Older Superstock GT cars with scoops

[Bryan Broaddus]

I asked Bruce Bacheldor at the Finals in Pomona about running the 69 Corvette in GT with the L-88 hood. He said no on the hood! He didn't offer any reason and I didn't push it.

[bill dedman]

I was GOING to suggest that the rationale behind open or closed-off scoops would logically lay with the engine's original horsepower factor; if the engine was out of a car that had fresh air, then the factord HP rating would reflect that, and in a different chassis, then it would be legal with an open scoop (fresh air.) That made all kinds of sense to me. Anything else, and you're not being true to the original operational parameters that gave the engine that particular factor in the first place.

THEN, before I made a complete fool of myself by posting something that had a hint of logic to it, I decided to go and see how much factored HP difference there was in the so-called "Ram-Air" (fresh air) packages that used open scoops, and the ones that didn't (otherwise identical engines, like the early Cobra Jat Mustangs, some of which had "Ram Air".)

Guess what??? NO DIFFERENCE! At some point, NHRA has decided that a fresh air package is worth NOTHING in terms of factored horsepower... but, they stilll list the different (fresh air or no) combinations.... they just give them identical horsepower.

Admittedly, I only looked at a few examples, but it was obvious to me from what I saw, that NHRA had gone through the list and either cut the fresh air motors back to the closed-in, no scoop models' factored HP ratings, OR upped the rating on the no-scoop models to match the fresh air engines' factors.

I must not have been in class that day.... That phenomenon has come about totally without my having noticed it.

Beings that there's no difference in the ratings, why would they CARE which engines have operational fresh-air systems??? I can't imagine that they would.

So, this is one in which there IS no argument that I can see, that scoops that were on a car would have to be closed off, because as NHRA has shown us in their sacred Classification Guide, they aren't worth even ONE HORSEPOWER.... Check it out...

Admittedly, I didn't check them all, but I did look at several combinations that had both underhood air vs. fresh air, and all the ones I looked at had identical factors.

It is a mess...

Bill

[Myron Piatek]

I believe NHRA use to have an automatic 5 HP factor for fresh air combos - '70's?

[Jeff Lee]

Originally Posted by bill dedman

I was GOING to suggest that the rationale behind open or closed-off scoops would logically lay with the engine's original horsepower factor; if the engine was out of a car that had fresh air, then the factord HP rating would reflect that, and in a different chassis, then it would be legal with an open scoop (fresh air.) That made all kinds of sense to me. Anything else, and you're not being true to the original operational parameters that gave the engine that particular factor in the first place.

THEN, before I made a complete fool of myself by posting something that had a hint of logic to it, I decided to go and see how much factored HP difference there was in the so-called "Ram-Air" (fresh air) packages that used open scoops, and the ones that didn't (otherwise identical engines, like the early Cobra Jat Mustangs, some of which had "Ram Air".)

Guess what??? NO DIFFERENCE! At some point, NHRA has decided that a fresh air package is worth NOTHING in terms of factored horsepower... but, they stilll list the different (fresh air or no) combinations.... they just give them identical horsepower.

Admittedly, I only looked at a few examples, but it was obvious to me from what I saw, that NHRA had gone through the list and either cut the fresh air motors back to the closed-in, no scoop models' factored HP ratings, OR upped the rating on the no-scoop models to match the fresh air engines' factors.

I must not have been in class that day.... That phenomenon has come about totally without my having noticed it.

Beings that there's no difference in the ratings, why would they CARE which engines have operational fresh-air systems??? I can't imagine that they would.

So, this is one in which there IS no argument that I can see, that scoops that were on a car would have to be closed off, because as NHRA has shown us in their sacred Classification Guide, they aren't worth even ONE HORSEPOWER.... Check it out...

Admittedly, I didn't check them all, but I did look at several combinations that had both underhood air vs. fresh air, and all the ones I looked at had identical factors.

It is a mess...

Bill

Sorry Bill, that occured maybe 20 years ago? I'm not sure when but it was a LONG LONG time ago. It's a technicality as to when and why but I'm under the impression it was a result of 428 CJ racers changing hoods from flat (Q code) to shaker (R code) and NHRA seeing it didn't seem to affect performance one way or the other. I can only offer my own experiments on my '70 AMX. I was curious in D/S what the affects were. Sealing off the scoops (which probably aren't much more; if any, effective of something like a mopar / ford shaker), and even running with and without a K&N filter I found no ET one way or another and MAYBE as much as (point) .2 MPH. And that's on a 124-125 MPH stocker.
I'm sure a 145-150 MPH SS car like a SS Dart/Barracuda or SS/AMX would see different results but NHRA has, as Bill pointed out, set the bar across the board that it doesn't seem to matter.
I still contend the scoop is a body part not an engine part and if NHRA allows cars like Hale or Teuton (non-hemi in '68 hemi A-body SS/GT car), then it should be across the board. That would include the SS/AMX scoop and the L-88 Corvette scoop.

[herbjr]

I havent read this whole thread but in repsonse to what Jeff just said, The 68 Dart/Cuda came with that car with a HEMI and a Scoop. Why wouldnt you be able to run it in SSGT. And that scoop on the AMX is a definite advantage but its there so whats the big deal.

Herb Jr

Terry your right it sounds like Heavy Elim.

[bill dedman]

Jeff,
Thanks for the info on that. What I fail to understand is, if there are NO HP changes with a fresh air system, then why not just delete the reference to it in the Class Guide? All it does is muddy the water, and it's plenty muddy already, what with the acceptance of aluminum aftermarket cylinder heads on otherwise STOCK engines, different factors for the SAME engine in different cars, the same engine with different transmissions etc.... Jeesh...

Obfuscation and confusion abounds... in an area where explicit information is critical. Amazing....

Bill

[BBF67]

Allowing ram air bodys with any engine sets one to thinking. When GM and Chrysler merge, the LS1 Chevy engine can be put in a 69 AMX factory racecar to run GT. Also look forward to the same engine in a 68 Barracuda/Dart hemi body. When looking at Fords, a 64 Thunderbolt with a 68 302 could run GT. Don’t forget about a LS1 in a Super Duty 62 Pontiac.

Yes sir, messing with the rules may give us some SS/GT cars that would cause even die hard class fans to quit paying to see.

[Jeff Teuton]

I think an Omni with a 396 Alum Head motor would be way cool!!!! And speaking of Omni, in it's day we had a cheapie Omni that had about $200 markup. By the time the factory added the things to the invoice that the public doesn't see ( 3 additional gallons of fuel, handling, 25cents to print a Manufcturers Statement of Origin, etc), dealer cost was more than window sticker. A real deal there.

[Rory McNeil]

I can`t speak for GM & MoPar, but I`m not aware of any of the Fords having different factory HP ratings between Ram Air, cold air, Shaker, whatever you want to call it. I`ve owned several factory "Shaker" equipped Mustangs, 69 & 70 R code 428 , and 70 351 Cleveland 4 barrel, the factory ratings were 300 for the 351, and 335 for the 428`s, same as the non Shaker cars. Same with my 69 Fairlane Cobras, 335 with or without Ram Air. However, in the 70`s, until the early 80`s, NHRA added 5 additional HP for the 428 CJ ram air cars, over and above the considerable factor that they had already added to the 428`s. Basically almost everybody who was running a 428 CJ car at that time replaced their Shaker or Ram Air hoods with flat hoods, rather than carry the extra weight the scoops required. As for hood scoops in general, obviously not all are equal in design. The huge 68 Hemi Cudas and Dart scoops, as well as the boundary layer designed 440 6 pack Road Runner and T/A Challenger scoops would likely be superior to, say, an 68-69 Road Runner "Air Grabber", Buick GS, or Firebid-GTO style units. I remember towing a friends 70 Buick GS to Boise , on an open trailer years ago, in a rainstorm. When we got to the track, the rain and dust had left a nice bunch of trails on the hood, & by looking at these dust trails, it was obvious that the airflow went around the almost flush hood openings for the ram air setup, rather than into these openings. Many of these scoops and "cold air" setups were simply styling gimmicks, while others, most notably some from MoPar were actually designed to be functional.

[bill dedman]

My reference was to factored horsepower, not OEM ratings.

I thought that if the engine had a factored HP rating that depended on fresh air for that rating, then it should be allowed fresh air in a GT chassis. But, since they have removed all the separate factors for fresh air engines, it's a moot point.