Exhaust valve or cam reversion

hughesboysvaliant said
The compressions not that low it's not high either . With the head shaved 60 thou the bigger valves in it and a .028 head gasket we were shooting around 9 to 1 maybe a bit more. The numbers were the leak down pressure with 100 psi on the primary gauge to get the cylinder leak down %. The compression the last time I done it was in the 143 to 146 range that was with a even bigger cam than this comp xe268 I put in it back in the winter. The new comp cam intake valve shuts at 63 degrees which is 8 degrees sooner than the old cam that was building compression in the 140s so I should have higher cylinder pressure now. I think I will do a comp test today to see what I get with the comp cam. If it's a miss it's random got new plugs wires firecore distributor MSD 6a ignition box. I've wondered about the MSD box it was used but they either work or don't usually.

Trust me, if milling the heads is all you did, the compression is still low. These engines blueprint down into the high 7s from the factory. Throw the factory rating out the window. It was just that. A rating.

Chrysler had poor machining tolerances with block decks. They were notoriously tall, adding to the cylinder volume. They also routinely cast head chambers big, adding to the combustion area. All of this coupled together made for a dismally low factory static compression ratio. Generally speaking, around a .070" cut on the heads will add one full point of static compression. That means you are probably right on top of 9:1 of a hair lower.

Your cranking pressure points to it even more. If your compression was 9.5, IMO your cranking pressure would be somewhat higher. Anyway, cranking pressure is only a number. Maladies such as yours can be worked around. That cam is ground on a 110 LSA and installs at a 106 intake center line. My guess is it was never degreed. You can advance it down around 102 or even 100 intake center line and that will wake it up tremendously with no ill effects. Then re curve your distributor so you have around 20 degrees initial timing and about 34-36 degrees total all in around 2500 RPM and that thing will be a beast for what it is.