New clutch, what size?
12-04-2011, 08:55 PM
#1
Staging Lane
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New clutch, what size? In to process of mating a 5.3 to a SM465 trans. I have ordered the sachs flywheel NFW1050, which is for a later model 4.8 or 6.0 engine that also had a manual transmission. This is to make up for the missing .400 of an inch in the newer engine.
I've yet to recieve it, however I'm looking at clutch options ahead of time. The clutch I run now behind my sbc is a stock, 12" clutch that came on any half ton or heavier pickup truck from the 80's, running the same transmission. I would like to purchase a new clutch of the same size since this truck does a lot of towing, offroading etc, and I feel as though a 12" is designed for just that.
From what I've read from conversions, everyone else runs an 11" clutch. While this is an option, I'd hate to be barreling down the highway, having the clutch slip out on hills because its to small, or spend a small fortune on a high-performance 11" clutch to match what a stock replacement 12" would do.
Now hear me out, because I don't have any parts to compare. But since a 12" clutch came on a 163 tooth flywheel behind a sbc, would it not bolt up to the new sachs flywheel, which is also 163 toothed? Or would the bolt pattern on the flywheel be smaller for some reason? Is the pressure plate of a 12" and 11" the same, with just the clutch size being different, or are they perfectly matched to their specific size?
I've yet to recieve it, however I'm looking at clutch options ahead of time. The clutch I run now behind my sbc is a stock, 12" clutch that came on any half ton or heavier pickup truck from the 80's, running the same transmission. I would like to purchase a new clutch of the same size since this truck does a lot of towing, offroading etc, and I feel as though a 12" is designed for just that.
From what I've read from conversions, everyone else runs an 11" clutch. While this is an option, I'd hate to be barreling down the highway, having the clutch slip out on hills because its to small, or spend a small fortune on a high-performance 11" clutch to match what a stock replacement 12" would do.
Now hear me out, because I don't have any parts to compare. But since a 12" clutch came on a 163 tooth flywheel behind a sbc, would it not bolt up to the new sachs flywheel, which is also 163 toothed? Or would the bolt pattern on the flywheel be smaller for some reason? Is the pressure plate of a 12" and 11" the same, with just the clutch size being different, or are they perfectly matched to their specific size?
12-05-2011, 12:23 AM
#2
I would say go with the 11 inch clutch, just get a hevay duty one. I know autozone has a lifetime warranty HD clutch for under $150. That being said it isnt a HAYS, Ram, or Centerforce but if you break it in right it will do the job.
Another point worth mentioning is that i am swapping a 4 speed/5.3 into an 81 camaro and i got the Sachs 1050 flywheel too. When i bolted everything up there was plenty of extra flywheel area left with the 11" clutch bolted up. You probably could run the 12" disc, which i never even heard of til i read your post, Im assuming your running a truck bellhousing? You would prob have even more room than i do, and I am using a regular BBC "621" bellhousing. Hope i helped! Good luck man!
Another point worth mentioning is that i am swapping a 4 speed/5.3 into an 81 camaro and i got the Sachs 1050 flywheel too. When i bolted everything up there was plenty of extra flywheel area left with the 11" clutch bolted up. You probably could run the 12" disc, which i never even heard of til i read your post, Im assuming your running a truck bellhousing? You would prob have even more room than i do, and I am using a regular BBC "621" bellhousing. Hope i helped! Good luck man!
12-05-2011, 05:01 PM
#3
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Thanks for the invaluable information. Really want to stick with a 12", since I am running the truck bellhousing; if at all possible. Planning on ordering a clutch from a local parts store, so if it doesn't fit, its easily returnable. We'll see how it goes.
which cluch bolts did you use? metric or sae 3/8ths? I can only find conflicting info on this. Won't have the flywheel in my possesion for another two weeks or so.
which cluch bolts did you use? metric or sae 3/8ths? I can only find conflicting info on this. Won't have the flywheel in my possesion for another two weeks or so.
