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Author Topic:   461 vs 291
Dirt Newbie

Total posts: 1
posted October 08, 2002 09:55 PM
what is the difference between these heads? 461, 291, Can they be run together?

[This message has been edited by wvbill24 (edited October 08, 2002).]

Dirt Maniac

Total posts: 122
posted October 09, 2002 01:15 AM
Valve size?
Chamber size?
Plug location?
If they're the same run em.
Some of the 461's had 2.02 valves,the 291 did not.

Dirt Full Roller

Total posts: 69
posted October 09, 2002 07:40 AM
Do 2.02 valves really help when you are running a two barrel manifold and stock log exhaust manifolds? Or are you trying to water the flowers with a fire hose.

Dirt Maniac

Total posts: 122
posted October 09, 2002 11:27 AM
I'd stick with 1.94 valves for a two barrel ,in order to keep the flow good.

Dirt Maniac

Total posts: 135
posted October 09, 2002 05:04 PM
I've never seen an instance when a PROPERLY INSTALLED larger valve did not help things out. Even when the port is flow limited by lack of port area, and peak flow numbers increase very little with the larger valve, low and mid lift numbers will invariably increase, and it is this area under the curve that you are looking for, especially in a limited engine, where you need to decrease valve overlap because of restrictions in the inlet or exhaust. The old myth of "low velocity" has been propagated by the magazines since the 60's. It is lack of PORT velocity(port too big)that will kill off low end, not valve seat curtain area. My ideal 355 2bbl engine would have a smallish intake port volume(in the range of 215cc or so), a port that is raised just as high as possible to approach the back of the valve at the smallest angle so it will flow like no tomorrow, and then the biggest valve I could stuff into the chamber. And of course, look just like a set of nasty old dubblehumps from the outside.

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