Quote: Are they "logs" as in lo-perf or the HP manifolds.
If truly the logs, I would try a set of headers with the thicker 3/8" flanges. Or not waste my time. Too much left on the table.
Did you see the dyno testing done on the 440 mentioned in this thread? I went through the 6 pages and read everything.
Going from logs to HP manifolds was of little beneficent at the hp level they were at (stock intake, cam and carb I think) and it looked like over 3500 RPM the manifolds were a choke point.
Headers all the way.
I have manifolds on my Duster that are going in the bin, the fact I'm leaving at least 40 hp on the table irks me badly.
