72 Jimmy w/HEI Wont Stay Timed!

[frednoah]

Originally Posted by my67c20

Had the same problem. What i found was that the piece of #%$^ chrome holdown was snug up against teh manifold and had just enough pressure to make me think it was locking down the distributor. With the engine off see if you can rotate the distributor. Went back to the stock holdown problem gone.

Had issues with the timing jumping around on my truck also. Previous owner had a cheap chrome holddown that looked tight, but I could still turn the distributor by hand.