ZR-1 Street Skinner

[Paul Workman]

Originally Posted by tcz062

Question, why does it not matter 2 or 4 bolt ? The 4 bolt mains were stronger bottom end ? Is that not why L82's are more disreable than L48's ? Getting educated so I can make the correct decision on my offer.

To think of the "two bolt mains" in LT5 in the context of a SBC is "apples to oranges". In the first place, the main bearing caps of a SBC stand alone as individual pieces, held by 2 or 4 bolts achored in the block.

The LT5's main caps are moulded into a separate girdle or "ladder". The head bolts for a "two bolt" 90 LT5 are huge - approx. a foot or so long - and together weigh over 20#!!

The bolts do double duty. They sandwich the block between the heads and the a girdle (ladder-like) section into which the main caps are mouled. Thus thrust on the heads is directly transferred to clamping force of that girdle (and with it, the main caps) to the block - a truly inspired engineering concept.

The four-bolt LT5 block has auxillary bolts that are short and anchor into the block itself (vis-a-vis SBC method) - part of the 405 hp upgrade "to better stabilize the main caps" (Heart Of The Beast). Both the long head bolts AND the short aux. bolts are smaller in diameter than the 2-bolt motor's bolts (Marc Haibeck explained in a post over a year ago). But, as far as strength goes, (again from Marc) there's really little practical advantage in terms of reliability or other apparent advantage between the 2 vs 4 bolts.

Case in point, There are a few 427 & 441 cid 2-bolt, 10-second cars roaming the country that are making around 700 chp and turning over 7500+ rpm with no problems. So, again, the SBC and LT5 in the context of two vs. four bolt mains have no comparisons, and both LT5 motors can be upgraded to big hp w/o the kind of concerns one would have with a SBC upgrade. Except for cases where the LT5 has been "sprayed" too much, the bottom ends don't break (apparently).

Anywayz... 2 vs. 4 bolt is apparently NOT a practical issue in actual use/practice, mechanically speaking.

P.

[WARP TEN]

Originally Posted by tcz062

Sorry no photos. He said the street skinner package was done around 10 years ago, ported and polished heads, new valves, cam timing, ported plenum,ported fuel injector housings, 409's, power effects exhaust, testing was 475 HP, 94 chrome wheels. The paint looks great, under carriage spotless, seats look like just they did on day one. Windshield looks perfect. Some of the door molding looks a little dry. The car it looks better than my 92 that has 29,000 miles.

Looks to me like a Corsa exhaust not Power Effects but that is arguably better for you anyway.--Bob

[tcz062]

That explains the bottom end, learn something new everyday. The exhaust is adjustable power effects he has two sets of tips, the stainless on the car and a black powder coated set. They bolt on with 4 bolts on each side.

[Kevin]

i coulda sworn the PE tips were more oval but they are a fantastic sounding system. i'd love to find a set up

[Hib Halverson]

"Street Skinner" engine packages have been a product of Automasters of Bowling Green" or just "Automasters" when the business was in California. The first ones were done in the 91-92 period and they were done on a variety of different ZR1s from 1990 models to 1995s. Each one was a little different but included a "standard" core of engine mods: ported/polished heads, ported/polished housings, partially ported/polished plenum, reset cams and custom cal. Most Street Skinners were 350s and the performance of those varied from 475 to 530-hp SAE depending on whether or not the engine had stock manifolds and cats or headers and what kind of cat-back exhaust it had. Also some of the later Street Skinner 350s made a little more power as the package was developed over time.

Not sure how many Street Skinner engine enhancement packages were done nor am I sure how many were 368s, but the guy whose shop does them is Jim Van Dorn. He may know something about the history of the car in question.

Van Dorn can be reached at jim@automastersofbg.com

[tcz062]

That is a great deal 12.5, you could not find a late C4 as nice as this street skinner at that price here.

The black powder coated tips are more oval shaped, they are all aluminum.

I did call JVD, the guy showed me the receipts for all the work on the car. He said they did between 30 and 40 of these. He said he has a 90 for sale at 26k. Can't remember all the details but he said it was a Street Skinner.

[vandornjim]

Originally Posted by Hib Halverson

"Street Skinner" engine packages have been a product of Automasters of Bowling Green" or just "Automasters" when the business was in California. The first ones were done in the 91-92 period and they were done on a variety of different ZR1s from 1990 models to 1995s.
Van Dorn can be reached at jim@automastersofbg.com

Hey guys! I thought I heard somebody mention Pirate!
Back in the day, Rippie did his Black Widows. There were 8 done. Mine was the last. After that, I got a call from Mercury that mine may not have been as good as it could have been because they were under pressure to "shut off" the LT5 program ASAP. I was offered the opportunity to return the heads for a better look at a later date, which I eventually did. What we found was a tremendous gain in flow characterisitics with a fresh look at how we did the porting. When we reassembled my engine, it was incredibly better. Very smooth ad powerful acceleration from 5,000-7,400 rpms.
We decided to develop this new procedure and offer the package which was whatever the customer wanted. Porting, headers, powder coating, prom and custom cam timing, etc. We didn't mess with the durable bottom end because there was no need.
We named the package "Street Skinner" after the "Snake Skinner" which was much less horsepower than our package.
We did approx 30-40 packages and to my knowledge, all are still in service.
There are some great buys out there!

[tcz062]

Thanks Jim, I have talked to a few guys that have experience with the Street Skinners. I was told that a car that has documentation from your shop, the value of that car is significantly higher. They also told me that a few of your cars had been totaled in wrecks. They said there were magazine articles written about a few of the cars you did, maybe you know more about those.

[vandornjim]

Originally Posted by tcz062

Thanks Jim, I have talked to a few guys that have experience with the Street Skinners. I was told that a car that has documentation from your shop, the value of that car is significantly higher.

Well, some say enhancements are not necessarily investments, but in this case, doing a well engineered porting package with some significant HP increases, without sacrificing anything in return, what's to lose?

They also told me that a few of your cars had been totaled in wrecks.

I told them to do the brakes too!

They said there were magazine articles written about a few of the cars you did, maybe you know more about those.

I think Motor Trend April '94 was one. They said it was "by far the fastest Corvette we've ever tested". Imagine that. And then look at the Corvette of today and tomorrow. There sure seems to be alot of today's cars being wrecked. Too much titanium and not enough cranium....

The ZR-1 did it's job. It revolutionized GM's engineering. It's also a steal of a bargain right now. You can buy a car, put $10K in HP, brakes, exhaust, & service items, and have a sweet car for $25,000.

Is your key on?

[tcz062]

Thanks Jim, I read the article. Very interesting, was not aware that you were the one that named the black widow. I new a guy that lived in Fort Morgan Co that owned one of the eight for a while, it was a dark maroon colored car. Now I think I going to have to buy that 93 if I can get the right deal.