Real Horsepower of Muscle Cars

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justcuz

justcuz

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Plenty of people know that the horsepower ratings of 60s and 70s muscle car engines were deliberately set lower than what they actually could run on an engine dyno - usually for insurance reasons and so the cars could run in a more favourable class in drag races.

Auto journalist Roger Huntington wrote an article about what these engines actually put out, and here is the list. The figures are for gross HP though, I have the list of net HP ratings too.


Engine------------------Advertised----Rated----------True
------------------------HP @ RPM---- Torque@ RPM-- HP @ RPM

Buick 455 Stage 1-------360@5000----510@2800------420@5400
Camaro Z/28 302--------290@5800----290@4200------310@6200
Chevelle 396 L-78-------375@5600----415@3600------400@5600
Corvette 427 L-88-------430@5200----450@4400------480@6400
Mopar 340-4 bbl---------275@5000----340@3200------320@5600
Mopar 440-Magnum------375@4600----480@3200------410@5400
Mopar 440 Six-Pack------390@4700----490@3200------430@5600
Mopar 426 Street Hemi---425@5000----490@4000------470@6000
Mustang Boss 302--------290@5800----290@4300------310@6200
Ford 351-4 bbl Cleveland--300@5400----380@3400------340@5600
Mustang Boss 351--------330@5400----370@4000------360@6000
Mustang 428 Cobra-Jet---335@5200----440@3400------410@5600
Mustang Boss 429--------375@5200----450@3400------420@5600
Oldsmobile 455 W-30-----370@5300----500@3600------440@5600
Oldsmobile 350 W-31-----325@5400----360@3600------350@5800
Pontiac Ram Air 400------366@5100----445@3600------410@5600
__________________________________________________ __________

-The most underrated was probably the 428 Cobra Jet engine... its official rating of 335 hp was a joke, especially considering that the 390-4 bbl engine was also rated at 335 hp.

-The second most underrated was probaby either the Mopar 426-Hemi or the 340-4 bbl.​
 
Car Craft just did a shootout using stock motors with headers. I think it was the Chevy 302, Ford 302 Boss, and Ford 351 Boss. It turns out they made the advertised Hp at the advertised Rpm, however when they increased the RPM they made much more and I think the results were similar to the list posted.
 
A stock 340, even the vaunted 68 4 speed cammed, makes power to 5600... not any I've ever seen.
 
We just had a good thread about the 340 and how much it is upgraded from a 2 b 318 heads, cam, int, ex compression etc and then gets only 45 more HP... well mine sure runs strong and many I have rode in and the NHRA rated mine back in 78 at 325 hp factoring.


Thanks for the post:)
 
I'm real familiar with the Chevy big block. Ain't no way no how an L88 is gonna outpower a Hemi. I mean, the L88 was a badass, but the Hemi had it all over the big block in the induction and head department. I just put together this 454 short block the other night goin in this number matchin LS5 Chevelle I'm workin on. Roller motor. Probably gonna be around 575-600 HP but I've done lots of mods.
 
All that was back when gasoline was actually measured by octane and it hadn't any additives like today's crap. I remember in 1964 clipping the wire at the Sunoco pump to get 100 octane for my car, everyone did it
 
I think the DZ302 is still gettin low-balled on it's numbers.... Give me a break, you could get 2-4's on that b!t(h....
 
HotLines said:
All that was back when gasoline was actually measured by octane and it hadn't any additives like today's crap. I remember in 1964 clipping the wire at the Sunoco pump to get 100 octane for my car, everyone did it
Click to expand...

Hi,

What does this mean, clipping the wire?
 
Rice Nuker, back in the 60's on the east coast Sunoco used this contraction so persons can choose their octanes not that 260 or 280 were the actual number octane but there was a wire which stopped the customer from going past 240, so some clipped it
images
 
Greenhornet back in the early 80's I had a 1969 DZ302 with the cross-ram setup and was dynoed @ 450hp in stock form. I sold the car in 83 I believe can't remember exactly when but I have gone through many HP cars of all makes and models. And yes everyone who knows me says don't ya wish ya still had this or that..
 
HotLines said:
Greenhornet back in the early 80's I had a 1969 DZ302 with the cross-ram setup and was dynoed @ 450hp in stock form. I sold the car in 83 I believe can't remember exactly when but I have gone through many HP cars of all makes and models. And yes everyone who knows me says don't ya wish ya still had this or that..
Click to expand...

Yeah, that was my point... No way that DZ302 made 290 or 310hp, maybe with 3 plug wires pulled...
 
I agree about the DZ302 Chevy. Remember too, that 290 HP was advertised at 5800RPM. Them engines were built to twist 8K. No tellin what they made at that RPM. those engines were built to breathe at high RPM. There's a guy in Baldwin county "supposedly" has a LOW mileage '69 DZ car with the crossram setup and headers still in the trunk that were never installed by the dealer. I hear he shows it in locak shows around the Milledgeville, Georgia area. Only about 17 miles from me. I have yet to lay eyes on the car, though. There ain't a prejudiced bone in my bodywhen it comes to cars and I readily admit a soft spot for Chevys. I've owned and built a lot of them. They are some great engines. Quick, easy and cheap way to get into hot rodding. I would rather see a kid build a Chevy outta necessity, than a rice rocket any day. They all built some cool muscle back in the day. Saw a 78 Trans Am yesterday. Was real clean and a nice lookin car. Kinda always pined for one of them, too. Most Mopar guys and gals I know are like me. They like everything.....but it's really funny most people who like other makes sure aren't like that with Mopars. I reckon they're just jealous.
 
My old retired machine guy has a red '69 DZ302 Z-28 stuffed away in his garage, I bet the car doesn't have 10,000 on it, said he drag raced it a few years and it's been sitting there ever since... A lot of muscle cars are still out there hid in garages, sheds and basements..
 
There sure are still some out there....but not like there used to be. I gotta friend in Perry, Ga. who bought a new Challenger and rolled it in his shop. It's up on blocks for long term storage. That car will likely end up bein like that one day.
 
I've been trying to track down a '68 hemi cuda legend for 30 years that used to be in my area.. It was nothing but street racing around here back in the 70's and 80's... All my uncles were into chicks, weed, fords and chevys so I always got very few mopar storys out of them.. One reliable mopar sorce did verify he had seen the hemi cuda street race in the early 70's, he said it was one bad SOB...
 
Are you close to Charlotte? I have a real good friend from there who works for the local Chrysler body shop parts department here in Macon now. He used to have a '74 Yellow Challenger back in the day that had the first roller cam setup in the Charlotte area on the street. That car had a really nasty reputation.
 
I don't see 450HP out of a stock dz302. maybe 310- 325 at the upper rpm range.
 
Ya talk about the 70's and 80's but I did alot of street racing back in the early 60's and before I was out of my teens I had a 57 Chevy business man's coupe with a 6:71 blown 301 which is a 1/8" over 283, a racer brown roller cam and a Vitar engineering hydro. Some may find this hard to believe but my shifting points were between 87 and 9200 rpm and the engine was checked for bearing wear monthly. That was then and this is now, I am a free hand pinstriper who has been around cars all my life and started striping at 9 years old.

I too have a soft spot for Chevys as well and anything that scoots. I have a rebuilt 60 over 95 LT1 engine which makes 360 cu.inches sitting in my shop with a T56 6 speed attached. what I may do with it will peeve persons here but life is too short to play games both political and otherwise, I don't bench race or play games

mike devore, that's what it was and that's what it is. Guess it depends on where you were in 1969 whether in a carriage or driving a DZ302
 
Here's a nice read on the Chevy 302. Remember, the 290 HP rating was with one carb and severely underrated. Even on the Desktop Dyno it makes well over 350 HP. Addin in the two carbs slams it over 400 HP. It's all a guess though, because the Desktop Dyno has no provision for guestimating the effects of the crossram. I think 450 is not unreasonable, but I ain't arguin about it. It makes for some fun bench racin though.

http://www.holisticpage.com/camaro/camaros/302.htm
 
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