Anyone here ever have their pistons machined?
The heads I have are the 84 CC versions that are similar in chamber shape as the 1967 closed chamber 915.
Since this thread is just over six years old, why not post an update? :eek:
I did go with the thicker head gaskets. .075 Cometics. The pistons turned out to be .012 in the hole, not the .017 that I had thought. The head chambers were at 82.5 since they had been surfaced a few times. Final C/R came in as 10.07 to 1.
It ran great with the new combination. ZERO detonation and I even bumped the timing to 18 initial and 32 total. The curve is slightly slower since I bent the tangs holding the distributor springs. Full advance comes in about 2700 rpms. I know, I know, I should have tried this before I pulled the heads. It might have made the difference. SOME people are slow learners. Count me in on that one.
I have made several changes to the car since 2013. I pulled the Lunati cam out because I wanted a smoother idle and better street manners. I used a Mopar 528 solid. It improved the vacuum numbers enough to ditch the vacuum pump for the power brakes. Still no detonation but it isn't as quick as it was with the Lunati. I pulled the Gear Vendors unit, changed from a 10" 3000 stall converter to an 11" 2750 stall from Ultimate Converter Concepts. I switched from the 3.91 gear to a 3.55. I installed a Classic Auto Air Heater and A/C setup. I had the carburetor rebuilt by a buddy who also found an electric choke kit for it. I tossed my choke years ago but with the work I've done, I want it to be a 4 season driver.
The next big thing? I want to swap to a Tremec 5 speed!
The heads I have are the 84 CC versions that are similar in chamber shape as the 1967 closed chamber 915.
Since this thread is just over six years old, why not post an update? :eek:
I did go with the thicker head gaskets. .075 Cometics. The pistons turned out to be .012 in the hole, not the .017 that I had thought. The head chambers were at 82.5 since they had been surfaced a few times. Final C/R came in as 10.07 to 1.
It ran great with the new combination. ZERO detonation and I even bumped the timing to 18 initial and 32 total. The curve is slightly slower since I bent the tangs holding the distributor springs. Full advance comes in about 2700 rpms. I know, I know, I should have tried this before I pulled the heads. It might have made the difference. SOME people are slow learners. Count me in on that one.
I have made several changes to the car since 2013. I pulled the Lunati cam out because I wanted a smoother idle and better street manners. I used a Mopar 528 solid. It improved the vacuum numbers enough to ditch the vacuum pump for the power brakes. Still no detonation but it isn't as quick as it was with the Lunati. I pulled the Gear Vendors unit, changed from a 10" 3000 stall converter to an 11" 2750 stall from Ultimate Converter Concepts. I switched from the 3.91 gear to a 3.55. I installed a Classic Auto Air Heater and A/C setup. I had the carburetor rebuilt by a buddy who also found an electric choke kit for it. I tossed my choke years ago but with the work I've done, I want it to be a 4 season driver.
The next big thing? I want to swap to a Tremec 5 speed!
