Originally Posted by
glennsexton
Welcome Prox – hopefully you will find us to be the resource you’re looking for. The 350 in a Fiero swap is certainly a popular one and there may be several here who have firsthand knowledge and some hands on experience that you’ll find beneficial.
As to your engine build – we need more information to begin to help. Is this an automatic or a standard shift car? Is this a “V-8 Archie” kit that uses the stock transaxle in the stock location? Do you know what the transaxle ratio is? The stock Fiero transaxles and the Isuzu five speeds are pretty good, but you may be disappointed the first time you try and hook up 425+ horsepower.
Is there a reason that you’re shooting for 425-475 HP? That’s a big jump over what you have and that last 50 – 100 will be real hard to get with stock 8.5:1 cast pistons. I would encourage you to look at the entire “package” and ask yourself what you really want to see when you’re done. The 750 mechanical Holley will be a disaster under 2,000 RPM. You’ll need more compression and a reciprocating assembly good to 6,000 plus to really take advantage of the head and cam combination you’ve selected.
I would encourage you to consider trying the Performer RPM manifold and an Edelbrock with vacuum operated secondaries or a QuadraJet on the heads you’ve got (remember if you use a Q-Jet, it’s a different manifold). You’ll probably see a nice increase in response and a real nice improvement at speed - especially with the Q-Jet when the secondaries open.
If you really want that much HP, you’ll be better served if you pull the engine and start from the bottom up. Lots of people talking “street racin’ smack” will tell you they’re pulling 475 horse, but few are and to really see that kind of HP, you will need to replace just about everything except your block.
Others will chime in – again welcome and keep us informed!
Regards,
Glenn