Port/header interference? [Archive] - Chevelle Tech

: Port/header interference?


ro9397
Jun 6th, 05, 3:06 PM
GM requires LT1/LT4 type header flanges for my chosen "Fast Burn" crate motor because the exhaust port is elevated. Only Edelbrock supplies headers w/the air tubes required to pass emissions tests.

E. at Edelbrock said:
The Edelbrock headers alternate between 1-3/4" & 1-5/8" tubes (to maximize scavenging effects?) Per each cylinder bank, half the tubes will clear the ports (1-3/4"), half the tubes will slightly block the ports (1-5/8"). The LT1/LT4 requirement is inaccurate. Standard headers will perform fine as long as there is a good seal. A Fel Pro gasket kit w/some trimming will provide a good seal.

Is E. right or wrong? Why?

An LS1tech.com forum member suggested lowering the header mounting hole .2", elevating the header .2" & insuring good port clearance.

I need a reliable reply or must settle for the 30 hp less ZZ4 motor.

Thanks all.

ro9397
Jun 7th, 05, 10:36 PM
Sorry for replying to get noticed by a knowledgable member.