This is my first post folks, so bear with me. Finally got the 51 1/2 ton built with a 235 that numbers say is a 58-62 engine. Engine was completely rebuilt with a Patricks kit with the "264" 3/4 cam. I'm running Fenton dual exhaust with a professionally rebuilt Rochester cababulator. Ignition is a Langdon HEI. The engine had about 500 miles on it when a lifter sounded pretty loose. Cylinder 5 tappet was at .009 and tightened back up. A couple weeks went by and it's making noise again. Yesterday I tried to dial in the timing with a light and vacuum gauge on manifold vacuum. Needle is fluttering between 13-16. Thanks for any and all input.