Does anybody know the weight difference of an XR upper vs an SCX upper?
 

I've added SCX uppers to my 388 Hustler and was wondering if anybody knew how much more weight the upper and 3 more quarts of oil adds per drive.

Maybe check the Imco site, a guess would be 50 lbs

are you running a sport master or sc lower, I read that the complete scx drive weighs 80 lbs more than an XR and is set back 3/4 of an inch

Is there going to be any speed loss going from a XR upper to the Imco scx upper ? There’s probably a lot of variables in that question but is there any real #’s one has lost going to the scx upper ?

Definitely a loss,

I thought there was zero loss unless you used the fat lower...

thats my understanding also

F-2 - Im running sport masters. Thank you for that info.

Larger gears, shafts, cone clutch, more lube, bigger cavitation plate, more drag, heavier, harder to turn. Possibly a necessary evil if you're blowing XR's apart.