5.9MAGNUM EXH MANIFOLDS

I wish I had kept my letters from the late 1970's - early 1980's from Mopar's Direct Connection. I had wrote to Larry Sheppard's DC group and got an answer back.
I asked if running a 1965 273 Left side log with a 1970's 360 Truck's Right side log would hurt. Their answer was "While not optimized and not the best, it will not hurt the engine. If you can not get a set of headers to fit then you must do what is best with what you can get." Thorlies Tri-Y's were not being made and TTI was not hatched yet. "Stan's Headers" in Auburn WA wanted $850 for a set of headers back in 1979ish....

We had sealed the 273 manifold with silicone and poured in strong Hydrocloric acid and let it sit for 3 days till the silicone melted. This ate away a lot of the iron inside the manifold. We then filled it with BB's and mounted it on a paint shaker for a few hours to peen the insides.

Running the modified (a Little Less) restrictive 273 left log and the less restrictive 360 truck Right log did add a lot of power. But running the Iron 4Bbl 273 intake manifold we had an issue of the paint burning off the heat cross-over and I had to block it off. The right side was flowing so much better that it was pushing exhaust over thru the heat cross-over passage.