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Old 3rd June 2018, 12:44 PM   #1
f250r
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power

Can these cars handle 600=hp? Trans, half axles, frame? I have a 2005 CAV. Looking at 13" wide rear tires. What can break if not equipped correctly?
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Old 3rd June 2018, 01:05 PM   #2
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Re: power

Are you going to race the car??? I have 470 hp in my cav and it is more than enough. E mail the factory, they will know how much power the car can handle. For sure you will break the weakest link
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Old 3rd June 2018, 05:11 PM   #3
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Re: power

I have 550 in my 2100lb cobra and I want the gt40 to feel them same or faster. It will be a street car but tractable also. I am going with a mendeola transaxle and I want to get some nice half shafts, then I see no weak links.
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Old 4th June 2018, 07:44 PM   #4
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Re: power

Put some sticky tires on it and Hoon it you'll find the weak link. 450-500hp in a well balanced midengined car will feel and be faster than a cobra that can't get it to the ground with much over 400hp.
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Old 4th June 2018, 08:07 PM   #5
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Re: power

Nah, put some BFG TA's on it and it will never break! Of course it will never hook up but......

So long as you can break the tires loose, you will not hurt the drivetrain.
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Old 4th June 2018, 08:46 PM   #6
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Re: power

Rick! that's funny!!!!!! The cool thing about BFG TA's is you can make your own oil. It comes out of the tires in about a lap and a half....

Put a $5000 400HP 351 in it and spend the rest on tires.....That's my story and I'm sticking to it.
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Old 4th June 2018, 09:06 PM   #7
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Re: power

Quote:
Originally Posted by Howard Jones View Post
Rick! that's funny!!!!!! The cool thing about BFG TA's is you can make your own oil. It comes out of the tires in about a lap and a half....

Put a $5000 400HP 351 in it and spend the rest on tires.....That's my story and I'm sticking to it.
Howard,

You are closer to the truth than many want to admit! Big power is nothing without big traction. I still am amused by those who spend tens of thousands to make horsepower but won't spend hundreds to be able to use it!

Dyno racers we call them, comparing HP on the dyno but never being able to actually use it!
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Old 4th June 2018, 10:37 PM   #8
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Re: power

I am getting Avons. Found a 12.5in wide rear with 15In bulge. Should fit my gulf rear and should still break traction but I am also getting a beefy trans and half axle setup. I am going overkill so I don't get killed.
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Old 5th June 2018, 08:27 AM   #9
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Re: power

Nick,

i know some one who has avons with less than 500 hp and they broke loose at 100 mph.

600hp with out traction control = tire smoke.

Just my 2 cents
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Old 5th June 2018, 12:53 PM   #10
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Re: power

The Avons I'm familiar with (and have on my car) are treaded race tires, which stick very well when fresh, but traction degrades fairly rapidly with time as well as miles. So some Avons stick better than others, depending on their age and mileage.
Fresh Avons on 14" wide rear wheels handle the 630hp I have pretty well, but you are always going to have some slip in lower gears when you are really on it. (I have a solid roller 440" SBF in a 2400# SPF Mk1).


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Old 5th June 2018, 01:05 PM   #11
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Re: power

Nick, I was wondering what the rest of the power train was you were going to use? Gearbox, clutch, driveshafts, etc. My guess is you will be deep into $20K in power train with +600HP.
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Old 5th June 2018, 01:25 PM   #12
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Re: power

going with mendeola trans, .6 5th ger, axle haven't decided yet, cluth haven't decided yet and probably will be 20k range once done but will be hard to destroy. Either way I know you can smoke any tire depending on driving style. I have GY billboards on my cobra with 550hp in a 2,000lb car and love the tires. Avons look to be the same. I know they will be light and darty, grab street ruts but I am use to a very responsive tire with the GY. I just want to make sure it has similar feel to the cobra on a launch. Good thing the motor and trans sits close to the axles on a GT40 so nice weight over the tires. I will post result and pics one I am done with the work.
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Old 5th June 2018, 01:27 PM   #13
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Re: power

Quote:
Originally Posted by jd3 View Post
The Avons I'm familiar with (and have on my car) are treaded race tires, which stick very well when fresh, but traction degrades fairly rapidly with time as well as miles. So some Avons stick better than others, depending on their age and mileage.
Fresh Avons on 14" wide rear wheels handle the 630hp I have pretty well, but you are always going to have some slip in lower gears when you are really on it. (I have a solid roller 440" SBF in a 2400# SPF Mk1).


Jack
Jack,


Can you tell me what size tires, model, and rim size you went with?
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Old 5th June 2018, 02:22 PM   #14
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Re: power

Quote:
Originally Posted by f250r View Post
going with mendeola trans, .6 5th ger, axle haven't decided yet, cluth haven't decided yet and probably will be 20k range once done but will be hard to destroy. Either way I know you can smoke any tire depending on driving style. I have GY billboards on my cobra with 550hp in a 2,000lb car and love the tires. Avons look to be the same. I know they will be light and darty, grab street ruts but I am use to a very responsive tire with the GY. I just want to make sure it has similar feel to the cobra on a launch. Good thing the motor and trans sits close to the axles on a GT40 so nice weight over the tires. I will post result and pics one I am done with the work.
Will the transmission fit under the bodywork?
I have read they are too long and hang out the back.

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Old 5th June 2018, 06:55 PM   #15
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Re: power

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Originally Posted by f250r View Post
Jack,


Can you tell me what size tires, model, and rim size you went with?


My Avons are 12.5/27.0-15, and the tread width is actually a little more than 13.5" wide. They are on 15" BRM style wheels, by Vintage Wheels, iirc. The wheels are actually 13" wide, lip to lip (I measured them).


BTW, I also have a set of 17" BRM wheels, same size, that have Michelin Pilot Sport 335/35 ZR17 tires. These actually grip surprisingly well, and they don't throw as many rocks up into the wheelwells. And they have a DOT stamp on them for nosy policemen. I actually run these most of the time.


FYI, I run a RBT transaxle, built with GT40 gearing (see Configurator).
2.58/1.61/1.14/.846/.642 with 3.78 R&P. This is just about perfect gearing for my car. The engine is a 440" Windsor stroker with CHI heads, built for street with lots of cylinder pressure (200psi cranking), and emphasizing low and mid range power.


Jack

Last edited by jd3; 5th June 2018 at 07:05 PM. Reason: Added RBT configurator address
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Old 5th June 2018, 08:05 PM   #16
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Re: power

Thank you for the info, and yes the mendeola will slightly stick out.
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Old 5th June 2018, 08:37 PM   #17
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Re: power

Quote:
Originally Posted by jd3 View Post
My Avons are 12.5/27.0-15, and the tread width is actually a little more than 13.5" wide. They are on 15" BRM style wheels, by Vintage Wheels, iirc. The wheels are actually 13" wide, lip to lip (I measured them).


BTW, I also have a set of 17" BRM wheels, same size, that have Michelin Pilot Sport 335/35 ZR17 tires. These actually grip surprisingly well, and they don't throw as many rocks up into the wheelwells. And they have a DOT stamp on them for nosy policemen. I actually run these most of the time.


FYI, I run a RBT transaxle, built with GT40 gearing (see Configurator).
2.58/1.61/1.14/.846/.642 with 3.78 R&P. This is just about perfect gearing for my car. The engine is a 440" Windsor stroker with CHI heads, built for street with lots of cylinder pressure (200psi cranking), and emphasizing low and mid range power.


Jack

Jack, did you have to have your tires grooved?
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Old 5th June 2018, 10:13 PM   #18
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Re: power

Quote:
Originally Posted by f250r View Post
Jack, did you have to have your tires grooved?


No, they were treaded from the factory. "Historic all weather pattern tires" (the section width is 15.25" in case you were wondering). This info is off the Avon site here:


15" Historic all weather | Avon Motorsport


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Old 5th June 2018, 10:48 PM   #19
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Re: power

What size tire you running on the front with the Avons? Can you send me a pic of the rear. You have the gulf wide year I am sure?
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Old 6th June 2018, 07:59 PM   #20
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Re: power

Quote:
Originally Posted by f250r View Post
What size tire you running on the front with the Avons? Can you send me a pic of the rear. You have the gulf wide year I am sure?

I just had the 15" Avons dismounted yesterday, and I measured the front BRM wheels as 9" wide, lip to lip. The front Avons are 9.1/23.5-15, the same historic all weather tires as the rear, with same tread pattern. It is the exact same pattern as shown in the Avon historic all weather tire page you can click on in my comment #18 in this thread. And yes, the bodywork is the extra wide type from SPF.


Jack
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