Inliners International Forums General Discussion Engines Chevy van inliner

Hi
I recently found this site. Very nice to see people talkin´about inline six engines and vechiles. I live in Finland, Europe.
I have 1974 chevy van G20 with 250cid inline six.
This is old emergency car 40 000 miles behind, not very much.
I will make some engine engine uppgrades, new intake manifold, carburetor, headers and distributor. Distributor is allready coming, Performance Distributors Street/strip distributor. I had original point-cat distributor and I didn`t like it. In chevy vans firewalls are quite near engine, and there is not much place on the top of the engine. So I ask, do you know, if there is enought place for Offenhauser or Clifford intake manifold. Are those much bigger than original manifold?

fron what i remembered when i pulled my old manifold off, the Offenhauser was pretty much the same size. In fact i know it was because the hea riser part of the intake bolted up perfect with the het riser from my old 250 manifold. Not sure about Clifford but Cliffords does not fit with stck manifold so...

I have seen inthe later yrs 60s a van with the offey and was a 3x1 intake. But as for the clifford yes it is a little bigger But it should still fit. But for as big & heavy the van is I think I'd stay with the offey intake. Mainly because it has better low end power & tork. The clifford will work But it is & was designed for mid range & upper end power. And I'm not sure what you have in mind for other engine mods. cam,head work, carb. Hope this helps.}[oooooo]

Thanks for your replies...
I have thought to go with offy manifold. I will change intakemanifold and carburetor first. I got some advice that Holley 390 cfm or Edelbrock 500 cfm could be good choices...

hey Twisted, that was just what i was looking for (Offy has more torq) Now i know which one to go with !!!!

Well that's not quite what Larry said. He said the Offenhauser will give you more low end torque. The Clifford will probably give you more peak torque if you raise the compression ratio enough and run a "lumpy" enough cam. But the peak torque will be higher in the RPM range with the larger runner Clifford than the smaller runner Offy.

I concur completely with Twisted and will recommend the Offy for a mildly built 6 with or without extra headwork. For more radical builds the Clifford will get more air into the engine at higher rpms increasing overall power.

-magic mike-

chevyvan your welcome .Magic mike thank you for the back up. You can also go with a vac.sec. holley 450 But THEY ARE Priceeeeeeeee. Hope this helps.}[oooooo]