Aluminum 4 BBL manifold for a 64 question.

Super glue over baking soda makes a rock hard crystal like substance. Same goes with iron filings. I mounted a Performer on 65 heads and just took a 3/8 drill to the holes, fit right in there and just start leaning the drill up toward Vertical until you match the 65 bolt angle. Allen head bolts work because there is no flats to bind on the intake when you are tightening them. you can also get a ball end allen driver in the middle bolts to give the proper torque. I used hardened washers and a dose of sealant under the allen heads to prevent oil creeping up the threads. Worked great for a few months then the 273-4 lost a rod bearing and I pitched in favor of a 318 short block, but used all the 273 specific parts on it: cam, heads, carb and even intake. The teen was much stronger than the 273-4 down low and didn't suffer on the high end either.