Neil
1/2 ton status
I assume you already have the heads on since I saw talk of plug holes. Get real basic and see if the piston is at what appears to be TDC by just looking in the plug hole and make sure the exhaust valve has just closed by looking in the exhaust hole. When you see all of that happen, check the marks on the timing gears and see where you are. I would disregard the timing tab on the chain cover to start with. I also know that Cloyes brand (in case that is the brand you have) timing gears come with multiple marks on their timing gears, so make sure the DOT is the one lining up with the crank gear, not the arrow or square. The harmonic balancer should defintely be 8 inches in diameter if it is for a 350. A 305 balancer is 6 3/4 inches in diameter. I once read about interchanging 305 and 350 balancers that were 6 3/4 in. x 1 3/16 inch and having the assembly balanced that way. I wouldn't do it like that though, especially for any performance. Some 305 balancers are unusually wide and hollow also, maybe look for this wide 6 3/4 incher. But for goodness sake, do you have a 8 inch or 6 3/4 incher? Measure it and let's see if the balancer is a mismatch. What is the block casting #? if the oil pan is off what # is on the Crank? Should be crank casting # right in front of front main journal on side of counterweight. I'll try to help if I can by making sure your crank and stuff are what they are supposed to be with the #s, cause 305s and 350s have different timing marks.
Neil H.. Alabama.. '78 K5 400ci 4x4 AT,AC,PW Cheyenne. '74 C10 3spd/floor 250ci 4x2
Neil H.. Alabama.. '78 K5 400ci 4x4 AT,AC,PW Cheyenne. '74 C10 3spd/floor 250ci 4x2