I have a 1989 IRoc and its got the base LO3. I plan on swapping a 350 TBI or TPI in but it might be a couple of months. I know I will need a better exhaust so I was planning on getting a full exhaust for the LO3 and then just swapping it over. I was wondering what I should get that will benefit the LO3 and then work for the 350?

 

Headers, cat, cat-back for the '86-'90 TPI single cat application.

 

i know that i need headers, cat and a catback but i mean for headers what size? should i get 1 5/8 or 1 3/4. i just want some opinions for exhausts that would work well on the 305 and work good with the 350 when i swap it over.

 

Headers for '86-'90 TPI single cat application: Hooker 2055HKR, or get in touch with member Dyno Don. 1-3/4" primaries are too large for a 305, marginally large for a mild 350. 1-5/8" primaries are fine. 1-1/2" primaries are good for a mild 305, too small for anything but a built-for-low-RPM-torque 350.

Cat for '86-'90 TPI single cat application: Catco 9118, several others. Just get a direct-fit type; the universal ones may be cheaper, but by the time you get them installed, it'll cost you more.

Rest of the exhaust for '86-'90 TPI single cat application: Take your pick.

 

so do you think that 1 5/8 primaries would be good for the 305 and enough for the 350 when i put one in? i don't plan on doing a very radical 350 just something with around 300 horses.

 

That's what I did.