i went to buy the clutch parts for my project yesterday and asked for an 11" clutch assy and the guy asked me a couple questions about my application and then came out with 2 different assemblies. first one was a standard 11" clutch assy and the other was a 12" assy. the larger assy bolts to the same holes as the 11" on my flywheel and will obviously give me more grip. i didnt know if any of you guys were aware of this option so i thought i'd post it here.
I tried one once, that I'd scrounged from a truck. I seem to remember the pressure plate hitting the bell-housing. At least check it before you go through the work of putting it all together.
Adam thanks for the heads up, i didnt even think of that. I have an old 11" setup that i can do some comparing with.
Also remember the bigger the disc, the more rotating mass, and more load on the synchros when you shift. I speculate that when shifting fast, a big or dual disc increased the likelihood of missed shifts, though I have no idea how critical it really is. :idea2: You might ask the pure-stock/FAST guys what sort of disc is their favorite. If they can run 10's they must have found a bullet-proof clutch design that shifts well! Off-topic, but did you ever have a hd 3-speed in any of your cars? Mine shifted sooo much nicer than either of the 2 muncies I had. Luck, or not I wondered. It was in a 350 car with 10.5 disc. I stick to automatics now o No:
Adam the only three speed car i have ever driven was a 70 ElCamino and it was a POS(the whole car) i have heard great things about the hd Muncie 3 speeds and hope they are all true for me as well. I dont really intend to race this car much and hope the additional weight of the clutch assy wont make it a pain to shift. i weighed my old 11" assy and it weighs 23 lbs 13 ounces, the 12" assy weighs 2 lbs more
I have run 11" clutches from LUK, HAYS and CenterForce in my 455 4 speed Pure Stock convertible. The LUK was ok for the street but didn't like the drag strip abuse. The Hays gold was a bit smoother for street driving lasting for 5 years, 250+ runs down the track and over 20,000 miles. The CenterForce has better clamping pressure at high rpm due to it's design, lasted longer than the Hays but was a bit jumpier on the street.
I still have the above-mentioned toploader and factory Hurst that came out of my 68 GS. I've been saving it for a special project like yours...
Adam my 3 speed is a muncie. it has a 1" counter shaft and a cast iron case I had the option of buying a toploader 3 speed out of a V8 Maverick but went for the muncie instead..i thought about buying a new Super T-10 but at 1400.00 that thought lasted about 3 seconds. since my gear ratios are identical to a th400 and i'm running a 3.42 rear gear i figure it should get up an go fairly well. first picture is the 3 speed that came in the car.. second picture is the Muncie MC-1 which was the base trans on 69 SS chevelles
I think you'll do good, and doubt the 4-speed will have much of a performance advantage behind a 455. I'm in the "how did this become such a money-pit" mode right now myself. Ya done good by saving that stupid amount of money by choosing the 3-speed in my opinion. With your shopping skills, that's the price on another GS!
