Quote:

anything above about 165/170 lbs. clyinder pressure is playing with fire on pump premium.



Not really, with a well sorted out engine 205-210 psi is not out of the question on pump gas.

I have 185-195 cranking psi (10.6:1 measured static compression)on my magnum headed 360 and I run it on 89 octane.

To the OP are you sure the timing mark on the balancer is accurate? If it's not in the right place you could have more timing than you think.

With 165/170 psi you should be able to run on 87 octane.

Dave Clement Pembroke, MA 03 PT Cruiser GT Turbo 99 Dakota SLT+ CC 4x4 68 Barracuda sport coupe http://home.comcast.net/~dgc333/