Max power with a Mustang clutch.

I wonder if any of you guys Stateside can advise on the maximum torque/hp that can be put through a standard Mustang clutch.

My GTD40 has a bell-housing large enough to take the standard flywheel, clutch plate and cover and I have only a 1966 289 with no mods except for a 600CFM Edelbrock carb and 1.75 exhaust headers therefore currently low power and o problems to date!

I wanted to know how far I can tune the engine before the clutch would slip. I'd rather not have to re-balance the bottom end, just put on some decent heads, inlet manifold and cam.

If I have this right from my notes, the clutch driven plate is a F4ZR-7550DA and the clutch cover a F3ZR-7563BA if this means anything to anyone.

Help gratefully received.

Regards
David C

David,
Not sure of the part numbers or how good they are, but I have a 157 tooth flywheel on a 351C, standard 10" diameter clutch disk and diaphram pressure plate (both McLeod), and they handled 410 ft-lb on the dyno OK.

IF you drive it on the street and don't drag race it a standard ford V8 chutch will take 300-325HP for a long time. Your renault unit would be OK up to about 300HP if you take it easy on it. Now all that being said. Tire grip, final drive ratio, 1st gear ratio, age of your clutch parts will all impact the question. If the parts you have are in good shape why not use them and get on with your build. You can always upgrade later. Ill get back to you with a centerforce upgrade that should be good for 400Hp using your parts. You did'nt say what kind of gearbox you have. If it is a renault then I can recomend a pretty good upgrade done by centerforce here in the USA. If you are using something else that takes a standard ford V8 flywheel then there is pretty much no limmit to what you can do. I still think that you should put it all together and get it running before upgrading a lot. The more changes you put into the car before you have the basic systems working just makes the whole thing more difficult later on. Been there done that.

[ February 10, 2003: Message edited by: Howard Jones ]

[ February 10, 2003: Message edited by: Howard Jones ]

Thx,

I didn't make it clear that I have had the setup running for over a year (~3000 miles so far). I pre-empted your advice and commissioned the car with a basic engine spec.

I have a Renault 21 turbo gearbox mated through the previously mentioned clutch (which are Ford parts) and use a Mcleod billet 157 teeth flywheel.

I was hoping to raise the bhp to around 350 which will probably be marginal with this setup?

David C

I believe I have the same clutch,and gearbox. Just go to the Centerforce website and begin with calling them in Arizona USA. Tell them the story about what you have and mention the GT40 Made by GTD with the renaut gearbox. They know about this setup and will rebuild your pressure plate and friction disk with their parts. This will increase clamping force buy about 90%. This is well within the requirements for 350HP. I think I remember that the cost was about 300.00 USD. Your shipping cost would be more than mine, I'm in California USA but this is still a pretty good deal. I have been told that several people in the US have used this setup for their 40,s

[ February 12, 2003: Message edited by: Howard Jones ]

Rather than ship parts from the UK to the USA, I think you'll find it cheaper to simply
buy new parts with higher holding force.
There are lots of Ford and Aftermarket choices. I think I paid $ 200 US for
both pressure plate and disc for mine.

Don't forget that Ford limited the torque
capacity of the standard parts to "save"
the transmission from overtorque.
A stronger clutch will shock the trans
and other driveline parts harder.

MikeD

Thanks guys, your advice is that I do need an upgrade to handle 350 bhp. Certainly $300 plus two lots of shipping sounds expensive, I know I can get a Mcleod street/strip clutch plate and cover for about 250 UK sterling and only 20 miles from home.

David

I was thinking you can do the mods you want, cam, heads, intake & carb, with the motor in the car. Leave the clutch alone and try it out. If it slips then fix it.

I have about 320/330 HP running to a Renault Turbo clutch and pressure plate. It is a stock unit and has performed well for over 10,000 miles. It can be made to slip but this has never been a problem - including a good number of runs at Willow Springs. However I agree with Howard. The units that Center Force rework are excellent and I have recommended them to everyone I know who is building 40 with from 300 t0 400 HP. The advantage seems to be in the drivability of the car. Some of the good high HP holding units seem to be very touchy for trailer loading and general street use where you might have to do a little creeping in traffic.