Hey all Happy Friday 😀
Just wondering what the differences are between a '72 "baseline" 455 and the U code 455?

 

Nothing. The letter "U" was simply the code used in the VIN to signify the RPO L75 250 HP 455 with TH400 as installed in the Cutlass line in the 1972 model year. The letter "V" was used to signify the 270 HP version of the 455 with four speed in the Cutlass line. The difference between the two was primarily the camshaft.



The other versions of the 455 shown in that table were used in other model lines - the 225 HP L74 version in the full size cars and the 250 HP L78 version in the Toro.

 

Got it..so what were the differences in the W30 and the U code?

 

For 1972, it was cam, carb jetting, and distributor advance curves.

The 1972 U-code L75 455 (AT motor) got the 258/272 deg cam.
The V-code L75 455 (MT motor) got the 286/287 deg cam.
The X-code L77 (W30) AT motor got the same 286/287 cam as the V-code MT motor.
The X-code L77 MT motor got the 294/296 cam.

 

I've noticed you are a excellent source for Oldsmobile engine information.

 

He knows a thing or two..........Theres always one guy........