John_B

Hey guys, I'm looking for a little help on what intake is on my car. Obviously it's a FAST intake manifold, but it doesn't have the size printed on the top like i see they are now. Is this an old intake before they started doing that? assuming a 90 or 92. Did they ever make a 80mm manifold back in the day? Because the Throttle body is a BBK 80mm. Or assuming the manifold is 90/92 is that black plate between the throttle body and manifold just a reducer for the smaller throttle body?

I'm new to LS motors, so i'm not sure how they used to be made because this is has been on the car for a while. If it is a reducer plate, is it worth an upgrade to a matching 90 or 92mm throttle body?

feeder82

One of the first they made for ls1s was a 78 mm fast

John_B

Oh, ok thanks. That's probably what it is then, i didn't know they ever made that size. Do you know if once they moved up to the 90 or 92 they were all labeled? in other words, no size on top must mean this is definitely the 78mm? Although going by the throttle body size and now knowing they made a 78 its most likely that

Black8Banger

I wouldn't be so quick to call it a 78 just by the outside appearance. The 90 also has no markings on the top. I would just take the throttle body off and check it yourself (measure the opening). I would hate for you to buy a 90/92 if you already have a 90! Also I believe the 78 uses a stock 3 bolt throttle body while the 90/92/102 uses 4 bolt. The 92 and 102 manifolds clearly say the size on top.

Bill Curlee

My fast 90 looks exactly like that! Could be a 90.

Antz97znj

Yea its either a 78 or a 90

John_B

Ok thanks guys, and I would definitely measure it before I upgraded, although I don't really plan on upgrading either way. Not the intake at least, just the throttle body if it's a 90 intake and 80mm throttle body. Seems kinda silly if that's the case to have such a small throttle body on a bigger intake.

QCVette

I agree. I have a FAST 78 and it is a 3 bolt. The 90 uses a 4 bolt.