rect or oval port?
08-26-2005, 11:40 PM
#21
Instructor
Member Since: Jul 2005
Location: Oakdale Ca
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Naw, forget them '69 OP heads...you need/want/have to have rectangle port heads for your build.
Okay, I'll take the OP's off your hands....
BTW, my LS5 powered TH400 3.08 geared '57 Chevy PU, went 13.86...only work was minor valve job, minor casting flash removal, old edelbrock dul plane (so old they didn't even name it) and a Holley 750 vacuum secondary carb. Bottom end is all factory...don't recall if that was with tailgate down or tonneau cover on....been awhile
Ya....you need rectangle port open chamber heads for performance
SO how close are yo to California?
Okay, I'll take the OP's off your hands....
BTW, my LS5 powered TH400 3.08 geared '57 Chevy PU, went 13.86...only work was minor valve job, minor casting flash removal, old edelbrock dul plane (so old they didn't even name it) and a Holley 750 vacuum secondary carb. Bottom end is all factory...don't recall if that was with tailgate down or tonneau cover on....been awhile
Ya....you need rectangle port open chamber heads for performance
SO how close are yo to California?
before some-one else does 
08-27-2005, 04:21 PM
#23
Racer
Member Since: Nov 2002
Location: Concord Ca.
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The 291 head is not the same as the earlier Big Port head. They have a much bigger and better designed intake runner. Some came with 1.88 ex. valves and some take straight thread spark plugs. If you are looking for more low and midrange torque use closed chamber heads. The increase of the quench area more than makes up for the flow restriction of the chamber wall.
Last edited by chewy; 08-27-2005 at 04:24 PM.
