I'm new here and need some help. I'm getting over pressure into the cooling system under boost only. I'm thinking(hoping) that a intake gasket around a coolant jacket is compromised. No issues until boost. Idles, runs and drives no problem. No coolant in oil. No oil in coolant. Hit me with a theory!
1986 Ford F-150
Short #ad
bed 2WD
351w
Holley 177 Supercharger
8.1 Compression
Sniper 2 EFI
C6 Trans

 

Oh yeah, forgot. We used them all the time with the Ford 6.0 diesels. I guess it would determine head gasket or intake gasket fairly quick. I pulled plugs and bore scoped the cylinders 1/2 an hour ago. #6 plug is oddly different and piston looks moist. All other cylinders and plugs look perfect, dry and consistent. Was also thinking of pulling off the blower quick, pressurizing the coolant system and determine if #6 is pushing coolant into the intake at the gaskets since it could be seen in the port. It's a 302 blower manifold with adapter plates to fit a 351w so there are 2 gaskets to have an issue with. Stay tuned and thanks for the help and quick response!!