I am just about finished with the 521 DragWeek motor for my 66 Galaxie and I am undecided on what pressure plate to use. I have bought a 3200lb Mcleod diaphragm style unit but I am concerned it will still take two men and a boy to push the clutch pedal in. I had a 2300lb diaphragm type behind my 460 that worked just fine but I never ran it at the track. Is 3200lb overkill or do I need something like that to handle all that torque coupled with a 4400lb car? The transmission is a TKO600 5 spd.
Clamp pressure will depend on type of disc as well HP, weight,rear gear, 1st gear ratio and driving style.
3200 is a lot of pressure , but if your running a organic disc you may need that much with you combination.
If it is a truly street strip car you will have to compromise.
If you want something with a lightened pedal pressure you can go with a six paddle sintered bronze disc, it has a high coefficient and will hold with a lot less pressure than a organic disc, like around 1400# plate load,BUT is very aggressive and will chatter , but it will hold with slicks, HP and weight.
Next up would be the Sintered Iron single disc with a Long style PP that is adjustable both in Clamp(static) pressure and centrifugal counter weight. In a race application you can get down to 500# along with 10 -12 grams of counter weight and it will hold 600HP or more at 4000#(car weight) as long as its geared right.
You need some slip either from the clutch or tires with that TKO in order to keep from breaking it. IMHO............
5.89@115 New best, 1.31 60', 12-5-15 All Muscle and No Steroids!
69fb mustang ,509,Liberty Equalizer,5.29 ,31x10.5 w ,3309 w/driver.
I get to feel the torque of a BBF 4 times an 1/8 and 5 times a 1/4.