I wanted to keep this a secret, but I must let the cat out of the bag. I rebuilt the 239 this summer. Put in a 312 crank, 272 standard pistons with the skirts cut, and G heads. I kept the same cam and lifters in, Isky E4.

My problem is I'm only good up to about 2500 rpm's under load then it stumbles, misses, looses power. I pulled the timing cover off this weekend, and my machinist came over to check if I have the cam timed right.

I'm in the 2 degree retarded slot which if I did it right, gives me 3 degrees advance. Do I need to go back to the stock cam position or must I fatten up the jets? Does the G heads flow that much more that I'm running lean? It seems to me that when the outer 2 carbs come in that's when it stumbles.

I forgot to mention I have an edelbrock 354 3x2 intake.

Any thoughts appreciated.

  Dennis in Lititz PA