Which Clutch Kit for a 383??
12-16-2011, 02:09 AM
#1
Instructor
Thread Starter
Which Clutch Kit for a 383??
Greetings fellow C3'ers,
Over the Christmas break I shall be replacing the existing 350 in my '70 'vette with a 383 rated at 440hp.
Question: I will be using an 18lb flywheel, so which clutch kit will serve me the best? I've seen a multitude at Summit but first hand experience from you guys will help guide me along.
Size and style to handle the horses???
Thanks,
B
Over the Christmas break I shall be replacing the existing 350 in my '70 'vette with a 383 rated at 440hp.
Question: I will be using an 18lb flywheel, so which clutch kit will serve me the best? I've seen a multitude at Summit but first hand experience from you guys will help guide me along.
Size and style to handle the horses???
Thanks,
B
12-16-2011, 05:54 PM
#2
Melting Slicks
I like the CenterForce DF (dual friction). Has 90% more holding power than stock (according to CenterForce) and the clutch pedal is as easy on your leg as a new Toyota.
I'd go with the 11" set up which means you need a 168 tooth flywheel (14") and the larger bellhousing and "offset" starter (has offset mounting bolts).
I'd go with the 11" set up which means you need a 168 tooth flywheel (14") and the larger bellhousing and "offset" starter (has offset mounting bolts).
Last edited by 73, Dark Blue 454; 12-16-2011 at 06:04 PM.
12-16-2011, 10:46 PM
#3
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St. Jude Donor '05
Centerforce DF here also so far love it. 
12-17-2011, 12:40 AM
#4
Burning Brakes
What do you guys think of the Ram (Musclecar, Powergrip, Force 9.5) or Zoom (30000 Series or High Performance) Clutches that Summit has to offer?
12-17-2011, 08:09 AM
#5
Instructor
Thread Starter
Followup question...
How do I determine (prior to dismantling) flywheel tooth size and clutch disk size ie 10.4 or 11" - 10 spline or greater??? I'd like to order parts beforehand but not sure if this can be determined at this point in time...
How do I determine (prior to dismantling) flywheel tooth size and clutch disk size ie 10.4 or 11" - 10 spline or greater??? I'd like to order parts beforehand but not sure if this can be determined at this point in time...
12-17-2011, 09:23 AM
#6
Team Owner
What kind of transmission do you have? I use a Protorque 3.1 hp mini starter. I use the 168 tooth. Your 350 came with a 153 tooth. So if you want to keep your starter you need the 153.
As for fly wheel weight. If you have a heavy crank and damper you can use a 15# fly wheel.
Most moder hi performance clutches are easy on the leg pressure.
http://www.summitracing.com/search/B...?Ns=Rank%7cAsc
As for fly wheel weight. If you have a heavy crank and damper you can use a 15# fly wheel.
Most moder hi performance clutches are easy on the leg pressure.
http://www.summitracing.com/search/B...?Ns=Rank%7cAsc
12-17-2011, 09:35 AM
#7
Melting Slicks
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168 teeth ring gear=11" clutch
153 teeth ring gear=10.4" clutch
You can tell whether you have a 10 or 26 spline input shaft by unbolting the driveshaft and counting the output splines.
27 spline output will have a 10 spline input.
32 spline output will have a 26 spline input.
153 teeth ring gear=10.4" clutch
You can tell whether you have a 10 or 26 spline input shaft by unbolting the driveshaft and counting the output splines.
27 spline output will have a 10 spline input.
32 spline output will have a 26 spline input.
12-17-2011, 10:45 AM
#8
Instructor
Thread Starter
Thanks for the tip on how to determine.
I'm guessing that the flywheel will need to be rotated manually without starter in position and count 'em that way?
I'm guessing that the flywheel will need to be rotated manually without starter in position and count 'em that way?
12-17-2011, 05:35 PM
#9
Instructor
Thread Starter
Thanks gkull and 69 Chevy, very helpful info you have provided.
She's a 4 sp but again not sure how to determine if it's an M20 or M21. Knowing it's a 153 flywheel now provides me with the opportunity of ordering the parts and having them arrive same time engine does - it's currently on the water in transit to Oz.
She's a 4 sp but again not sure how to determine if it's an M20 or M21. Knowing it's a 153 flywheel now provides me with the opportunity of ordering the parts and having them arrive same time engine does - it's currently on the water in transit to Oz.
12-19-2011, 09:01 AM
#10
Melting Slicks
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As long as the guts inside haven't been changed, you can tell close from wide by deciphering the code on the trans like mine from above.
The last letter in the code line:
A=M20 wide ratio
B=M21 close ratio
C=M22 close ratio HD 'rockcrusher'
You could also put the trans in first gear, mark the flywheel and driveshaft/output yoke. Wide ratio M20 has a 2.52:1 ratio while both the M21 and M22 close ratios have 2.20:1. Flywheel will either turn 2.2 or 2.5 revolutions for 1 revolution of the driveshaft. That's a positive way to know short of removing the sidecover and counting the mainshaft gear teeth.
Last edited by 69 Chevy; 12-19-2011 at 09:11 AM.
12-20-2011, 05:49 AM
#11
Instructor
Thread Starter
As long as the guts inside haven't been changed, you can tell close from wide by deciphering the code on the trans like mine from above.
The last letter in the code line:
A=M20 wide ratio
B=M21 close ratio
C=M22 close ratio HD 'rockcrusher'
You could also put the trans in first gear, mark the flywheel and driveshaft/output yoke. Wide ratio M20 has a 2.52:1 ratio while both the M21 and M22 close ratios have 2.20:1. Flywheel will either turn 2.2 or 2.5 revolutions for 1 revolution of the driveshaft. That's a positive way to know short of removing the sidecover and counting the mainshaft gear teeth.
12-20-2011, 10:08 AM
#13
Drifting
The pedal isnt too stiff, it hasnt chattered at all, and even though I'm running a healthy big block and drag radials the clutch hasnt slipped.
12-20-2011, 01:20 PM
#14
Burning Brakes
That is good to know. I was considering the Powergrip, but also the Force 9.5 (but I think it may be overkill). I also considered the Centerforce, but the local speed shop says they remove the balance weights because they make noise?? Thanks for the input. Not quite ready for a clutch, but just thinking ahead....
12-23-2011, 03:02 AM
#16
Instructor
Thread Starter
POB030A February 3rd Production and an M20.
Even though she's an early 70, and most likely a 10 spline input, I'll take your advice and drop drive-shaft to count the output splines.
And good news also, she is a matching numbers tranny...
Thanks
Last edited by BigBadBorry; 12-23-2011 at 03:38 AM.
12-23-2011, 08:55 AM
#17
Melting Slicks
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I would be surprised to find a numbers matching 1970 Muncie to have a fine spline OEM input shaft. Although, unless you know your car's history, things could have been changed in the last 42 years.
Mine started out as an M20 but I installed replacement gears years ago to make it an M21. No one can tell from just looking at the exterior.
Mine started out as an M20 but I installed replacement gears years ago to make it an M21. No one can tell from just looking at the exterior.
For the 1970 model year, there were two major changes to the Muncie four-speed. In previous years only the M22 transmission had a drain plug, however, beginning in 1970 all Muncie four-speeds now had a drain plug. The second change was the addition of a fine-spline output transmission assembly for only the Chevelle M22 applications. This required use of a new tail housing, which was specific to the Chevelle M22 applications for the 1970 model year. All other transmission assemblies including Corvette used a course spline output shaft. The 1971 model year marked the last of the major changes to the Muncie four-speed transmissions. The input and output shaft both changed from course spline to fine spline. This carried over for all Muncie four-speeds.
12-23-2011, 09:57 AM
#18
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St. Jude Donor '05
but the local speed shop says they remove the balance weights because they make noise?? T
They dont make noise, leave them in there.
12-23-2011, 10:09 AM
#19
Instructor
Thread Starter
Thanks 69 Chevy, I think that I can safely place an order with Summit for a Centerforce DF271675 kit and have it Fedex to Oz. Delivery will coincide with my 383 - I'm getting very impatient...
- I'm getting very impatient...
12-23-2011, 11:24 AM
#20
Race Director
I have had the same Centerforce DF in 3 motors, 400hp 350ci, 550HP 406ci and my current engine and both the 406ci and my 427ci you are looking at 500-600ft/lb of torque. Ask that "mechanic" if he can store the wieghts for you where the sun don't shine
