Questions regarding my 1978 Avanti

[plwindish]

The biggest problem with the block hugger headers on my 76 with the 400 motor was clearing the steering box on the driver's side. The last pipe had to be "dimpled" for enough clearance. I think my ceramic coated headers are Sanderson.

[Avanti83]

A few thoughts from my 83 which I'll assume is relatively close to your 82. In this period GM was starting to leave the emissions doldrums but were still aways from decent computer controlled performance. Your computer control system is an almost complete separate wiring harness from the rest of the car and the computer is designed to run with the dissy, carb and cam combo that the engine has.

IMHO, changing anything without a complete dissy, carb and cam change will result in little if any gains in performance and reliability. Changing to headers without other changes will give a better look but little if any performance changes. As a second thought, I believe the 82 steering box is somewhat larger than the earlier ones. I could check my 83 vs 74 but they are still bundled up for the winter. To check fit, order what you want to try from Summit or other big time supplier. If they don't fit and they haven't been installed, you can send them back. From a cost standpoint, GM put their Ram Horn manifolds on there highest performance SBC's because they flow pretty well. I went to 2 1/2" on both of mine.

If I were to do what you are suggesting (and I did), save your money and buy a crate engine. I'm not convinced that your/my 305 can be brought up to anywhere near crate level performance for a small amount of funds.

I bought my 355 off Ebay for $1200 from a builder that put it together and the customer disappeared so that covered his investment after the down payment. It will kick the cr@p out of a 305 with the same money in modifications.

I bought the 383 stroker engine in my 74 for much less than that.

I'm not necessarily here to talk about my good deals on engines but make a point about dollars vs performance. In your neck of the woods there are a few engine builder that advertise on Ebay and the internet and have some excellent deals on crate motors. If you don't thrust them or my way of finding engines, Jegs usually has free shipping on their crate engines. PackardV8 on both forums also does a great job of building engines to exactly the requirements you could want.

To end the soliloquy, I'd buy a crate motor and not try to piecemeal performance into your 305. And if you are dead serious about the best setup for the car, a newer LS with computer and trans should cost about the same as a decent crate engine but will require a decent amount of installation headaches.

JMHO, Bob

Edited March 12, 2015 by Avanti83

[popeyesteve]

I checked out the available room between the engine and the steering box and it is obvious that there is no way that rear tube would clear using the Headman headers. The passenger side, no issues.

[boogieman]

There are remanufactured better looking cast iron rams horn exhaust manifolds available. They flow nicely,

take up no more room than stock manifolds, look great, and should provide the same clearance as the stock ones.

I put block hugger headers on my '35 Plymouth sedan. Had to rebuild the steering to clear where the

cast iron manifolds cleared nicely. A lot of work and expense for a small gain. Your call.