Thread: headers

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Sometime in the near future, I'm going to junk my 305 and install a 350 400HP engine. My question is can I use my existing headers from my 305 1 1/2 tube x 2 1/2 collector or are they to small for this engine. Would 1 5/8 x 3" be better?

I'm by no means smart on this stuff,but I try to watch listen & learn.''That's why I'm on this site'' Anyway I don't know if you have it,but we have a show down here on spike tv called horsepower tv.These guys try to get as much horse as they can out of every thing they have. The fisrt thing they always do is install larger pipes.They say the less restriction the better.They like a 2 inch exhast system and the dino test uselly shows an extra 12 horses or more.Sounds like they might be on to something.

i like to see 1 3/4 headers on a400 hp small block but the1 1/2 will work it really matters what RPM you be at most of the time. i make headers and i use 1 3/4 most of the time on small blocks

The bigger headers would be nice, but you would probably have to have it on a dyno to see the improvement over what you have. Normal street driving the 1 1/2" will do just fine.