GMMG ZL1 - Page 5

sYc · #41 01-12-2003, 06:57 PM

Actually the first Grand Sport ran a regular production "race prepared" small block. It resides in a garage outside of Pittsburg, after passing through Yenko Chevrolet. It is quite impressive to see, as it is complete, with paperwork. It has been offered to the sYc, but not for sure what best to do with it. Certainly a valuable piece of history.

**Stefano** · #42 01-12-2003, 07:03 PM

Tom,
Please explain. Was it raced by Don Yenko or race prepped by Yenko Chevrolet and what year(s)?

Keith Tedford · #43 01-12-2003, 07:06 PM

Regarding warranty on the '69 COPO cars, we had no problems at all. Right from the begining I had ring sealing issues and the engine got re-ringed under warranty. A transmission problem was corrected as well. No one could make the shifter work properly. One of my friends had no end of problems and all were looked after under warranty. The 5/50 warranty was good insurance. None of the other companies gave much more than 90 days warranty on their top cars.

sYc · #44 01-12-2003, 07:21 PM

Following GM's ban on racing, about 1964, the Grandsports were sold to the public. One of them was bought by Grady Davis (Gulf Oil). This is the car that Don Yenko and other Pittsburg area racers raced. Gulf Oil picked up where Chevrolet left off. They had their own R&D department, strictly for racing. They would run a 327 (on one of their many dynos) until it broke, just to find the weakest link.

As per the engine, is was removed early on, once the aluminum small block was ready. If memory serves me correct, it features some type of injection, such as a Hilborn unit. It has been several years since I have seen the engine and all of the documents that go with it, but I have no doubt it is legit, as well as all of the other Corvette racing artifacts that reside along side it, including the first trophy ever won by a Corvette (racing).

Seattle Sam · #45 01-12-2003, 09:02 PM

I have seen the Gran Sport that Supercars referred to, here in the Northwest. The original engine for it sits on a stand, and is quite a piece! It's a small block Chevy, with provision for a road tube at the top rear of the motor (all small blocks through 1967 I believe). But it's an alloy block, not iron! The Winters Foundry mark on the aluminum intake made for those four twin-throat Webers is also awesome..

I don't have a picture, but here is a link to a 1963 Gran Sport drive test .
-Sam

mc25t190 · #46 01-12-2003, 10:24 PM

charlie, thats pretty cool, i drove that car when matt brought it over to the house. it ran strong, i can't wait till the 600 HP. comes out, GMMG superstock ZL1.

ChrisS · #47 01-13-2003, 02:25 AM

All 5 of the original Grand Sports are scheduled to be exhibited together this March at the Amelia Island Concours.

Chevy454 · #48 01-13-2003, 12:26 PM

<blockquote><font class="small">In reply to:</font><hr>
IMO, 600 hp. will get a lot of attention when even more people become aware of the fact that they exist,IMO.

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I think the cars will get attention, but I'm not sure who will be the most attentive: the collectors or the parts guy! Not being negative, but from my limited experience with our late models and those of some friends, I don't see how the tranny or the rear even stand a chance! Tranny problems are frequent, and the little 10 bolts are weak enough even without further weakening it with a set of gears. I've seen cars with only !free mods be hard on parts, so I can't even begin to fathom what the phase IIs or phase IIIs will break! 600hp...it's not WHAT will break, but WHEN! [img]/ubbthreads/images/icons/grin.gif[/img]

<blockquote><font class="small">In reply to:</font><hr>
Regarding warranty on the '69 COPO cars, we had no problems at all. Right from the begining I had ring sealing issues and the engine got re-ringed under warranty.

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Keith:

You are one of the few who I have talked to that had any luck with warranties on these cars when new...maybe you got better treatment in Canada? Or maybe part of it was that the warranty problems I know of are associated with Yenko cars, and the dealers weren't really sure if Yenko or Chevrolet was doing the 427 cars. Our car and another Francis Chevrolet car both sat for a while trying to get cylinder head problems fixed.

GRB · #49 01-13-2003, 02:29 PM

Those pumpkins are going to blow like they have a stick of dynamite in them. Their only salvation will be the fact that the typical owner of these cars is far less likely to "abuse" them than the typical Camaro owner.
From what I hear the trans is pretty tough.

Chevy454 · #50 01-13-2003, 03:10 PM

They sell a girdle for the 10 bolts, which seems kind of like a band-aid to me. From what I've heard, most of the fairly serious guys get a Moser 12-bolt and be done with it. All I know for sure is that the 10-bolts in the Camaros (mine included) seem to be hard on bearings.

As for the T-56 being "tough", I don't know...my SS is on it's 3rd gear set, and I know of a couple of other manual cars here in the "woods" that have had problems. But, I've also seen some power adder cars run them with no trouble, so who knows. And, the new 500hp Viper is using it, so someone has some confidence in it! I'm not up on the auto cars, but I hope the 4L60E is tougher than the 4L80E that I had in my truck...2 rebuilds in just over a year. A manual tranny soon followed!

Dedicated to the Promotion and Preservation of American Muscle Cars, Dealer built Supercars and COPO cars.