I have a 46 Merc convertible I am building. I put a Ford 302 from a 1978 ford truck into this project with a C4. Got is started up and drove it and it overheated/boiled. I drove it again and watched the oil pressure drop to zero after a few minutes. Pulled the oil pan. The bearings were shot. Had my local garage drop a Jasper replacement into my car. Same 1978 ford 302. I bought a long block, heads were installed by Jasper. Seals are installed the correct direction. Drove it home. 5 miles. Overheated/boiled again. It has a Edelbrock 289 Perfpormer intake with rear water ports blocked. I have a Champion aluminum radiator with no leaks. Installed a 1978 Ford radiator cap on because Champion plastic one sucked. I have an aluminum overflow tank. The fan is a Summit racing pusher fan. From the front of the water pump to the back of the radiator is only a half of an inch so no room for the water pump mounted fan or a puller fan. I put a new heavy duty Duralast water pump on. Still overheats. I put upper and lower radiator hoses on with internal springs to prevent collapse. Still overheats. I have put in 2 thermostats, a 160 and a 180 with the spring end of the thermostat pointing back towards the firewall. Still overheats. The intake gaskets for the 1978 motor have slight restrictions in the front water port area. Older 1968 era intake gaskets were open squares. It has 1978 intake gaskets installed. Where do I look? I refuse to believe a motor with 15 miles on it has a bad cylinder head and it did this overheating before we replaced the motor. Engine is new. Water pump is new. Thermostat is new. Radiator is new. Fan is coming on at 160 degrees. Only thing I haven't replaced is the intake and/or gaskets. I am at my wits end. Suggestions and or guidance would be a wonderful thing.