I was looking at my /6 build here, and need some opinions.
I have a '72 Iron block, bored .040, decked .100, Sent my cam to be re-ground to a 264 dur./.480 lift.(schneider) Stock valves(for now),
cleaned up ports, Offy 2x1 intake, running with a funtional hood scoop.
Question: Do I really need headers? I know they make more power, maybe 10-15hp. But can I just port the crap out of my manifold and run that? Will it kill this motor to run it without headers?
This will be driven every-day, and was wondering if it would be worth the trouble of headers. When I get a "play" car, I won't worry about it; but now I need some street advice. I'm trying to keep my 'Rod' side away from my "need" side.
Thanks in advance...
BBBanjo

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225 Cubic Inches of Iron-Head American Muscle

225 bored .040 /.100 off block, Schneider Cam 224@.050~ .480 lift - Stock valves, blended bowls, Offenhauser intake with 500 Edelbrock carb

I had a 264° Comp Cam in a 225 with a 390 Holley on a Clifford intake with the stock exhaust manifold, 2 1/4" exhaust and Dynomax Super Turbo muffler. I had 1.78/1.45" valves and both the block and head had been milled. That thing ran great! It ran better with the higher compression from the milled head/block, big valves and stock exhaust manifold than it ever did with stock valves, lower compression and Clifford shorty headers. I would not hesitate to run your combination with a stock manifold, but you do need the 2 1/4" pipe and a good muffler.

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Joshua

That intake is not really a high perf/rpm piece, so you won't gain much from headers. You should be fine with the ported stocker and 2.25" pipe as Josh said. I had a 65 Dart with a stock manifold and very similar build to yours and it screamed pretty good. Sounds like a great setup for a street car with more zip!

Lou

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Home of Slant6-powered fun machines since 1988

I agree, you can get a good "street performance' combo and make good power with a ported, 6 into 1 factory exhaust manifold combined with a big single exhaust pipe & muff.

Just be sure to check your exhaust manifold carefully before doing any porting work to it. (cracks and warpage) Many of the used SL6 exhaust manifolds are in poor condition and not worth putting time into. Even on nice ones, I tend to do a "rip & run", quickie port job, that way I don't get up-set when the manifold cracks and needs replacement after a year or two.
DD

What about an 'extrude hone' on the exhaust manifold?

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

I started porting my manifold today, got 3 done, and the outlet. I can see the difference just by looking. Lot of extra meat in there! Carbide takes care of it, though. Just for notes: the two outer ports were much less of a uniform shape, and smaller. I gasket matched everything, and those two required a lot of cutting.
Thanks everyone!

So far as honing, like DD said, I hate to put much money in it.

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225 Cubic Inches of Iron-Head American Muscle

225 bored .040 /.100 off block, Schneider Cam 224@.050~ .480 lift - Stock valves, blended bowls, Offenhauser intake with 500 Edelbrock carb