 |
|
Intake runner volume 246cc-278cc 18 deg. Valve angle 58/107 Valve spacing (same center lines as GM heads) Exhuast Valve 1.625 dia. x 5.550 length* Serdi #'s 1st cut: H1X1-A1 2nd cut: H1X2-B2 Raised Intake runners 5 deg. intake flange (with GM bolt pattern) Spread port exhaust Offset lifters required Pushrods cleared for .550 offest Intake gasket FP 1282 Exhaust gasket FP 52464 HUT 1.2A Intake runner volume 270cc Combustion chamber volume 56cc Intake Valve 2.180 dia. x 5.550 length* Serdi #'s 1st cut: H1.1N1 2nd cut: H1.1N2 Intake port opening at gasket 2.25H x 1.385W Distance from floor to deck at gasket 1.14 Intake min. cross sectional dim. 2.885 sq. in. HUT 278A Intake runner volume 278cc Combustion chamber volume 56cc Intake Valve 2.180 dia. x 5.550 length* Serdi #'s 1st cut: H1.1N1 2nd cut: H1.1N2 Intake port opening at gasket 2.35H x 1.375W Distance from floor to deck at gasket 1.23 Intake min. cross sectional dim. 3.02 sq. in. * Valve length with 2" installed spring height Generally, smaller bore sizes & lower chamber volumes will cause lower air flow numbers but not necessarily less horsepower. All programs can be reduced in volume approximately 7cc which will reduce air flow above .5 lift approximately 5 CFM. |
 Click for larger version of graph |