mserges

I am installing a TKO600 behind my 5.3L LS engine. I am using the Sachs NFW1050 flywheel, 621 bellhousing. I was previously running a T5 with a truck bellhousing on this setup and an old school BBC 11 inch clutch. When I pulled it apart I noticed the clutch face was not making full contact with the flywheel. The lower 20% of the clutch was inside the mounting circle of the flywheel. This was a known issue when I originally installed the T5, but it was OK for what I needed at that time. Now that I am going to a stronger transmission I am looking for a clutch set that fits this set-up. I read many posts and it seems the recommendation is to go with an 11 inch LS clutch versus the old school BBC clutch. One thread suggested using a 12 inch clutch, but was not clear if it would fit in the 621 bellhousing. Can someone tell me what will work and what part numbers to look for to put this back together? I suppose the old clutch will work but will continue with the same issue. I have attached a picture from another post that shows what I am seeing on my clutch plate....Thanks!!!

garys 68

iTrader: (1)

Main reason to use the sachs flywheel is for the 10 spline trans.
A 98-02 f body flywheel/clutch will work with a 26 spline TKO. Or your exising will easily hold a 5.3.
https://ls1tech.com/forums/conversio...-ls-motor.html

jmd

iTrader: (4)

Mock up an LS1/LS6 clutch and flat 97-04 Y/F-body flywheel. Or the LS2/LS7 and dished flywheel.

If the PP finger height works with the Chevelle throw out bearing you failed to mention in the thread, I see no reason to carry on with the 11" older truck version clutch.

IIRC, the mad dash to use the 1050 and truck clutch was they were cheaply available, not that they were functionally ideal.

Don't forget to verify pilot bearing engagement.

mserges

Thanks garys 68!! Appreciate the quick response. I believe you helped me back in 2011 put the T5 package together. Will a 98-02 f body clutch mount to the SACHS 1050 flywheel and fit better? If I understand the last part of your response....No big deal that the full clutch face is not contacting the flywheel? The guy helping with the swap just suggested this would be a good time to address what he saw when we pulled the clutch plate....If no big deal, then I might just leave it alone....Thanks!!

mserges

Thanks Matthew for the quick response!! I am looking for clutch options that might fit the SACS 1050 better. Wasn't planning to replace the flywheel unless absolutely necessary. Never had a problem with the T5 setup even though the full clutch face was not contacting the flywheel. Kept seeing LS clutch with the NFW 1050 and was trying to confirm if the LS clutch is indeed a better fit....My throw out bearing is the clutch stock one for an MU 5505-1A clutch, which is listed as an 11inch BBC clutch....Thanks!!

garys 68

iTrader: (1)

I'm not sure which combinations will fit in a 621 bellhousing. The thicker sachs flywheel was intended for the larger truck clutch, but that was also intended for the larger truck bell. The LS1,2,5,7 thinner flywheel/clutch combo also fits in the 621 bell.
But keep in mind, your current combo has the same clamping force regardless of contact area. With a 5.3, I doubt you're beyond its limits.
My $0.02.... keep your current combo. It might wear a little faster than if it had full contact area. It's worked well til now....correct? If you're still worried, go to the 98-02 f body flywheel/clutch combo, but you'll also need a longer throwout bearing.

mserges

Yes the current setup has worked fine so far. As you advise, I think I'll stick with what works. When it's time for a new clutch I can always revisit. Thanks for your help!!