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whats the difference between a bb and sb as to bellhouse size and bolt pattern and clutch diameter recommended? any other differences to be noted when comparing drive line components? my only experience is with sb, and i'm considering building a bb. what clutch would you recommend for a medium output bb?
jeff
BB & SB bellhousings are the same pattern & I believe that they are interchangeable. As far as clutches I believe that the BB used the larger 11" & the sb used both the smaller ( I think 10.5" ) & the 11" depending on the original application.
Hope this helps a little.
Here is the basic; BB and SB are the same for the bell housing and the dimentions from the bell housing to the front motor mount are the same. The cross section of the BB between the motor mounts are the same. The BB will sit higher and wider and approx 1.5 inches longer.
BB's are on the aversage 150 lbs heaver. Clutches depend on the application and output of the engine.
SB motors came with a 10.5 and 11 inch clutch. They both use the same bellhousing and can use the same clutches. Which clutch is a matter of how hard you are going to abuse it and how much power you are sending through it.
BB and SB share a common bellhousing and bolt pattern.
Even a straight six and 90 degree V-6's 4.3/4.8 have the same pattern and will bolt right up. Same deal for starters, just have to match the starter "foot" to what size flywheel you use. I'd look at everything closely, for peace of mind's sake and make sure you aren't trying to put an 12" flywheel in an 11" hole. Wasn't directing that last statement towards anyone personally but it was for others that may be following the post or have a similar situation. Good luck
The larger and smaller setups can (and were) used on both BB and SB. The only thing you have to worry about is keeping them together. You can't mix and match. No big bellhousing with small clutch and or starter etc. It is all or nothing. BB or SB is not important.