Factory 425HP 396 ??? - Chevelle Tech
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post #1 of 30 (permalink) Old Apr 20th, 00, 1:09 PM Thread Starter
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I found a guy to rebuild my Posi-unit for me and assist with a gear swap. He is a GM mechanic with about 15-20 years experience.

He swears up and down that he has an original matching #'s 1968 Camaro with a 425HP 396 - but no docs. I told him that I was fairly certain GM only put that engine into a Corvette and that it could not be ordered for a Camaro or a Chevelle.

So, the next day he says he asked another guy at the GM dealership and claims this guy looked it up (in some reference book) and verified that a '68-'69 Camaro could be ordered with this motor.

My understanding was that the only Central Office Production Order for a 425HP motor in '68 or '69 would be the 427, but he swears it is not a 427.

Can anyone tell me if this motor was ever available in anything outside of the Corvette? Please point me to a reference if you can ... If he is correct, I want to buy that car from him before he has a chance to begin the restoration!!

P.S. Is this the L-89 option and would it have to have aluminum heads?

Thanks, guys.

------------------
Stan Hanek
'66 SS - 396 4 sp.
http://www.chevelles.com/showroom/Stan3.jpg]

[This message has been edited by Stan (edited 04-20-2000).]

[This message has been edited by Stan (edited 04-20-2000).]
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post #2 of 30 (permalink) Old Apr 20th, 00, 1:29 PM
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396-375 is the same as the 396-425, only difference is the 396 was rated 425hp in the corvette because of better performing exhaust manifolds. So I guess you can call it what you want but it's only 375 HP in the Chevelle, Camaro and Nova. ( at least on paper)

Rick

[This message has been edited by RickinNC (edited 04-20-2000).]
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post #3 of 30 (permalink) Old Apr 20th, 00, 2:14 PM
Cam
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I agree that the L78 had different ratings in '65 vs. '66 - '70, but it was the same engine. What's funny to me is that manifolds would affect gross h.p. ratings; I thought they would only affect net ratings. BTW, wasn't the L72 (427/425) labelled as 450 h.p. on Yenko Camaros? I've also heard the L72 automatics were about 410 h.p. There's engineering (which the mark IV had) and there's a politically-motivated fudge factor (thou shalt not exceed 1 h.p for every 10 lbs.).
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post #4 of 30 (permalink) Old Apr 20th, 00, 3:17 PM
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I will have to agree with everyone here and say that the 396 in the 'Vette and the Camaro, Chevelle, & Nova were identical...except for the exhaust manifolds and the hp ratings. I would have to guess that is what the guy is thinking of.

As far as the Yenko Camaros hp rating, ALL of the '69 COPO cars were rated at 425 hp from Chevrolet, regardless of transmission. The 450 hp rating came from the NHRA whenever they had to index the cars. Kind of makes you wonder about the other GM hp ratings, huh?! There were some early ('67 & '68) Yenko conversion cars that were automatic and carried a 410 hp rating, which is where a lot of confusion on the Yenko hp ratings begins.

------------------
Rob Clary
'70 LS-6 Chevelle
Team Chevelle Gold Member #85
Interested in COPOs, Yenkos or other dealer built muscle cars then go here: www.yenko.net



[This message has been edited by Chevy454 (edited 04-20-2000).]
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post #5 of 30 (permalink) Old Apr 20th, 00, 3:19 PM
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You might want to post this question on the Camaros.net site. There several knowledgable Camaro people over there that may have some more input. I tend to agree with the other responses.
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post #6 of 30 (permalink) Old Apr 20th, 00, 5:39 PM
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In ' 65 the 396 hi-po was rated at 425hp. in the Corvette, and in the Big cars ie: Impala, Caprice. That's it! All other years were factored at 375hp.

------------------
1972 Malibu (1 st. car) Project waiting to happen
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post #7 of 30 (permalink) Old Apr 20th, 00, 8:21 PM
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Some people say that there were 1968 COPO 396 Camaros built with 850 cfm Holleys and 140 mph speedometers. If you look up his engine number and suffix code that should tell you what engine it is.
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post #8 of 30 (permalink) Old Apr 21st, 00, 12:12 AM
Cam
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Joe58, I heard something about special carb and a few other odeseys on a thoroughly documented '68 Yenko Camaro. As it turns out, this one was actually built by Chevrolet with the L72, not converted by Yenko. Prior to this discovery it had been accepted that the '69 were the first to get the factory 427. Still I believe that almost every '68 Yenko Camaro was a Yenko conversion, not a factory 427.
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post #9 of 30 (permalink) Old Apr 21st, 00, 8:11 AM
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CAM - There was a 68 Yenko Camaro that Classic Industries used as a sweepstakes prize. They claimed it was the "one and only" 1968 427 COPO Yenko Camaro but many people do not believe it. I was talking about the 396 that was in the 1968 Camaros as delivered to Yenko. Some people say the 396 cars had a special suffix code and was built as a COPO with the 850 Holley and 140 speedometer.
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post #10 of 30 (permalink) Old Apr 21st, 00, 10:44 AM
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Simple Chevrolet fact, in 1966, they did offer a 396/425 horse engine for their larger cars, but customers were reluctant to order the 427/425, thinknig that they didn't need the larger displacement engine to do the same work as the 396, so the R&D engineers did a fast one on the 396/425.

They ran one on a dyno, and recorded the rpms at which it made 375 horsepower, and re-certified the engine. Customers didn't question the need for the 427 after this. The rpm levels tested were 396-6800, 427-7250. Both engines were same-same except for the bore sizing.

The 396/425 was only available in 1966 vehicles for about a month, and I haven't ever come across a factory installation of one, documentation or specs on installed units. The factory might have killed the RPO before they actually installed one in a vehicle.

1965 Z16s did have different cams, hydraulic, but were performance equal to the solid lifter engines, just 50 horsepower resiricted by the stock 396/325 exhaust manifolds used to clear the Chevelle frame.

Corvettes used a cast iron 4 into 1 header (carry-over from the 396/425), and a modified version of this header was also used on Impala and Caprice in 1966, Chevelle had even a different one in 1966/1967 for the 396/375.



[This message has been edited by IgnitionMan (edited 04-21-2000).]
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post #11 of 30 (permalink) Old Aug 7th, 07, 9:59 PM
Rich
 
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Re: Factory 425HP 396 ???

I had a 1968 Chevelle SS. It was a 396 rated at 425hp. Any engine part that I would buy was always cross referrenced to a 1965 Vette eng. I did have it dyno-tuned and it did max out at 424hp. Used to street race at Skip's on North Ave. It was a great car, got drafted and had to sell.
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post #12 of 30 (permalink) Old Aug 16th, 07, 11:51 PM
Terry
 
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Re: Factory 425HP 396 ???

I bought a brand new 1969 Nova in the Lansing Illinois area. It was a SS 396/425 HP. I remember I paid $4600 and some change for the car. The 425 HP option was about $300 more than the 375 HP version. It was awesome. We put a 488 rear end in it and added hooker headers and ran 12.72 117 MPH at the US 30 drag strip. It came with a 350 open rear end and would kick into passing gear at 120 MPH and would bury the speedomener. It would run about 160 MPH. This car was Dyno tuned and appeared to have about 460 HP on the machine at Dyno Dons in Chicago. Naturally I blew it up with that 488 rear end. GM gave me another engine, but it was never the same as the original. It would only run about 14 sec in the 1/4 mile. I blew that one up too and they gave me one more and told me to never come back. What a great car. I would kill to have it today. So yes, even though its hard to find info on these 396/425 Engines, they did exist.
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post #13 of 30 (permalink) Old Aug 17th, 07, 10:54 AM
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Re: Factory 425HP 396 ???

Quote:
Originally Posted by terrybig View Post
I bought a brand new 1969 Nova in the Lansing Illinois area. It was a SS 396/425 HP. I remember I paid $4600 and some change for the car. The 425 HP option was about $300 more than the 375 HP version. It was awesome. We put a 488 rear end in it and added hooker headers and ran 12.72 117 MPH at the US 30 drag strip. It came with a 350 open rear end and would kick into passing gear at 120 MPH and would bury the speedomener. It would run about 160 MPH. This car was Dyno tuned and appeared to have about 460 HP on the machine at Dyno Dons in Chicago. Naturally I blew it up with that 488 rear end. GM gave me another engine, but it was never the same as the original. It would only run about 14 sec in the 1/4 mile. I blew that one up too and they gave me one more and told me to never come back. What a great car. I would kill to have it today. So yes, even though its hard to find info on these 396/425 Engines, they did exist.
You might want to compare the internal parts onthese two engines...pistons, cam heads valves and what not. They are the same parts for both the 375 and 425 HP engine. Yes both engines did "exist" .....because they were the same engine internally.
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post #14 of 30 (permalink) Old Aug 17th, 07, 12:05 PM
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Mike
 
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Re: Factory 425HP 396 ???

Here's an idea for a STICKY. GM NEVER sold a 425 hp (rated) 396 in anything but a Corvette and Full size and GM NEVER made a 66/67 427 Chevelle! Anybody that says different has to prove it...and they won't be able to.

Mike Murphy
1971 Chevelle SS454 (SOLD)
1971 442, #s matching, GM of Canada documented
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post #15 of 30 (permalink) Old Aug 17th, 07, 1:32 PM
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Re: Factory 425HP 396 ???

Quote:
Originally Posted by mmurphy77 View Post
Here's an idea for a STICKY. GM NEVER sold a 425 hp (rated) 396 in anything but a Corvette and Full size and GM NEVER made a 66/67 427 Chevelle! Anybody that says different has to prove it...and they won't be able to.
when Mikes right, He's right!

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