Horsepower of original 427
 

Would like to know the h.p. Of the early 427s? I assume it varied but what models and years had what h.p.

Believe the 427 was rated at 425hp 480 torque.
Just from memory though.
The 428 Cobra was 355hp.

427 Cammer was rated at 616hp.

Those were very optimistic figures. Remembering that both the 427 and 428 "street" cars were saddled with very restrictive, big block Galaxie exhaust manifolds, I'd bet RWHP numbers would struggle to break 300.

For comparison
 

I am interested in these numbers given today's h.p. Numbers. My engine is 460h.p. And I am guessing with current updated suspensions would be competitive.

Ford Times August 1965: 427 CID 425 HP (street tune)
Car and Driver November 1965: 427 CID, 485 HP @ 6500 RPM, 480 lbs-ft @ 3500 RPM
Car and Driver April 1981: 427 CID, 475 HP @ 6500 RPM
Car and Driver April 1981: 428 CID, 355 HP

I'm not 100% sure of the C&D figures from November 1985, the scanned copy I have is hard to read.

More telling than raw HP and torque numbers, here's some published data on lbs/HP:

260 Cobras:
Sports Car Graphic May 1962: 1890 lbs, 260 HP, 7.3 lbs/HP
Road & Track September 1962: 2020 lbs, 260 HP, 7.8 lbs/HP
Car and Driver May 1963: 2120 lbs (full tank), 260 HP, 8.2 lbs/HP

289 Cobras:
The Motor October 1967: 2100 lbs, 271 HP, 7.7 lbs/HP

427 Cobras:
Ford Times August 1965: 2150 lbs, 425 HP (street tune), 5.1 lbs/HP
Car and Driver November 1965: 2529 lbs, 485 HP, 5.2 lbs/HP
Car and Driver April 1981: 2630 lbs, 475 HP, 5.5 lbs/HP

There are some real anomalies here, particularly when it comes to weight. I expect the Ford Times data is a dry weight, while the C&D figures are closer to 'as tested' weights.

I posted this in another thread.

Way back 20 plus years ago I witnessed a dyno run of a NOS 427 that came out of a crate,
it was suppose to be a 425HP version that was "under rated" no matter what carb or how much timing they put into it, the best they saw was 410 HP, so I really don't believe cobras had as much HP as we would like to believe they had, I figure it is just like anything else over the years the numbers just get bigger and bigger, every time the story is told.

Dean

When the 427 returned to the street roadster after the 428 models, it was the 410 HP single 4bbl version (probably with the log style exhausts manifolds again).

Here is one take: Replica vs. Real | Articles |

Not taking into account the type of vehicle, or the type of exhaust manifolds.

The stated HP figures that are well known and written in Ford manuals and car brouchures (sp) are as follows.

The 427 with 2 x 4 carbs was advertised at 425 HP
The 427 with a single 4 was advertised at 410 HP

The 1968 W Code 427 in the Cougar GT-E was advertised at 390 HP. So is that because of the insurance worries, going from 410 to under 400??
Kind of goes along with the 428 CJ at 335HP


The SOHC 427 with a single 4 was 617 HP
The SOHC 427 with 2 x 4 was rated at 677 I believe

If you ordered a 427 2 X 4 engine at the parts counter, it was advertised at 485 HP.

Since Shelby and Ford didn't car about insurance companies and HP ratings for the Cobra race model, it was rated at the 485

Some years back a person who purchased and still owned an original sent me some PDFs of scanned original Shelby specs. I will past from the PDFs.

This is the 427 Competition Cobra:
Water cooled V-8, with cast iron block, magnesium
intake manifold, alloy cylinder heads,
lightweighvt alvesa nd alloyw ater pump.
Bore & stroke . .4.24 x 3.7B in
Displacement 427 cu in
C o m p r e s s i o n r a t i o . . . 1 2 . 4 : 1
Horsepower. . . . . . . 4 8 0 @ 6500 rpm
Torque 510 ft-lbs @ 3700 rpm
Carburetion .4 V Holley

This is the 427 Street Cobra:
Water-cooleVd -8,w ith cast iron block,5 main
bea ri ngs
Bore & stroke . .4.24 x 3.78 in, 107 x 96 mm
Displacement . . . . .427 cu in, 6998 cc
Compressiorna t i o . . . . . . . 1 0 . 4 t o o n e
Carburetion . .Two 4-bbl Holley
Valveg ear Pushrod-OHV
Horsepower (SAE) . . .425 bhp @ 6000 rpm
Torque . . 480ft-lbs@ 3700 rpm

This is the 428 StreetCobra:
428 CID Speclal Police Interceptor Ing'inc r'riih rnod'fii caticns
by Shel by Ameri can.
l^lat,er cooled, crst il"oir block witit 5 ma'in bear-ings
Sore 4.13 Siroke 3.9t] Dispjacetnent q28 cubic irrches-70l4cc
Compression ratio 10.0:l Carburet'ion 1-4V Ford
Horsepower 390 @ 5000 RPM Torque 475 f t 1bs. @ 3700 RPM

The cammer never went into any production cars nor Cobras. Shelby was known to be less than totally honest, so read this with a grain of salt. Also remember that in the 1960's Hp was flywheel on a dyno with no belts attached and air cleaners and exhaust did not need to resemble what would be in the car. In the early 1970's, the government said they had to be dynoed as installed in the car (all belts, air cleaner, and exhaust). If you look at the specs you will see all manufactures seemed to loose about 100 Hp that year. Keep that in mind when you compare to today's numbers.

In the mid 1990's the formulas for correcting the Hp for standard sea level atmospheric conditions had likely be revised several times since the 1960's. Remember in the 1960's engineers were still using slide rules and computers were more of a pipe dream. It took a long time to get it right, and some will tell you it still isn't exact.

Same engineers who used slide rules put a man on the moon and develop the SR71 which still hold most records for fastest airplane. Fast forward 50 years and they can't use all of todays computers to work out the bugs on the F35 to save their lives.

If the muscle cars of the 60's & 70's had the tire technology we have today there would be much much lower #'s for 0-60 and 1/4 mile times in the record books

Hot Rod did a comparison of 60's small blocks in the Jan 2010 issue. They configured the engines as closely as possible to the originals, and ran them on a modern dyno with dyno headers and the same holley carburetor. They did not test a 427FE, but the numbers are interesting.

Shelby 289 - rated 306HP, tested 302HP
L76 327 - rated 365HP, tested 356HP
Boss 302 - rated 290HP, tested 372HP
69 DZ302 - rated 290HP, tested 356HP
70 LT1 (350) - rated 370HP, tested 353HP
70 351C Cobra Jet - rated 300HP, tested 365HP
71 LT1 (350) - rated 330HP, tested 359HP
71 Boss 351 - rated 330HP, tested 383HP

I had a 64 Galaxie 500-XL with the dual four 427 and it was rated at the 425 horse given above, but the small tires they came with made it impossible to really get on it until you were above 60 MPH. But I don't believe it had as much power as they claimed. My 69 NASCAR Cobra with the 428 Cobra engine which was rated at 335 horse I had dynoed and it came out at 440 horse using the original exhaust manifolds which were the same as the 64 427 had as it has 427 heads and the bottom end is LeMans rods and stuff.

Ron

Nice teaser, and without aksing for trouble: I would not compare the SR-71 Skunk Works engineers to automotove engineers.. ;-)

It's torque that accelerates a car, which makes a 427 very quick!

When I picked up my motor from Keith Craft's shop he had a couple 428 CJ restoration (stock) motors sitting near the dyno room after testing. I asked the dyno operator what they ran and he quoted getting around 430 to 440 HP I believe from memory.

I've done a couple of "period correct" engines, both street and race.

I built a 428CJ for a guy in Mississippi. It had the correct CJ heads, we just did a good valve job and put some Ferrea valves in them. Used a 227/233 @ .050" hydraulic roller cam, about .600" lift. Intake was the 75 lb cast iron CJ piece with no porting whatsoever. Compression was 9.7:1. It made 422 hp and around 460 lb-ft if I remember correctly.

Also did a 427 LR 2x4 for an FIA road race Galaxie. It was a rules engine, but we used the factory heads (did some heavy work on them), the factory 2x4 LR intake, and a solid flat tappet camshaft. It was an 11:1 engine. It made 510 hp @ 6000 through 6500 and 511 lb-ft of torque. That particular engine had a $ crank, with the rod journals turned to 2.200", Oliver 6.800" rods, and RaceTec pistons running .043/.043/3mm ring sizes.

And if all these contradictory posts do not confuse...what does?