A month ago I bought a 1984 Z28 was told it was a rebuilt 454, the block has 74 in raised letters on the side which means it was a 7.4 liter, th400 and a new Moser 9" 3.73 gears. I got the exhaust leaks fixed and replaced two ebay $25 fans with a derale 2400 cfm fan. Now the car will hold 210° at idle on factory temp guage and temp will not climb. I set the timing at 6° initial and 32° total mechanical. Vacuum advance gives it 48° total at steady no load cruising speed. It has a 750 double pumper on a torker intake. I have it idling smooth at 750rpm and 15" of vacuum. Anyone else have similiar vacuum and idle speed that can tell me what camshaft they have? I had a 468 with solid cam 288/292° and 600/615 lift in the past with 850 dp and luckily that car was a stick shift because it wouldn't idle below 1400 rpm and the idle vacuum bounced up and down, basically unreadable, I had to run a 3.5 power valve in the carb.