what size headers should i use on a 305 tpi engine. 1 5/8 or 1 3/4? does the brand of the headers matter that much. i'm going to look for a used set. and what size exhaust should i run. i'm thinking a 3 inch flowmaster exhaust. my car has a 2 3/4 stock exhaust on it now in great shape. should i just replace the muffler and gut the cat. i am doing cam and heads on the car. thanks for any comments.

 

Stick with the 1 5/8" primaries fro better low end on the 305. You can use a full 3" like I have even with a high flow cat. As you have stated in other posts, you live in California so you might want to keep it emmisions legal. It will sure save you lots of headaches latter.

Ozzy

 

what a bought brand , does it really matter. i'm going to buy used ones so whatever comes up i'll buy for the best price. i live in ohio and we just gut are cats.. thanks for your input.

 

Sorry for the mixup on the state, thought I read another thread were you stated you were from California.
If you can get your hands on a set of stainless headers it would be better. Specially if you plan on diving it in the winter. Tubular steel I've heard don't last as long with de-icing salt on the roads.

 

My 305 liked the Dynomax shorty headers i put on it. I think the headers and catback were worth about 17 rear-wheel horsepower if memory serves me correct. They have 1 5/8-inch primaries. I think the Edelbrocks either have 1.5-inch or they are stepped to 1 5/8, but not sure. These seem to be rather common and might work as well. As a reference, i've seen many 5-liter Mustangs pick up with 1.5-inch primary tube headers, but i think that size may be a rarity within the Chevy third-gen aftermarket. I wouldn't go with the 1.75-inch headers unless you are planning on adding more cubic inches to the engine and bigger cylinder heads.

 

edelbrocks are 1 5/8 as i understand and will work well with a 305, they fit great and added nice power, i have a 3 inch flowmaster exhaust, although its added nice power and sound, i wouldnt say there arent better ones out there although im very satisfied...and a high flow cat will work nicely and be nice and emissions legal