I'm looking at ways to help out my flathead 6. It's not your typical flathead usually talked about here. It's in my 41 Pontiac-239 cid. I havn't found any performance parts or really heard what to do with it. I would really like to keep the original drivetrain. It's not going to be another sbc car. I was considering milling the head and replacing the 1 barrel with a Rochester 2bbl or a pair of Holley 94's on a Y adapter. And opening up the exhaust flow with a bigger pipe. Maybe even doing some porting on the head. Any help especially with the head porting is needed. Am I on the right track here? Any other thoughts? The car also came stock with a 4:30 gear , and manual 3 speed trans.
head milling more carbs better exhaust all great ideas if you want to go even further i have an N.O.S. never installed isky performance cam for your motor specs 320 lift 264 duration intake 24-60 exhaust 64-20 this should really wake up your motor and give it a cool sound as well $ 165 + 14 lbs shipping from 93535 john pm me if interested
All the usual tips for flattie V8s pretty much apply to your 6, with the exception of relieving the block. Not needed because the valves are'nt shrouded on the six. Chamber reshaping is questionable on a street flattie, you can do more harm than good. That cam offer sounds good, plus head mill and split exhaust manifold, or better, a set of headers. Forget the Y, not too hard to fab up a new twin carb manifold.
Whats a good amount to take off the head? There was an optional high compression head , but i'm not sure how much would be needed to get to that point from my standard head.
Thanks for the offer on the cam, do you know anything about valve to head clearance with that cam, especially when I mill the head down? I'll save your info and get back to you when i'm ready. I have to pull the head off and check some other stuff over first.
they used to be raced, I dont know why? they must have been good runners. for awhile they used them at the lakes and circle tracks. I recall riding in my buddy,s mom,s 39 pontiac 6 sedan, and it scooted good, we always would have her speed up over 'thrill hill' on the way into town in Yucaipa ca. back in the 40,s.
Given the rarity and the good price, you'd best grab that cam while the offer still stands. You can always thrash out clearance problems later. Assuming you have the head off now, measure the stock valve lift then "clay" the head over the valve and determined how much clearance you have with the stock cam. 3rd grade math will then tell you how much you'll have with the hot cam. Mill the head so that you'll have .050" over the valve. As someone else has suggested, fab your own 2 x 2 intake from square and round tubing. Either split the manifold or build a set of headers.
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