There is nothing weaker in a 2bbl trans than a 4bbl trans for the same model year. The main difference between them is to accomplish shift quality and shift timing. Between years there were changes - we made improvements for high horsepower and torque and durability, but a properly built 383 2bbl trans behind a 440 drag motor making north of 500 hp is a piece of cake.

Think about this for a second. No one used billet parts - none - back in the 70's and 80's and those drag cars were going low tens and high to mid 9's. Race converter and a TA Cheetah was the "soup for the day" and no one was failing units. And 99.9% didn't have bolt in overrunning clutches either. Everything was relatively new back then - parts wise in the transmissions being used.

The point i am trying to make - most guys can successfully use a "standard" 727 if it is properly built. The biggest obstacle is understanding what hard parts to throw in the garbage versus reuse.

The best core to start with is one that came from a car that was crashed and before it was crashed came from Ma or Pa kettles car - never got beat on and probably never saw overheat conditions. Sorry for the verbose reply - but you asked.

Probably the vast majority of street racers, cruisers, bracket cars can use a 4 disc front drum, 3 or 4 planetary pinion carriers, flexible front band, non- billet servo parts IT YOU USE GOOD PARTS.

As for the 904, 998, 999 - number of clutches and band widths - the main unit's differences.

Then again there are guys (and gals) that can ruin an anvil in a sandbox with a rubber hammer.