several issues 78 dually

[gafiredog]

Hello all, I have this 78 dually I have been working on little at a time. when I bought it the po had rebuilt the engine 350 cu in. 4 bl. rebuilt the trans. turbo 400, rebuilt rearend dana 70, rebuilt frontend, bushings, etc. I have several problems I'm stumped about. the truck had set up for about 18 mo,- to 2 years. I put a rebuilt 600 holley on it, and it fired right up when I bought it. It sat and ran 15-20 min. I shut it off. went to restart it and it acted like a batt. had run down, barely turned over. I let it sit several hours, fired right up. got warm, cut it off, same thing happened, acted like a bad batt.( replaced batt. several times) thought bad coil? put in a new dist. with a new coil. did same thing. thinking bad starter? 2nd issue, brakes needed going through since sitting up. brakes locked up. bled them, pushed pedal, locked up again, everytime this happened, put on new rebuilt calipers, new wheel cylinders in rear. when done, brakes great. let it sit for about a month . today I went to work on it, front right caliper locking up again. dont have a clue to prob. master cylinder was replaced by po. could this be prob.? 3rd issue. from time I bought it, it has a high pitch vibration. in park, and driving. po said he put wrong flywheel on when rebuilding, ( a 400) thats the prob. there, said just replace flywheel with a early one and that will fix that. also backfires through carb. now. changed to a 600 edlebrock, still backfire, no power at all. any ideas??? I'm stumped. thanks, Art