GM 604 sealed crate motor theory....

[Bos's5.0]

I borrowed a head and intake from my old boss. These are used on the sealed 604 crate motor. Aluminum head 12367712 and aluminum single plane intake. I was struck by how small the ports were in the intake.

Anyways, the heads flowed
.5---267.6
.55--255.1
.6---257.2

With intake
.5---226
.55--228
.6---230

I imagine GM had better manifolds they coulda used. Is there ANY theory that a small port single is useful in racing. It seems to me it's the worst thing you can do. The single want RPM, and you decide to choke it, making it worse both top and bottom.

Any ideas?????

[F-BIRD'88]

The port openings at the head on that manifold may be cast a bit on the small side for a GM Fast Burn head.
Matches a as cast Iron 062-906 L-31 vortec head I guess.
I guess crate engine class rule do not allow port matching work on the intake.

[rebelyell]

The sealed crate motor theory ... is just that ... ONLY theory. There are so many different schemes for getting around and/or defeating the GM seal that the factory seal premise is downright laughable.

Just because it has factory seals doesn't mean it won't get scattered and gaged ... if it runs too good.

[1980RS]

I borrowed a head and intake from my old boss. These are used on the sealed 604 crate motor. Aluminum head 12367712 and aluminum single plane intake. I was struck by how small the ports were in the intake.

Anyways, the heads flowed
.5---267.6
.55--255.1
.6---257.2

With intake
.5---226
.55--228
.6---230

I imagine GM had better manifolds they coulda used. Is there ANY theory that a small port single is useful in racing. It seems to me it's the worst thing you can do. The single want RPM, and you decide to choke it, making it worse both top and bottom.

Any ideas?????

Mine worked Pretty good. I used my ported GM Bowtie Super Victor intake. With my mild ported 062's (stock valve sizes) my car ran in the high tens.