Thread: intake manifold #458520 info.

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Howdy, anyone know much/anything about the GM 458520 intake manifold (alum./spreadbore)?

just wondering if it is suitable for mild street/strip use, or should i go with an aftermarket (thinking either Performer RPM air gap, or good ole 300/36 Z28 type).
...dont want to spend the extra $ if im not going to get a performance gain etc....

Specs on engine if it helps-
10-1+/- final compression
Comp Cams 280 magnum
heads have performance work etc... 2.02 intake valves etc...
Currently wearing the above mentioned 458520 intake with Rochester carb... and runs strong/smooth etc...

is the the stock intake for an LG4?

you'll get the best low end torque from a gm manifold but they peter out after that...

firebird, im not exactly sure what the manifold was from originally. It is currently in an otherwise substantially "correct" 65 Chevelle SS.

Was wondering if anyone was familiar or better yet running one of these manifolds. , just trying to get some feed back.

Im thinking strongly about buying a factory GM or Holley (300/36) Z-28 type, but who knows!

I'm using a stock aluminum intake on a 79 350 for now. I'm switching to a holley 300-38 whenever the weather quits deciding to suck. Seems like mine has some pretty good low end torque. Can't say much for the top end now, mine sucks. Seemed to do good when it ran right. Does it have an EGR ?