To Tell the Truth

[Arnold Greene]

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]

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]

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.

[Paul Ceasrine]

Dan

The 1968 '340 GTS' Darts were rolling off the Los Angeles assembly line in August 1967.

So it was not suprising to see one running at one of the drag strips in
D/S or D/SA in 1967, before the NHRA re-factored them to 310 HP
for 1968, and re-set the stock classes.

Same thing with the 383 Road Runner and Super Bee,
as they started showing up in late-October 1967.
They fell into the 1967 class of B/S or B/SA.
1968 found them in E/S or E/SA, same class as the 340 GTS Darts and
340 Barracuda's.

pc

[HEMIDARTDAVE]

A few years ago I remember seeing a graph of the actual in-house Chrysler HP numbers for the 440 6 packs in '69. The 390 HP rating was taken at a mid-high rpm, and I think it topped out @ 440-450 HP at the peak HP/RPM range, I seem to remember a 444 HP run. I'll see if I can find it and post it.

[Alex Denysenko]

My picks not counting those that are already posted.

Over rated.

Nash 66 to 69 290-225 more like 200

Buick 67 GS 340-260 more like 220

Chevy 58 to 60 348-280 more like 250
Chevy 63 to 65 409-340 more like 300
Chevy 63 to 65 327-365 more like 320
Chevy 67 to 69 427-400 more like 370

Mopar 65 to 67 273-235 Commando more like 200

Ford 63.5 to 67 289-271 more like 240
Ford 65 to 67 289-225 more like 200
Ford 66 to 67 390-325 more like 300 (the real ones without NHRA aluminum PI intake and CJ carb)
Ford 69 351W-290 more like 250

Oldsmobile 64 to 67 330-310 more like 250

Pontiac 67 326 HO 280 more like 250
Pontiac 67 to 69 428 pick one, they were all dogs when new

Underated

Most have been already mentioned so far except for these few

Nash 69 SS 390-340 more like 425

Ford 66 Shelby GT-350S 289-390 more like 430 (the original 1000 foot dump during road magazine road test 14.00 @ 92 MPH)

Pontiac 400 RA in any Firebird at least 25 shy

[Paul Ceasrine]

Alex,

I like the way you think,,,,,,,,

That 1967 Pontiac Firebird 400/340 HP Ram Air,,,,,
an easy 360 horsepower.

The 69' Pontiac GTO 400/370 HP Ram Air IV,,,,,,
they were kiling everyone one in D/S and/or D/SA in 1969.

That #3500 lb. GTO should have been re-factored to 390 Horsepower, and
classed in C/S and/or C/SA.

[k.pascoe]

Ok my turn.

Ford
69-71 429ci-360 hp more like 300hp
69-71 460ci-365 hp more like 320hp (gobs of torque though)
Any year any version 390ci hp overrated!! The '66 352 ran better!

A past editor at Car and Driver worked as an powerplant engineer for Mopar or GM (not sure) wrote a couple times none of the engines back then made close to the power after installed in the car. They would super tune the engines on the dyno; open headers, no power acc. drag. He said they would loose up 50 to 75 horse after installed in the car.

[Paul Ceasrine]

I wouldn't comletely discount the 1966 390/335 HP engine.

They did a pretty good job in 1966, classed in C/S and/or C/SA.
Especially the 'factory/dealership' backed Mercury Comet Cyclone GT's.

The 'Factory/Dealership' backed C/S cars, were running 13.00's..

And some of the 'Top' C/SA cars could run 13.20's.

Currently the 335 HP seems out-of-line, but back in the day they were 'runners'.
They could compete in C/S and C/SA classes, but were just a notch below the
GTO's and 4-4-2's.