current state of the 60degV6 cam market. That is good there are more options available.