CorvetteMick

I know this isn't Z06 related, but it is LS7 related. I put an mildly built LS7 in my Trailblazer SS. The build is below. The Trailblazer weighs 5500#. My question is; Would a Holley High Ram kill the low end torque? I've had varying opinions expressed. What do you gurus say?

2008 LS7 Block
Mahle pistons, 11.1 cr
Eagle 6.125 rods
Ported LS7 Intake Manifold
2008 Forged crank
C6 Oil pan/windage tray, pick up tube, dip stick and tube (wet sump)
LS7 TB
Fuel Rails
Balancer (TBSS 25% under drive with belts) 91” belt
2009 Heads (valve guides done Houston Engine and Balancing)
Del West TI Intake valves
Stainless Steel Exhaust Valves
Skoggin Dickey wet sump balancer bolt and spacer for wet sump with LS7 crank
Skoggin Dickey high volume oil pump
Katech 110 Cam Shaft, 220 / 244 @ .050, .615 / .648 lift, 110 LSA +004 (installed straight up)
Yella Tera Rockers
Morel link bar hydraulic lifters
BOSCH Injectors (0 280 158 051) Chevrolet 12576341, flow matched 60# at 58 psi

Michael_D

Off idle - mid range performance would be reduced with the Holley intake. I'd look at the MSD intake. The Holley would be better suited for a light weight car that doesn't spend much time under 3500 rpm.

Quicker

I agree with Michael. Unless you have a cam that peaks above 6800, the trade off would not be worth it. The Holley is designed more for high rpm engines. Cool build though!!

MyLS1Hauls

You will lose a significant amount of torque with the high ram...I've seen first hand, more than one unhappy N/A TBSS owner with a high ram. Since you can't use the LSXRT intake with LS7 heads, I'd use either the LSXR or MSD. My buddy is using a hi ram on his TBSS, but it is forced induction. It BARELY fits under the hood and requires cutting the cowl.

RamAir972003

Holley after doing testing here in Dallas the intake is 5500 and up past 7k so I would get even a fast unless u plan on doing a bigger motor the msd is proven 8 to ten ported over the fast....good luck.

CorvetteMick

Thank all for the replies, I talked to Holley this morning they don't recommend it either.

Mick

Da Z06

You would require a revised cam with an ICL and duration to match that intake.

That cam will not work.

JMB

Best bet would be to use the MSD ported by Mamo!