[Will]

I agree with all that these guys have said here concerning intakes. A factory iron 4-bbl intake from '67 - '72 will be a great intake for your engine. If you can't find one of these, a regular Performer intake (not the RPM) will function just like the factory intake.

The RPM intake is a good intake for the larger engines (455s) but not the best choice for a 400 unless you have ported heads and a pretty big cam.

What you need to understand about this is that velocity through the intake tract is what helps the engine make good low-end torque. With large-runner intakes like the Performer RPM or single-plane intakes like the Holley Street Dominator or Warrior you lose that velocity and thus your low-end torque. You also need to match the intake to the type of cam being used.

I'm also curious about your camshaft. According to the Crane Cams website they offer three different factory blueprint cams, the "N", "S", and "T" grinds. These grinds are now more commonly known by the last three digits of their factory part numbers. The "N" grind (Crane blueprinted 9779066, commonly referred to as the "066 grind") is very mild and a good choice for stock rebuilds/grocery getters. The "S" grind (Crane blueprinted 9779068) could be considered a "RAIII" cam but that is not it's usual designation. This is a good cam for low-end and midrange torque but because of it's relatively short duration and low lift won't work well with large intake manifolds and carburetors. The "T" grind (Crane blueprinted 9779041) is the "Ram Air IV" cam and is a pretty big cam for a street 400. That cam would work good with an RPM or Holley Street Dominator intake, but you'd need more stall converter behind it and reasonably steep gears for optimum performance.

So, looking at the cam you're running, which is probably the 068 duplicate and which is also a relatively small cam for a 400, a stock intake or regular Performer would really be the best choice.

Good luck with your new toy! It's always fun to hear about Pontiacs overseas.

Cheers,
-Will