To Tell the Truth

Dan Bennett · 12-14-2011, 10:50 AM

Yes, it was a game show in the 60s but it also could be applied to the horsepower ratings the manufacturers listed for their performance cars.

There's a lot of controversy today with obviously incorrect ratings but it's really nothing new. How about your opinion on the engines of the musclecar era? Just to pass the time in the offseason here's mine, off the top of my head without a whole lot of research, and in no particular order. 71-up smog engines don't count.

I'm sorting them according to their as-produced, showroom condition. I may have some of the HP numbers incorrect as I'm working from memory.

"We'd rather have a big number for our ads"
Ford 390/335
AMC 343/280(? not sure about the HP)
Mopar 426/365 wedge
Chevrolet 350/300
Ford 351 Windsor 4V
Ford Boss 429

"That's the number we saw on the dyno (but at 4000 rpm), wink, wink"
Boss 302/290
Z28 302/290
396/375
454/450
Cobra Jet 428/335
Stage 1 455/370
Ram Air IV 455/370
Olds 455/370 W30
Mopar 340/275
327/275
440/390 Six Pack
426/425 Hemi

"We screwed up and put the right number on"
Mopar 440/375
396/325

Additions are welcome. What is the engine that had the most bogus factory rating, high or low? I suppose you could check the NHRA factors for that era but I don't have them available.

Hemi Moose · 12-14-2011, 03:55 PM

If you remember all of that just by going by your memory, well then...as for any bogus engine horse power figures, I've always wondered what the true HP figure was for a 440 six pack motor, because it could give the 426 Hemi motor a run for their money.

Paul Ceasrine · 12-14-2011, 04:25 PM

Dan,

A couple right off the bat,,,

The 1968 Ford Cobra-Jet 428/335 HP
NHRA re-factored it to 360 HP immediately, which sounds about right on..

The 1968 340/275 HP, if the Horsepower remained at what the factory
stated, the 1968 Barracuda or Dart GTS would have been classed in
G/Stock instead of E/Stock in 1968.

The NHRA re-factored the 340 to 310 HP even before the 1968
Winternationals. Again a fair HP rating.

1964/1965 Mopar 426/365 HP 'S' Street-Wedge.
Completely over-rated Horsepower,
10.0 - 1 Compression Ratio
Mild hydraulic camshaft,,,.(431/.431 Lift, w/268* duration)
Standard cylinder heads (#2406516 castings) (2.08" intake / 1.60" exhaust) (Small-port exhaust)
These cylinder heads were the same found on the 361/265 HP 2-Barrel engines
Weak valve springs
Horrible flowing cast iron intake manifold
Carter AFB rated at 575 CFM

Horsepower for the 426/365 HP 'S' Street-Wedge, rating probaby closer to 300 to 310 HP.

Scary fact;
In 1964 and 1965, the 64' Plymouth 426 'S' Belvedere and/or 'Sport Fury' ran in A/S or A/SA.
In 1966, it was classed in B/S or B/SA, versus the 66' 427/425 HP Biscaynes and 66' Galaxie 500's 427/425 HP cars.
In 1967, back into A/S or A/SA, versus the 67' Chevelle S396 396/375 HP cars.
In 1968, C/S or C/SA, against the 68' 428 Cobra-Jet Mustangs.

Talk about a 'tough challenge', they didn't stand a chance.

Dan Bennett · 12-14-2011, 05:22 PM

Paul: Your reply got me thinking. If the 340 was refactored before it ever hit an NHRA event, how did that happen? I've heard stories of how sharp the Farmer was but I doubt he'd set a factor just by reading a magazine article or two. Did he look at the specs and come pretty close to the real HP? Big difference between now and then!

Moose: I'm with you on the 440 Six Pack. The ones around here were pretty quick indeed. But I'm thinking it worked the other way with the 340 Six Pack. I don't think that engine, as produced, needed anywhere near that much carb - and that was just about the only real modification they made. Especially since they were only in the heavier E body, I'd bet they didn't want anything to do with a 340 Dart or Duster.

We had a pretty active street scene around here even though it was a small town. Two friends used to duke it out numerous times a week. Eddie had a 66 427/425 Corvette and Fred had a 66 Coronet Hemi 4 spd. Both were pretty capable with a wrench.

It was fun to watch since neither car could claim bragging rights. One car would win 3 out of 4 on the street but the other would win 3 out of 4 at the strip. I honestly can't remember which was which other than I'd bet the Corvette had the street advantage since the independent rear would squat and probably hook better on an unprepared surface.

Even though I can't remember either car winning by more than a fender, this was long before redlights and who knows about a street start. They sure were a joy to watch.

Paul Ceasrine · 12-14-2011, 06:09 PM

Dan,

340/275 HP, horsepower re-factor to 310 HP.
Not sure on how the NHRA knew, but they did.

Chrysler Performance was informed of the rating back in December
1967.
Thats when the Southern California Dodge Dealers started building
the E/S Dart GTS that Bill Shrewsberry raced.

The #3150 lb. 68' 340 Dart GTS and 340 Barracuda's still were successful in E/S and E/SA, running 12.80's.

Imagine them running in G/S in 1968,,,,,,,

Chris Barnes · 12-14-2011, 06:46 PM

I know we're supposed to be talking about racing here but I just have to say that the Mopar Six Pack option is one of the things that make America great. It is just the most stupid good fun ever put in a street car. Anyone who's ever driven one on the street knows what I'm talking about--those outboards are vacuum activated insanity!!! I'm too young and weak to have driven one with drum brakes but even still whoooooo!!!!

Chris Barnes
Wagons of Steel
Stock 6621

Dan Bennett · 12-14-2011, 07:26 PM

Quote:

Originally Posted by Paul Ceasrine

Dan,

340/275 HP, horsepower re-factor to 310 HP.
Not sure on how the NHRA knew, but they did.

Chrysler Performance was informed of the rating back in December
1967.
Thats when the Southern California Dodge Dealers started building
the E/S Dart GTS that Bill Shrewsberry raced.

The #3150 lb. 68' 340 Dart GTS and 340 Barracuda's still were successful in E/S and E/SA, running 12.80's.

Imagine them running in G/S in 1968,,,,,,,

Paul,

OK, that makes more sense now that you give the dates. In December 67 the 68s would have been on sale for a few months.

As crazy as things were back then, I wouldn't be surprised if one of the competing manufacturers got access to a 340 and made sure that NHRA Tech was aware of the numbers the car ran. Just as a courtesy, of course.

Arnold Greene · 12-14-2011, 07:44 PM

Quote:

Originally Posted by Paul Ceasrine

Dan,

A couple right off the bat,,,

The 1968 Ford Cobra-Jet 428/335 HP
NHRA re-factored it to 360 HP immediately, which sounds about right on..

The 1968 340/275 HP, if the Horsepower remained at what the factory
stated, the 1968 Barracuda or Dart GTS would have been classed in
G/Stock instead of E/Stock in 1968.

The NHRA re-factored the 340 to 310 HP even before the 1968
Winternationals. Again a fair HP rating.

1964/1965 Mopar 426/365 HP 'S' Street-Wedge.
Completely over-rated Horsepower,
10.0 - 1 Compression Ratio
Mild hydraulic camshaft,,,.(431/.431 Lift, w/268* duration)
Standard cylinder heads (#2406516 castings) (2.08" intake / 1.60" exhaust) (Small-port exhaust)
These cylinder heads were the same found on the 361/265 HP 2-Barrel engines
Weak valve springs
Horrible flowing cast iron intake manifold
Carter AFB rated at 575 CFM

Horsepower for the 426/365 HP 'S' Street-Wedge, rating probaby closer to 300 to 310 HP.

Scary fact;
In 1964 and 1965, the 64' Plymouth 426 'S' Belvedere and/or 'Sport Fury' ran in A/S or A/SA.
In 1966, it was classed in B/S or B/SA, versus the 66' 427/425 HP Biscaynes and 66' Galaxie 500's 427/425 HP cars.
In 1967, back into A/S or A/SA, versus the 67' Chevelle S396 396/375 HP cars.
In 1968, C/S or C/SA, against the 68' 428 Cobra-Jet Mustangs.

Talk about a 'tough challenge', they didn't stand a chance.

Except the 375/396 Chevelles were rated at 425/hp, while the 427 Fairlane was rated at 410, and the 427/425 Biscayne was another issue. Talk about not standing a chance.

Paul Ceasrine · 12-14-2011, 08:27 PM

To Tell The Truth,

The whole batch of 'B and' RB' engines had over-rated Horsepower
figures from the factory.

The 383 (330 and 325 HP engines) were much closer to 275 Horsepower.

The 383 (335 HP Road Runner and Super Bee engines) were much
closer to 290 Horsepower.

Of course the 68' 440 cylinder heads, camshaft, valve springs and
exhaust manifolds were worth an additional 15 HP.

The 426/365 HP 'Street Wedge', closer to 300 HP.

The 440/375 HP, still high,,,,,,,more in-line with 360 HP.

Dan Bennett · 12-14-2011, 09:39 PM

Quote:

Originally Posted by Arnold Greene

Except the 375/396 Chevelles were rated at 425/hp, while the 427 Fairlane was rated at 410, and the 427/425 Biscayne was another issue. Talk about not standing a chance.

I'm surprised that Chevy let the big bodies come within 10 horsepower of a Corvette rating. So the three two barrels were worth 10 horsepower, huh? Just like the L78 396/425 Corvette was 50 hp stronger than the 66-up A bodies "because of better exhaust manifolds".

Unless they were installing Stahl headers on the Corvette line, I ain't buying it.

Which brings to mind my candidate for most underrated: L88 427/430. Even with Tonawanda's inconsistent build quality, that had to be 100 hp low.

12-14-2011, 10:50 AM	#1
Dan Bennett Member Join Date: Jun 2007 Posts: 355 Likes: 562 Liked 353 Times in 78 Posts	To Tell the Truth Yes, it was a game show in the 60s but it also could be applied to the horsepower ratings the manufacturers listed for their performance cars. There's a lot of controversy today with obviously incorrect ratings but it's really nothing new. How about your opinion on the engines of the musclecar era? Just to pass the time in the offseason here's mine, off the top of my head without a whole lot of research, and in no particular order. 71-up smog engines don't count. I'm sorting them according to their as-produced, showroom condition. I may have some of the HP numbers incorrect as I'm working from memory. "We'd rather have a big number for our ads" Ford 390/335 AMC 343/280(? not sure about the HP) Mopar 426/365 wedge Chevrolet 350/300 Ford 351 Windsor 4V Ford Boss 429 "That's the number we saw on the dyno (but at 4000 rpm), wink, wink" Boss 302/290 Z28 302/290 396/375 454/450 Cobra Jet 428/335 Stage 1 455/370 Ram Air IV 455/370 Olds 455/370 W30 Mopar 340/275 327/275 440/390 Six Pack 426/425 Hemi "We screwed up and put the right number on" Mopar 440/375 396/325 Additions are welcome. What is the engine that had the most bogus factory rating, high or low? I suppose you could check the NHRA factors for that era but I don't have them available.

12-14-2011, 05:22 PM	#4
Dan Bennett Member Join Date: Jun 2007 Posts: 355 Likes: 562 Liked 353 Times in 78 Posts	Re: To Tell the Truth Paul: Your reply got me thinking. If the 340 was refactored before it ever hit an NHRA event, how did that happen? I've heard stories of how sharp the Farmer was but I doubt he'd set a factor just by reading a magazine article or two. Did he look at the specs and come pretty close to the real HP? Big difference between now and then! Moose: I'm with you on the 440 Six Pack. The ones around here were pretty quick indeed. But I'm thinking it worked the other way with the 340 Six Pack. I don't think that engine, as produced, needed anywhere near that much carb - and that was just about the only real modification they made. Especially since they were only in the heavier E body, I'd bet they didn't want anything to do with a 340 Dart or Duster. We had a pretty active street scene around here even though it was a small town. Two friends used to duke it out numerous times a week. Eddie had a 66 427/425 Corvette and Fred had a 66 Coronet Hemi 4 spd. Both were pretty capable with a wrench. It was fun to watch since neither car could claim bragging rights. One car would win 3 out of 4 on the street but the other would win 3 out of 4 at the strip. I honestly can't remember which was which other than I'd bet the Corvette had the street advantage since the independent rear would squat and probably hook better on an unprepared surface. Even though I can't remember either car winning by more than a fender, this was long before redlights and who knows about a street start. They sure were a joy to watch.

12-14-2011, 06:09 PM	#5
Paul Ceasrine VIP Member Join Date: Apr 2009 Posts: 2,546 Likes: 0 Liked 10 Times in 10 Posts	Re: To Tell the Truth Dan, 340/275 HP, horsepower re-factor to 310 HP. Not sure on how the NHRA knew, but they did. Chrysler Performance was informed of the rating back in December 1967. Thats when the Southern California Dodge Dealers started building the E/S Dart GTS that Bill Shrewsberry raced. The #3150 lb. 68' 340 Dart GTS and 340 Barracuda's still were successful in E/S and E/SA, running 12.80's. Imagine them running in G/S in 1968,,,,,,,

12-14-2011, 06:46 PM	#6
Chris Barnes Member Join Date: Nov 2010 Posts: 139 Likes: 0 Liked 0 Times in 0 Posts	Re: To Tell the Truth I know we're supposed to be talking about racing here but I just have to say that the Mopar Six Pack option is one of the things that make America great. It is just the most stupid good fun ever put in a street car. Anyone who's ever driven one on the street knows what I'm talking about--those outboards are vacuum activated insanity!!! I'm too young and weak to have driven one with drum brakes but even still whoooooo!!!! Chris Barnes Wagons of Steel Stock 6621

12-14-2011, 08:27 PM	#9
Paul Ceasrine VIP Member Join Date: Apr 2009 Posts: 2,546 Likes: 0 Liked 10 Times in 10 Posts	Re: To Tell the Truth To Tell The Truth, The whole batch of 'B and' RB' engines had over-rated Horsepower figures from the factory. The 383 (330 and 325 HP engines) were much closer to 275 Horsepower. The 383 (335 HP Road Runner and Super Bee engines) were much closer to 290 Horsepower. Of course the 68' 440 cylinder heads, camshaft, valve springs and exhaust manifolds were worth an additional 15 HP. The 426/365 HP 'Street Wedge', closer to 300 HP. The 440/375 HP, still high,,,,,,,more in-line with 360 HP.

12-14-2011, 03:55 PM	#2
Hemi Moose VIP Member Join Date: Jan 2010 Posts: 2,824 Likes: 0 Liked 10 Times in 10 Posts	Re: To Tell the Truth If you remember all of that just by going by your memory, well then...as for any bogus engine horse power figures, I've always wondered what the true HP figure was for a 440 six pack motor, because it could give the 426 Hemi motor a run for their money.

12-14-2011, 04:25 PM	#3
Paul Ceasrine VIP Member Join Date: Apr 2009 Posts: 2,546 Likes: 0 Liked 10 Times in 10 Posts	Re: To Tell the Truth Dan, A couple right off the bat,,, The 1968 Ford Cobra-Jet 428/335 HP NHRA re-factored it to 360 HP immediately, which sounds about right on.. The 1968 340/275 HP, if the Horsepower remained at what the factory stated, the 1968 Barracuda or Dart GTS would have been classed in G/Stock instead of E/Stock in 1968. The NHRA re-factored the 340 to 310 HP even before the 1968 Winternationals. Again a fair HP rating. 1964/1965 Mopar 426/365 HP 'S' Street-Wedge. Completely over-rated Horsepower, 10.0 - 1 Compression Ratio Mild hydraulic camshaft,,,.(431/.431 Lift, w/268* duration) Standard cylinder heads (#2406516 castings) (2.08" intake / 1.60" exhaust) (Small-port exhaust) These cylinder heads were the same found on the 361/265 HP 2-Barrel engines Weak valve springs Horrible flowing cast iron intake manifold Carter AFB rated at 575 CFM Horsepower for the 426/365 HP 'S' Street-Wedge, rating probaby closer to 300 to 310 HP. Scary fact; In 1964 and 1965, the 64' Plymouth 426 'S' Belvedere and/or 'Sport Fury' ran in A/S or A/SA. In 1966, it was classed in B/S or B/SA, versus the 66' 427/425 HP Biscaynes and 66' Galaxie 500's 427/425 HP cars. In 1967, back into A/S or A/SA, versus the 67' Chevelle S396 396/375 HP cars. In 1968, C/S or C/SA, against the 68' 428 Cobra-Jet Mustangs. Talk about a 'tough challenge', they didn't stand a chance. Last edited by Paul Ceasrine; 12-14-2011 at 07:00 PM.