So were getting closer with the alohol motor build. Talked to a formidable machinist about o ringing our block and head. He said with proper head / block prep and studs cometic head gaskets would work fine. So I called cometic they said the same. Prep the block and head surface to a 50 RA or better. Cometic said they have many turbo motors in the 40-50 lb boost range with no problem. We have a 671 Hampton Blower and will start out at 10% overdrive. Later on up to 25%. Anybody here running boost with just gaskets? Thanks FEDER
Did Cometic say anything about adhesive/sealant on the gasket? And, even with studs, go easy on the torque. I have seen the lower outside corner of the block break where the bolt hole is. .
I a using Cometic head gaskets in my gas 392, 871 with 10% over driven, 116 octane, nostalgic drag car. Could not keep head gaskets from blowing, obviously, so I switched to Cometic MLS gaskets. No issue ever since the switch, as I did not want to 'O' ring the block and cut a relief groove in the head to accept the copper head gasket. If you are going to run water in the block, you may have to add block sealant in the water to prevent the heads from weeping water.... Two years later, 50 (plus) passes and no issue...
73RR I didnt ask nor did they mention about sealers. Ill be careful of the torque thanks for the tip. Ive heard of some people moving up in headbolt/stud size to 9/16. Wonder if that lower outside hole would handle that? Candy Man, Thanks for thereal world input I appreciate it. We are going to fill the block up to the bottom of the front hole for the waterpump. We are gonna run it dry. Thanks again FEDER
The difference in tensile strength between the two gr8 bolts is about 6000lbs (21K vs 27K). Not convinced that the bigger bolt is worth the effort. .
The Jalopy Journal
