i have a 54 chevy with a 235. it has headers and holley 390. i just put a new distributor in it and am having some problems. at mid to high rpms it backfires and pops very badly. it seems to run ok until deceleration when it pops and backfires. there are no timing marks on the flywheel housing to time it exact. any ideas if this would be timing or maybe something else. any ideas would be great! thanks in advance
There are indeed timing mark on the flywheel , you prolly have the firing order out one or three cylinders ~ it goes 1 , 5 , 3 , 6 , 2 , 4 . You can use a vacuum gauge @ idle , set the timing for the highest _steady_ vacuum and it'll be dead nuts .
Discerning The Firing Order By removing the valve cover and watching both the first rocker and the flywheel mark (triangle or BB) as you rotate the engine in it's running direction ~ as the flywheel mark lines up with the needle pointer in the window over the starter motor , the valve will be seen to close ~ this indicates # 1 cylinder is in firing position , now set the # 1 spark plug wire in the dist. cap hole that's aligned with the tip of the rotor and then insert the rest of the wires in the proscribed firing order.... If the flywheel mark aligns with the pointer but the valve isn't closing , you're 360° out of time ~ rotate the crankshaft one full 360° revolution and you'll see the valve close as the miark lines up . Not : you DO NOT need to move the distributor ! . just line up the plug wires in the correct order , beginning of course with # 1 . There's also an older post in here about proper distributoe installation but don't take it out as it's tricky to get the oil pump lined up again . I hope this helps .
