Holley Stealth Ram
The Best of Corvette for Corvette Enthusiasts
Carb with right low profile intake and drop base air cleaner also
http://forums.corvetteforum.com/c4-t...clearance.html





Though the USR guys wouldn't tell me the answer to this question -- or address the effects, they claim plenum volume is unchanged after their mods. Their claim is the removal of internal supports gives back the volume robbed with slammin the plenum a bit.
Even if they remove a small bit of volume (exaggerating about the volume going unchanged), I don't see they've removed enough really matter. In general the plenum is a supply for air to the runners. If it gets too small, you'll simply lose top-end power. More precisely, hit the power ceiling sooner. However, USR's modification looks to be such a small change, you're only talking a couple hundred rpms for the biggest/highest revving motors. And, I'm going to say that's where you wouldn't NEED an HSR anyway.
From what I've seen, the plenum on the modified HSR is still reasonably bigger than a TPI. It's also gotta be bigger than a MR/LT plenum too. I certainly can't see their (small) reduction in plenum volume affecting low-mid range TQ/HP where it dynos with an advantage over the MR/LT intakes. If you want better low-end torque in exhange for a small amount of high-end power, the USR modded HSR is still in that category!
BTW: If you're really worried about the issue, why not ask LD85 if he can/will make a custom plenum for you? (Of course as big/bigger too).
Last edited by GREGGPENN; Mar 25, 2009 at 02:38 PM.
Also I did not comment on the plenum volume because so far, my car has seen no ill effects of the smaller volume so I have no facts about that, but this summer with the new cam and a dyno run I may find out more pro or con. It makes sense that a given plenum volume can only support XXXRPM/cfm etc.











