My books go to 74 and end with a 375xxxx numbers. It is probably late 70's manifold. It doesn't have enough ports to be a mid 80's lean burn. Could very well be a truck intake.
OK, good
The engine had a truck pan on it, engine block is date coded 7-6-70. The 318 had been over bored .030 ths, different cam and new frost plugs so it has been built once. Bought it as a buildable core with the intake, but the intake was not bolted on.
So was wondering if that intake came from some other year engine during it's last build.
I was thinking they started the Dual Plane intakes in '68 And 69 on the 318s and moving forward. Don't know if they still made the stock single planes after the Dual Planes came out ?? I don't know, sure someone on here knows better.
