do these have egr passages in them, or do the f-bodies get the egr gas from the exhaust manifold like the vette.

and do they have the correct bolt pattern for a 89 LO-3 intake ?

what CC's are they ?

how much better are they than my stock heads ?

I like the log manifolds don't ask why, which ones were the best 305 h.o. ... tpi 350 ... and is there a difference in the two, i know the LO-3 probably suck.

best factory Y pipe, I could probably get away smog wise if the 89 came equipped stock with the dual cat exhaust, if not which were the best flowing

btw only the topend is LO-3 parts the bottom end is a 1990 L-98 corvette 350.

thanks

 

The L98 083 casting heads are much better than LO3 heads, especially on a 350. They are cast iron rather than the '86-1/2-up Vettes which were aluminum. They have the exhaust cross-over port so your LO3 EGR will work without an external line.

The chambers are 64cc, if that's the "CC" question you had.

305 and 350 TPI exhaust manifolds are the same, and much better than LO3.

Dual cats were a G92 option in '89. But not on TBI. You could probably get by with them, but otherwise the TPI single-cat y-pipe was the better part. Along with the rest of the TPI exhaust cat and on back.