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I'm having problems getting the timing even close to being right on my '70 C10. It has a 350 in it and I have set the points dwell to right at 29-30 but can't get the timing marks to line up. By that I mean the harmonic balancer timing mark is way off by as much as 2 inches to the left of the timing indicator plate. The distributor needs to turn clockwise more but it is to the point where I can't move it anymore. The engine will start but is very rough. If I set the dwell higher at say around 40 the engine runs smoother and the timing marks are closer to lining up but still off by about 5 or 6 degrees. Is this an indication that the distributor needs to be rebuilt/replaced. It is the original and I guess I should have changed it when I put in the remaned engine back in '02.

how has it been running for the last 11 years?

Sounds to me that you're not disconnecting the vacuum advance when you're checking the timing, or your balancer has gone bad. The outer ring might have slipped on the balancer.

It hasn't been on the road for the last 2-3 years. Like a dummy I just pretty much let it sit up. Decided to get it going again a couple of weeks ago and had a friend come over to help me out. We ended up pulling the fuel tank from behind the seat to repair a tiny pin hole on the bottom of the tank that was letting gas leak onto the floor pan and dumped about 10 gallons of gas that had gone very bad while sitting up. Got the tank cleaned out as much as possible. Pulled the carb, took it all apart and cleaned it good since it was all gunked up and changed the old spark plugs. The points were changed just before the truck was last parked but guess I should check them again anyway. When the engine was replaced back in 2002 it ran pretty good but I didn't have a dwell meter or timing light so points gap was set with a feeler guage and timing was set to best running condition so I have no idea what the actual values would have been at that time. Last year I bought a dwell/tach meter and timing light as I figured it would be worth having to use with this old truck so I could get it set up closer to spec instead of just guessing at it. As I said earlier, it is the original dizzy so just wondering if that is why I am unable to get the timing set due to heavy wear or do I have other issues that need to be looked at?

Oops, I did forget to disconnect the vacuum advance. Thanks 55 Shaker.

Well, now I can't get it to even start up at all. It cranks over just fine and is getting fuel to the carb but just will not try to fire up. Should have mentioned this earlier but didn't think about it. The other day when I set the dwell and attempted to set the timing, it would crank up fine but after it warmed up to operating temp, if I shut it off and tried to crank it again, most of the time I would have to let it sit for about 10 minutes before it would start again. I finally got tired of messing with it after not starting the last time and just left it alone until just a little while ago. Does this sound like maybe the ignition coil has gone bad?

That's the problem I had and changing the coil fixed it.

are you sure you have the timing light on the right spark plug? being off by 2 inches is like really a lot. You have had it 11 years, and you never checked the timing? Did it ever run right? You could have a different timing pointer than original (it was a rebuilt engine, right?) or like the fella said the balancer rim may have slipped around, in which case you should make sure it isn't about to fall off. There is something missing here. I have no idea how you would "guess" the timing. I would set the static timing to begin with and see where you are at that point.

Yep, using the correct plug, 1st one on the right side when facing the engine. The pointer came off the old engine and was bolted to the new block which was exactly like the old one. I bought a remanufactured long block in 2002 but had to take all sheet metal and accessories from the old engine to install on the new one before returning the old one the get the refund for the core charge. The balancer ring is fine and yes it ran great before I started letting it just sit up. I have always set timing without a timing light just by turning the dizzy and adjusting it to where the engine ran the best. Been doing it that way since back in the early 70's until I finally got a timing light not long ago. Also never even knew about setting dwell, just always set the gap with a gauge and that was it. I know all of that is shadetree mechanic at best but that's the way we did it when I was a teenager and it always got us by. LOL In 1986 I bought a little S10 pickup and sold my '72 C10 so didn't need a dwell meter or timing light since the S10 was all computer controlled with fuel injection. When I got the '70 C10 back in 2001 it wasn't driven much before I started taking it all apart to do the restore which took until 2007 when it was finished and back on the road so basically it was only driven for 4 years and was not a daily driver, mostly some local shows and Sunday drives around town. In 2011 I had 2 colon surgeries and was down for almost 8 months so the truck just sat in the yard then I had shoulder surgery early this year and was unable to drive it so it continued to sit up until just a couple of weeks ago when I finally was able to get a friend to come help see if we could get it going again. Maybe that helps explain a little history of the truck since I have owned it.