454 info...Gen IV vs Gen VI etc....

[Canada20]

Man! that subject line is a little cryptic!

Anyway, I'm poking around e-bay for 454 goodies and something that keeps coming up is parts for a gen IV engine and I think I've even seen a gen VI listing. What are the differences between generations of the Big Block? I think I read once that gen VI heads won't bolt onto older blocks. Is this really the case or will they work with mods?

Thanks,

Greg

[jflem3]

the gen IV motor is the 65-91 motor. the gen V is 91-96 and gen VI is from 96 -current.

the gen 5-6 motors don't have fuel pump bosses(fuel injected motors) unless it a GM performance parts block. and then some of those don't have bosses either. also. the gen 5-6 motors are roller cammed and net lash built (no adjustable rocker arms.,but can be converted with roller rockers.)

the heads are not interchangable the water passages have been altered. the aftermarket Edelbrock and GM Performance parts aluminum heads will fit all the motors gen4-5-6 and( by the way they are the same heads just different brand names on them.)

gen 5-6 motors have one piece rear main seals (good thing) but flex plates and flywheels are differentfrom gen4's
From 1988 on all the 454's were injected and had serpentine belts drive (another good thing to have)

the gen 6 vortec 454's are net rated at 290hp 410-415#ft. torque.and port fuel injected to boot.and can be easily massaged to 400+ hp with mild porting new cam and headers and free flow exhaust.