Hi, I will be installing an almost new GM Goodwrench 350 crate motor. (8.5:1 compression). Into my 1984 T/A (LG4, auto trans). I want to keep it emissions legal. (Stock Air tubes, smog pump, etc...) Will I need to make any changes to my ECM? I planned on using my stock carb.

Also should I upgrade to different exhaust manifolds? (350 manifolds as opposed to the stock 305) Headers? Any suggestions on which Y pipe I should use?

Thanks for any help, I appreciate it.

 

The computer will control things just fine with the 350.

The LG4 exhaust is horrible. From the exhaust ports in the heads to the exhaust tips at the rear bumper. Best bet is to change it all out.

Edelbrock TES is the only system I know made specifically for carb applications (get the HO system, p/n 6874 - the Smog ***** will never know).

I opted for the Hooker 2055, which technically is only legal for '86-'90 TPI single-cat systems. We'll know in November if Colorado Air Care, Inc., cares about that. The driver's side A.I.R. check valve points to the back of the car, going to be a little bit of a hassle pointing it forward (haven't bothered yet).

The L69 HO exhaust system is much better than the LG4, as are LB9 and L98, but the aftermarket stuff is better than any factory system.

Oh, the LG4 air cleaner is horrible, too.