[rrfd43]

I was helping my neighbor with an engine change. We put in an older (pre-70) i think 350. It had the lod points distributor and short water pump. We changed over to the HEI system and edlebrock carb. The timming tab for this motor is on the left side of the cover about 1:30 to 2:00 position. We timmed it at 10 degrees BTDC no advance line on. IT runs like crap, runs on after shut off, etc. We loked at the timming om my 350 (original HEI and Long water pump). We noted that the timming tag here is at 12:00. You have to look straight down between the water pump and timming case. Why is there the position difference and it this because of the HEI or different balancer.

We did note that if we set the timming at 12:00 on the older motor it runs good.

What are we missing??

 

[Troy70SS]

The only thing you can do to really know where you are at is find true TDC and go from there. Use a screw-in piston stop to find TDC and mark that on the balancer using the existing timing pointer. The set the timing from there. Start with about 12º initial and then check your total to see where you really are. You probably want to be around 36º total.

Troy.

 

[71350SS]

Sometime around 1977 or so,GM changed the timing tab location on the timing chain cover AND the mark on the balancer too.So if you mix either one of the old ones with a newer one,you can have some problems trying to set the timing to spec.