Main Menu
|
Nevada Classics
|
Advertise at CC
|
S |
M |
T |
W |
T |
F |
S |
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
24 |
25 |
26 |
27 |
28 |
29 |
30 |
|
|
|
|
|
CC Advertisers
|
|
2Likes
-
1
Post By hauss
-
1
Post By Tom Wells
03-13-2019, 04:31 AM
|
|
CC Member
|
|
|
Join Date: Jun 2004
Location: Jasper, GA,
GA
Cobra Make, Engine: Owned CSX 3121 1969-1975. Went to the dark side and bought a 'Vette. May yet repent and be saved.
Posts: 657
|
|
Not Ranked
Food for Thought
Having time to daydream, I wonder if any of the smart people (unlike this writer) who kept their original 427/428 Cobras into the chassis dyno era had them tested with the as delivered, under the car exhaust system. When installed in the big Fords, the 427 was equipped with heavy, but efficient looking cast iron exhaust manifolds. These were a no go in the Cobra engine compartment, so clunky 390 units took their place. On the high revving 427, this change had to have killed power over 5000 rpm. Recently, a friend with an ERA sporting a built 427/454 engine with a strong cam and side pipes ran his car on a Dynojet and could not hit 400 at the wheels, which led to my original question.
|
03-13-2019, 06:46 AM
|
|
CC Member
|
|
|
Join Date: Feb 2001
Location: BRADENTON,
FL
Cobra Make, Engine: KIRKHAM 427 S/C, SHELBY 427 ALUM. STROKER
Posts: 1,396
|
|
Not Ranked
probably restrictive sidepipes
__________________
"When Injustice becomes Law,
Rebellion becomes Duty." T. Jefferson
|
03-13-2019, 07:07 AM
|
|
CC Member
|
|
|
Join Date: Oct 2016
Location: Pleasanton,
CA
Cobra Make, Engine: ERA 824 with 470 FE BBM street 427
Posts: 550
|
|
Not Ranked
I hope to hit 300 at the wheels with my built 470 (455HP/500 ft-lbs flywheel dyno) due to the lack of hood scoop and restrictive under car exhaust. I figure it will be plenty for a 2300 lb car.
|
03-13-2019, 11:18 AM
|
|
CC Member
|
|
|
Join Date: Feb 2018
Location: Lodi,
CA
Cobra Make, Engine: 427 manowar forged crank roller rockers . BIG CAM.
Posts: 784
|
|
Not Ranked
Funny I never dynoed mine but, I can tell you 3rd gear, just step on throttle, no dumping of clutch and,the tires will go up in smoke. 315 17 nittos 600 hp I am told and I believe them!
|
03-13-2019, 12:25 PM
|
|
Senior Club Cobra Member
|
|
|
Join Date: Mar 2000
Location: St. Augustine,
FL
Cobra Make, Engine: E-M / Power Performance / 521 stroker / Holley HP EFI
Posts: 1,912
|
|
Not Ranked
__________________
Wells's law of engine size: If it matters what gear you're in, the engine's too small!
|
03-13-2019, 12:25 PM
|
|
CC Member
|
|
|
Join Date: Jan 2019
Location: Houston,
Tx
Cobra Make, Engine: UCC GT 427
Posts: 206
|
|
Not Ranked
Chassis dynos are notoriously inaccurate, the dynojets always read too high, the tuners will tell you the Mustang dyno is more realistic. Dyno jet is akin to running the car down hill while the Mustang puts more load on the car. Albeit the engine dyno still the gold standard.
|
03-13-2019, 09:14 PM
|
|
CC Member
|
|
|
Join Date: Feb 2018
Location: Lodi,
CA
Cobra Make, Engine: 427 manowar forged crank roller rockers . BIG CAM.
Posts: 784
|
|
Not Ranked
I was never given a chart I was only told by past owner. Car has a stroked man o war block huge cam 0 vac at idle and a 780 cfm quickfuel carb victor aluminum heads.3rd gear will boil the tires no kidding! I would say 600 hp but I never personally dynoed the car just comparing to other cars I have worked on.
|
03-14-2019, 04:07 AM
|
|
CC Member
|
|
|
Join Date: Feb 2009
Posts: 1,690
|
|
Not Ranked
I had mine on a dyno and it read 452 rwhp. If you factor in a 17% parasitic loss, that is about 544 crank hp which was just shy of where it was supposed to be.
The problem they had with my car was the tires. They were older tires and due to the light weight of the car and IRS, were slipping on the dyno. I think the dyno was a Mustang with 24" rollers. I have not put it back on since the good tires were installed.
Last edited by joyridin'; 03-14-2019 at 04:10 AM..
|
03-14-2019, 05:06 AM
|
|
CC Member
|
|
|
Join Date: Dec 2001
Location: Castalia,
Oh
Cobra Make, Engine: EM cobra, 450 inch sbc running a best ET of 9.14..so far..ALL MOTOR...approx 800 horse.............ERA with 482 FE..All Aluminum Engine
Posts: 1,395
|
|
Not Ranked
The last time on the dyno, with MT ET/Streets, hit 682 TQ @ 2700 rpm and spun the tires.
__________________
Jack
XSSIVE .....
|
03-14-2019, 09:57 AM
|
|
CC Member/Contributor
|
|
|
Join Date: Sep 2016
Location: (Beautiful) Sequim,
WA
Cobra Make, Engine: Pacific Roadster, 347 cu.in. 5-speed
Posts: 1,940
|
|
Not Ranked
I've posted this before. Mark Donohue once said " If it wouldn't spin the tires in top gear at top speed then it needs more Horsepower" Nuff said Cheers Tom.
|
03-15-2019, 06:44 PM
|
|
Senior Club Cobra Member
|
|
|
Join Date: May 2001
Location: Florence,
AL
Cobra Make, Engine: RCR GT 40 & 1966 Fairlane 390 5 speed
Posts: 4,511
|
|
Not Ranked
Keith Craft once told me that of the engines he dyno-ed and then installed into a Cobra, and then chassis dyno-ed he saw a 20% loss.
__________________
''Life's tough.....it's even tougher if you're stupid.'' ~ John Wayne
"Happiness Is A Belt-Fed Weapon"
life's goal should be; "to be smarter than inanimate objects"
|
03-15-2019, 07:22 PM
|
|
CC Member
|
|
|
Join Date: Feb 2018
Location: Lodi,
CA
Cobra Make, Engine: 427 manowar forged crank roller rockers . BIG CAM.
Posts: 784
|
|
Not Ranked
Personally If it runs crisp, no pinging no blubbering, then I would be happy. You could have 1000hp and, if it ran like crap, you would not be happy.That is what you should be looking for, not hp numbers .Now that"s food for thought.
|
03-15-2019, 07:24 PM
|
|
CC Member
|
|
|
Join Date: Feb 2018
Location: Lodi,
CA
Cobra Make, Engine: 427 manowar forged crank roller rockers . BIG CAM.
Posts: 784
|
|
Not Ranked
BUTT dyno
Quote:
Originally Posted by Tom Wells
|
35$ levi 505 comfort fit butt dyno
|
03-16-2019, 07:29 AM
|
|
Senior Club Cobra Member
|
|
|
Join Date: Mar 2000
Location: St. Augustine,
FL
Cobra Make, Engine: E-M / Power Performance / 521 stroker / Holley HP EFI
Posts: 1,912
|
|
Not Ranked
Lol!!
__________________
Wells's law of engine size: If it matters what gear you're in, the engine's too small!
|
03-16-2019, 08:19 PM
|
|
CC Member
|
|
|
Join Date: Feb 2018
Location: Lodi,
CA
Cobra Make, Engine: 427 manowar forged crank roller rockers . BIG CAM.
Posts: 784
|
|
Not Ranked
Quote:
Originally Posted by Tom Wells
Lol!!
|
Glad to see you get what I am saying you are one of the few.
|
03-17-2019, 04:37 AM
|
|
CC Member
|
|
|
Join Date: Apr 2009
Location: Little Rock area,
AR
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
Posts: 4,483
|
|
Not Ranked
Quote:
Originally Posted by Dwight
Keith Craft once told me that of the engines he dyno-ed and then installed into a Cobra, and then chassis dyno-ed he saw a 20% loss.
|
I think on his restoration motors like 428 CJs he probably ran the stock manifolds on the dyno. But on custom built engines KC used tuned headers on his dyno runs - at least going by my experience. So taking a 500 HP engine and installing it in a chassis with 390 log manifolds would probably kill the upper end and could possibly cost 25% at the rear wheels in theory dropping such a motor to below 400 HP.
The day they dyno tested my engine they had three 428 CJ restoration (stock) engines lined up outside the dyno room they had just finished breaking in and running. I asked the dyno operator what they typically made and he said usually stock they pulled about 410 HP. A 428 CJ is not very different from a Q-code 427/400 HP center oiler from the 63 - 64 era other than a bit less bore and bit more stroke and everyone knows by then the 428 CJ was grossly under-rated by Ford at 335 HP. So the 410 HP would seem to compare pretty closely to what Ford rated the 427/400 engine at - but both 427 Q and 428 CJ ran a more efficient exhaust manifold than the 390 log manifolds.
Detroit wasn't messing around with HP ratings too much until the later 60s and their engines in the restoration dyno reports I see in magazines like Car Craft and Muscle Car Review seem to run right on the old manufacturer ratings for the most part. Course that was stripped of accessories and the old rating system.
|
03-17-2019, 04:46 AM
|
|
CC Member
|
|
|
Join Date: Jun 2004
Location: Jasper, GA,
GA
Cobra Make, Engine: Owned CSX 3121 1969-1975. Went to the dark side and bought a 'Vette. May yet repent and be saved.
Posts: 657
|
|
Not Ranked
Closer to the answer i was seeking. The resurgence of the 427 vs. 428 debate really inspired my original post. Given the differences between the two, I suspect that those 390 manifolds hurt the shorter stroke/higher revving 427 more.
|
03-17-2019, 05:28 AM
|
|
CC Member
|
|
|
Join Date: Apr 2009
Location: Little Rock area,
AR
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
Posts: 4,483
|
|
Not Ranked
Quote:
Originally Posted by DanEC
A 428 CJ is not very different from a Q-code 427/400 HP center oiler from the 63 - 64 era other than a bit less bore and bit more stroke .
|
I guess I should have said also a bit less cam and compression. And I think KC's assembly care was probably a bit greater than standard FOMOCO at the time.
Quote:
Originally Posted by marcocsx3121
Closer to the answer i was seeking. The resurgence of the 427 vs. 428 debate really inspired my original post. Given the differences between the two, I suspect that those 390 manifolds hurt the shorter stroke/higher revving 427 more.
|
I would say so too. Using Chevy for a comparison may not be popular but the 427/390 L36 hydraulic motor was rated at 390 HP in the Corvette with streamlined manifolds but lost only 5 Hp when put in an Impala with log type 396 manifolds and Chevy very clearly said it was due to the exhaust. The higher revving 1965 396/425 Corvette with streamlined exhaust manifolds dropped to 396/375 when it was put in the Chevelle that year with a bit milder hydraulic cam (vs mech in Corvette) and standard 396 manifolds to fit the chassis. Even later year 396/375 motors with the L72 mechanical cam kept the 375 rating with the log manifolds in the 66 and later Chevelles, Camaros and Novas.
|
03-17-2019, 10:22 AM
|
|
CC Member
|
|
|
Join Date: Apr 2009
Location: Little Rock area,
AR
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
Posts: 4,483
|
|
Not Ranked
What would have been interesting was if someone back in the day had run quarter mile times between a 428 Street Car and a 427 Street Car to see what the difference was. Since the 390 manifolds probably hurt the upper end of the 427 more than the 428 there likely wasn't much difference between the two in a 2500 lb car with 7 inch wheels and standard tires back in use then.
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -7. The time now is 02:30 AM.
Links monetized by VigLink
|