You're not waisting anybody's time. If you were, I wouldn't have bothered to post in the first place. I'd be off doing something else. Yes, the L88 was a "special" car. They were built specifically for racing and VERY few of them were sold to the general public. 80 in 1968 and 116 in 1969. Discontinued in 1970. In fact, they were purposely UNDERATED at 430HP so that people would want to buy the "higher" powered 435HP L71 engine. So, they are very rare and a true L88 is very expensive.

Welcome to the forum. I apologize. I did not mean to make you feel foolish.


[Modified by 79MakoL82, 5:08 PM 5/11/2002]

 

Almost all of todays crate motors are rated gross just like in the 60s and early 70s. A zz430 is rated ate 430 gross that will be about 330 at the rear wheels based on actual dyno numbers. My 383 rates about 390 at the rear wheels and based on rides I have given to BB vette owners including L-88 owners is wow :eek: . They can't believe that a stock appearing small block will beat their big blocks.

What is great about the Fast Burn heads is that you can run the stock vette valve covers with roller rockers.

 

As already posted, both engines are rated at gross hp. Also as already posted, the L88's 430 hp rating was bs. GM didn't lie, they just played the same game that they played with other engines and chose a point on the power curve that suited their purpose. In the case of the L88, they chose to advertise the hp at a point that was about 1,000 rpm below it's peak. They did the same thing when they rated L78's at 425hp in Corvetttes and Impalas but at 375hp in Chevelles and Camaros by chosing a figure below peak hp. The initial batch of L72's were rated at 450hp but they chose to change it's rating to 425hp and just advertised it's rating at a lower rpm.

 

Chuck, yes, I aked quite a few people that very question before buying the ZZ3 I had installed in my 68. It's 345 HP is net; that is, it was measured on a dyno with all accesories, headers and 3-inch exhaust. I believe this info was in the GM performance parts catalog. This makes sense, since my RWHP was 290, very close to what the 97-2000 C5s put out with LS1s rated at the same 345 HP.

That's why I believe the ZZ502, if rated gross as the L-88 was, would be cranking out over 600 ponies. Not only are the ZZs more potent, but they are much more efficient than the L-88s of old.

 

Dave68,

I'm still not so sure. 69ttop502 has the 502 Mark V motor and his high number was about 340rwhp with open headers. I would expect his net hp to be pretty close to 400. The following is the test on his engine:
________________________________________ ______________________
Car: 1969 Corvette Engine: GM 502BB, Iron rectangular port heads, hydraulic cam/220 duration@.050 and .500 lift, 8.75 to 1 compression, low rise LS6 intake, holley 750 double pumper carb, and Hooker Sidepipe Headers. Tests are RWHP figures 1/5/2002
Base: Mufflers, HH reverse flows. 246.7 HP/388.9 torque.
2nd pull: Mufflers/ baffles, Spiral Turbo Baffles (4"). 338.5HP/408.8 torque. An increase of 92HP and 20Lbs. Ft. of torque.
3rd test: Sidepipes, no mufflers or baffles. Wide open tubes. 342.4HP/445.1 torque. Thats a high bolt on increase.
This particular engine needs more cam and head work, suggested by Romar, Ent. after testing was complete. Romar felt with these modifications, getting power in the 550+ range would not be difficult.
________________________________________ ______________________


To be sure, the Mark V's are fantastic engines very capable of putting out massive power in the 600+ range. But they will take a little help from stock to get them there. A simple cam change would make a huge difference.

Chuck

 

Chuck,

The 502 I was referring to is the 502/502, not the ZZ502 (sorry) that pumps out 450HP. Of course, the 502/502 Ram-Jet pumps out 502 HP and 565 lb-ft of torque at 3200 RPM and lists for $8800.

However, the L-88 was an extra $3000 or more back in the 60s, so $8800 seems like a real bargain in today's money.

 

Dave, FWIW the L88 option listed for 950 dollars in 67/8 and 1050 in 69. I believe you are thinking about the ZL1 option which was a 3K upgrade on the L88 option.

 

ZZ502 is 502/502hp with 567 torque:
http://www.sallee-chevrolet.com/Chev...s/502hpek.html

The 450hp version is called the H.O.502:
http://www.sallee-chevrolet.com/Chev...V8s/502ho.html

 

That may very well be true. However, that amount ended-up being a good 20-25% of the car cost.

 

67Heaven,

Do you know whether the power quoted is Net or Gross? The place selling them from your link shows dyno testing for $450 to confirm the power. The picture shows the motor with open headers and dyno powered water pump, so I still looks to me that the figures quoted are gross horse power. The cam specs and compression also suggest these to be gross figures too. Basically it appears to be a mild 454 with 50 cubes more.

This looks like a great combination. Huge power and very streetable.

Chuck

 

Okay, I had to go check my GM Performance parts catalog to verify what I thought. The description of the ZZ3 engine included: "These 350 engine with Quadrajet carburator, 1 3/4" headers, and low restriction mufflers produced 345 horsepower(at 5250 rpm) and 387 lnb-ft torque (at 3250-rpm). Granted, an alternator is not mentioned, but that would not act as a large parasitic loss on an engine as potent as this. Remember, my 68 was putting down 290 HP at the rear wheels. If the 345 HP were gross, I think that the RWHP would be quite a few ponies less.

What I mean to say is that the net horsepower may depend heavily on what year C2, 3, or 4 in which you will drop it. Chevy is not going to test all their crate engines under every possible accessory-loss scenario, so if you're going to drop the ZZ engine in a 60s car, you'll end-up with a net horsepower that is very close to GM's ratings. Throw a whole bunch of parasitic accessories on it and the net HP will drop proportionately.

Does all that make sense?

 

Dave,

I agree with you that the alternator and water pump wouldn't account for a major difference, perhaps 10 horse power. I think the biggest loss between the net and gross rating is exhaust manifolds and intake air temperature. For Gross numbers, the air temp is about 70 degrees F. Net ratings showing under hood temps are much higher. There is a 1% difference in hp for every 7.5 degrees (usually rounded to 10 degrees) change in intake air temperature. This is why the cols air hoods are so good. The cold air hood on the L88's was said to reduce the 0-140 mph time by 7 seconds.

Real life under-hood temps can be horrendous! I don't recall what temp is used on the net ratings. I also agree with you that for advertising purposes, they probably quote gross because they don't know what kind of car the engine is going into. Like you said, if it's a Corvette with headers, JCL baffles, and a cold air hood, and no power accessories or comfort items, the difference between gross and net should be pretty small. If going into someone's loaded Monte Carlo with factory exhaust, the difference would be much, much larger.

In any case, you are right that the ZZ engines give a lot of bang for the buck in a very streetable package. A 500+ ZZ engine would deliver approximately the same power much more effortlessly than my high strung L88. Funny in that I bought the L88 because it made a little more power more effortlessly than my dual quad small block :)

Chuck

 

Although I won't likely go that route, Chuck (and yes I said it earlier), I'd prefer 12.5:1 and an idle to rattle your fillings by.

Sure I'll go ZZ502, but I'm thinkin' L-88 :jester

 

Pull out the pandoras box...I'd love to see a dyno from a STOCK L-88...BTW: Here is a site of interest: http://home.golden.net/~appster/text.march.html :cheers:


[Modified by Mr turbo rotary, 12:23 AM 5/13/2002]

 

Chuck,
My bone stock (when newly installed) ZZ/502 dynoed out at 420 RWHP with open headers.
:yesnod: :chevy :chevy :yesnod:

 

You are quite correct, sir......
:yesnod: :chevy :chevy :yesnod:

 

Chuck,

I didn't mean to "undervalue" your L-88. It is certainly worth a princely sum of money. I went from a 327-350 HP (gross-rating) engine to a ZZ3 and there was NO comparison. The ZZ made the 327 feel like it was actually a V6 engine.
I estimate that the ZZ was cranking out a good 70 HP more (net) than the "old school" V-8. I can't imagine what a 502 or L-88 would've felt like, although the weight distribution of a C3 with small block (especially one with aluminum heads and intake) is real close to 50-50, so handling would probably suffer somewhat.

 

Okay wait a sec.
The 502 crate motor is still intended as a street motor and is not built for racing like the 427 L88 is. Now, build the 502 the same as the 427, and yes, I would agree, the cubic inches would rule the day. Then you have an apples to apples situation there.

However, a full race motor like the L88 against a 502, I do not believe the 502 would prove any superiority. The estimates I have seen for the L88 have it making around 585 hp and somewhere near that for torque. The 502 makes the same kind of torque, in a much more streetable engine, but the hp is not up to the level of the L88 race motor.
And yes, that's good old fashioned Gross horsepower for those crate motors, not net.

How are they gonna advertise net hp figures without the crate motor being in a car or having accessories bolted on? You purchase the crate motor with the hp/tq capabilities taken at the crank, kind of like they did back in the 60's.

But you can't even trust those numbers from the factory, because they all played this horsepower game. GM said the L88 made only 430 hp. That was a patent lie, because of the rabid insurance industry and government safety mongers. Likewise, the 426 hemi, 428 Cobra Jet, 455 Superduty, among other great street-running race engines, were also grossly underrated.

The 502 would make its torque at a lower rpm and would be a much easier engine to live with on the street. And when compared to a street-going 427, yes, the 502 would be stronger...but folks, the 427 was last built in 1969. That is 33 years of technological progress.

For that matter, every one of those technological advances can be applied to a 427 built today to build one street-worthy with lower compression that still makes L-88 power numbers. However, the 502 would still have more torque under the curve with an equivalent build up. It depends on what you want. A 427 is a great motor too...a 502 is not for every body and every purpose. I just built a strong 427 myself, and I kind of doubt if a 502/502 is gonna outpull me. But we'll see one of these days.

Let's keep out of the apples and oranges arguments and keep it apples and apples.

 

Mr Turbo Rotary, there was a thread a couple of weeks ago of a dyno test of a STOCK L88 and it put out 465hp with exhaust manifolds and 540hp with open headers. P.S. the owner also said that he may have done better with timing and jetting adjustments. Pretty impresive for 35 year old technology :cheers:

 

SBR, Chuck Harmon was nice enough to e-mail me the dyno etc. The car produced 465 hp at the crank which is 371 rwhp in stock form with a cam. With factory headers the car produced 538 hp which is 430 rwhp. Now this engine produced slightly more hp than the L-88's from the magazine dyno #'s on the corvette archive. They produced 500 hp to 521 hp which equates to 400-415 rwhp. I believe Bad L-88 had a cam...I have yet to see a higher hp stock 60's-70's muscle car.. :cheers: