Originally Posted by fastmark
Originally Posted by dragon slayer
Originally Posted by DAYCLONA
Originally Posted by 71ragtop
What's the difference between a small block and a big block e body 4 speed transmission thanks!



There's 3 4spds, smblk, B, RB... 340/23 spline, 383/23 spline, 440/426 18 spline, there's also 2 different input shaft bearing flange diameters, so depending on the bellhousing being used, transmission being used, there's a lot of room for problems to arise when buying/sourcing parts, all the E body transmissions use the tailshaft shifter boss, the transmission external dimensions are all the same regarding bolt patterns/trans mount/ overall length/etc... many combos are possible with aftermarket bells, or machining factory bells..... I have a HEMI 18 spline 4spd behind my 340/6 with a factory bell and an 11 clutch, technically not doable, but with custom machining made possible..

Mike


What is different between a 340 23 spline and a 383 23 spline?


All 340 23 splines had the 307( small) front bearing in 1970 up. I think 1970 started with 383 23 splines having the 308( big) bearing. It may have been just the rear tail housing bearing. I’ve got all three at the shop so I can look. It’s been awhile since I had a 70 383 trans apart. I’m pretty sure the 69 had the small bearing but the larger od on the bearing retainer. Brewers will know. Tell us what trans you are putting in what applications.



The E body 383/23 spline will have the larger input bearing retainer...

Mike