Chevrolet Yenko Camaro specs

@fastestlaps please delete all these Yenko cars, they are all tuned.

@ Viking: My father own Chevelle SS with LS6 engine has power about 360 Hp. But my father succeed create his Chevelle into 450 Hp and 500 ft-lbs without using any racing part. He just change his piston ring, intake and exhaust into modern component from edelbroc performance.

I believe that dynojet chassis dyno operation with all corrections put in give useful and repeatable numbers(lower numbers than without the corrections). I think the drivetrain losses for a manual trans with independent rear is 16 percent, 12 percent with live axle. Drivetrain losses with an automatic are 22 percent with independent rear, 18.3 percent with live axle. These estimates are for front engine rear drive vehicles, and others might disagree a little with my correction numbers. As for dual clutch, and all wheel drive, I have no idea on a correction formula as yet.

I guess while I am at it. Looking at reputable dynojet numbers, I estimate the following. The Ford big blocks 427, 428, and 429 would all be rated at no more than 315 net hp. Not to be labeled a Ford hater, I think that the Chevy LS-6 454 SS would be rated 345 net hp (as opposed to the 450 hp gross rating.). A perfectly restored Chevelle SS 454 LS-6 with 3 speed auto got 283.25 RWHP at 5600 rpm as tested by Super Chevy magazine.

@Super8 the L88, ZL1, and this L72 were all underrated by the gross hp standards of the day. With no accessory drives, tuned headers, no mufflers, no air cleaner, etc. as allowed under SAE gross standards these engines produce roughly 550, 560, and 450 hp (gross) respectively. However, converting that gross hp into modern style net at the crank, with all parts as installed in the car on the showroom is difficult, but not impossible. The 376 hp quoted for the ZL1 is the net hp. I believe the L72 engine would be rated at 325 hp net.

@ Viking: Chevy did a great job in Yenko Camaro, also the ZL1. According to some source, 376 Hp in 1969 ZL1 is not too legit. Some people claim have 425 Hp on their ZL1 but still it's questionable. Corvette L88 and ZL1 also had questionable horsepower since it's not their real horsepower to fool insurance company. Some said it has 530 Hp for L88 and 580 Hp for ZL1. That might be true power that given from GM. You can search it in here:
http://www.automobile-catalog.com/

Super Chevy magazine took several completely stock perfectly restored muscle cars to a dynojet in North Carolina to find out the real stock power. A Yenko Camaro was one of the cars tested. The result? Lots of power for a car available in 1969! Rear wheel power: 287.56 at 5300 rpm, and rear wheel torque of 319.71 at 3500 rpm. Very nice power band throughout, it was still making 285.29 rwhp at 5900 rpm! Comments?

So okay how much power does this mighty engine really make in modern terms? Well SAE gross ratings are not a good indicator, and it isn't practical to try and re-rate it directly into modern SAE net. I think the availability of dynojet chassis dynos to give a rear wheel horsepower figure is the best alternative. Sure there are different shops, conditions, and operators, so one dyno sheet isn't perfect to compare to another, but if you look only at SAE corrected ones it isn't that bad.

Since some of the younger members have in my opinion a slightly inflated view concerning the actual net horsepower of the great cars of the sixties, allow me to give a view on the cars of my youth. There are at least four muscle car engines that got underrated by the factory in the 1966 to 1971 gross hp era. The 426 Hemi, the 428 Cobra Jet, the 427 L72, and the 427 L88/ZL1 family. The Yenko Camaro has the L72. This engine was introduced in the 1966 Corvette with a 450 hp rating that due to new insurance premiums got almost immediately down rated to 425 hp.