Did some measurin and math

383 67 casting
.030 overbore with 1.90 compression height
516 heads stock valve size...I honestly guessed at 84cc as the chamber volume
head gasket is 4.410 bore with .039 compressed thickness
I measure an average of piston in the hole .034

Do the math and this is about 8.8:1

Run the range from 78cc to 90cc and its from as low as 8.3:1 and as high as 9.3:1

Not really gonna cc the heads as I have never personally done this and would have to have the machine shop do it and the motor, tho rebuilt, has about 10K miles on it so there is some carbon and what not in the chambers.

I was gonna throw this 474 purpleshaft in it that I happen to have but now Im thinkin maybe find a cam that will cater to the lower compression...any recommendations??

Should I use a thinner headgasket? Have the heads shaved?

I did notice hardened seats in the heads so they may be milled.

I dont want a total dog gotta do burnouts for my son!!....about to sell this damn motor (good runner just not a powerhouse) and build a decent 440......