During the last race I was in, the thermostat stuck closed for a bit and over heated. The car drank some anti freeze into the chamber, the car cooled down and thermostat changed and all is well now. I'm going to pull the head and have it shaved incase it was warped, new head gasket. My question is this, anyone recomend how much material to remove bump up compresion a hair, gain a few extra HP, and still be safe and reliable on 93 octane at 7500-8000 rpm for the duration of a 2 day rally. Thanks S.Burke

 

0.040" will give you compression ratio of around 10.5:1 with OEM head gasket

0.030" would be around 10.25:1

you won't have any clearance problems with 0.040" - we have milled head 0.080" and decked the block 0.040" and still had plenty of clearance even with stage 4 cams - going more than 0.040", it would be advisable to use adjustable cam gears - 0.040" is only a little over 1 degree on the cams