Does anybody know for sure the difference if any on a 1970 Cutlass SX L-31 and W-32

 

From what I've read:

W-32 had a different carb (7040257 vs 7040251 on L-31), different trans (OG code vs OD on L-31), larger valves, different cam, different distributor...

 

These two 455 engines were set up for different purposes and behave differently. The more performance oriented W32 was the base 442 455 that used the OG TH400. The L31 was the big car 455 and used the more relaxed OD TH400. The biggest difference between the two engines are the camshaft, the size of the intake valves, the carburetor jetting and the advance curve on the distributor.

I believe that there are at least a couple threads on this site discussing the three 1970 SX 455 engines.

Terry

 

Was the L-31 engine in the sx different than the L-31 engine in my 442? My 442 100% numbers matching with the big valves E heads and the OG trans.

 

From what I know, and it may not be totally accurate, is that the W32 was the same as the 455 4bbl, as used in the 442, which had 10.50:1 compression (365hp/500lb ft.), while the L31 had 10.25:1 compression (365 hp/510 lb ft.). But, the horsepower and torque are given at different rpms.

 

Yes, they are different. Again, the L-31/OD TH400 in your SX was the same as the 455 used in full size cars like the 88 and 98. Your 442 has the same engine/OG trans as the W32 SX (this same engine in the 442 was not designated with the W32 code however.). They're not the identical drivetrain.