Hi I'm just about to start up the Pontiac but I have to drill out the heads for NPT to An male fitting. My question is, what size line should I use. I want to run two lines from the tops of the heads to the top tank on the radiator. I bought 12an but now they look a little big. I was thinking I could put in a sleeve to increase the pressure, but also how they look is important. Maybe 10an would look cooler. Plus I did a search and I couldn't really find what i was looking for. Anyone done this? Thanks, oh incidentally, 331 Hemi, stockish hydraulic cam, 8 to one around ten pounds of boost. Nothing special really but it's my first blower motor. It wouldn't let me load photos of the car for some reason, anyway thanks.
No it's just a 331 hemi with the water crossover in the manifold. I talked to bob at hot heads and he recommended drilling the early heads for pipe thread to AN fittings. I'm just unsure of the size
I use 2 -12 returns to the radiator in my race car. I felt the -10's were a little small.The car has been that way for years,and never gets over 190 unless I shut the fan off.
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