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301 Poly

From: Paul Hoffmeyer
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Date: December 05, 2003


j.d. The crankshaft of the '62 and newer polys is not the only difference. The bolt pattern on the back of the block for the bell housing is different, also, the distance between the two dowel pins is different by about an inch. If you could find a good '61 or earlier 318 crank and rods, that would give you about 25 or 30 more horses than your 301. There are companies making aluminum intake manifolds that with the right size four barrel carburator will give you another 30 to fifty horses. If you can get the exhaust ports polished and matched to the gaskets there's another few horses. A good set of headers and dual exhaust will let everything out, but no one that I know of makes headers for the poly that is any good. Can you weld? You could try to build your own headers. There's a place in Mpls, MN <> that will sell you header plates and tubing for you to do your own. Even with stock manifolds, you should be able to get around one horse per inch, especially if you can find a cam with a little more lift and duration. Hope this helps. Paul H


Last changed: July 19, 2018