Distributor Drive Gear Sizing

[CamBiscuit]

Guys, I am looking at ordering a twin plug distributor from JB Racing and want to make sure I get the right one.

This will be going into a 2.4 7R case which has the 30mm distributor hole.
There are two gear sizes - small with a 25.15mm gear and large with a 25.75mm gear.

I believe I will need the small gear version but could someone please confirm?

Thanks

Cam

[CamBiscuit]

Bump!

This engine will have a shortstroke 66mm crank..... not sure if that makes a difference?

Can someone measure a 70/71 dizzy and a 72/73 dizzy if you have 'em lying around?

Thanks

[gled49]

all distributor drive pinions for clockwise rotation up to 1977 were the same in points distributors also 76 turbo. the smaller of your two pinions. in 78 with the general use of eletronic iginition, all distributors were counter clockwise rotation and not interchangable. in 84, carreras with crank trigger went back to colckwise rotation but with the larger of your pinions. they are not interchangable. if brass gear on the crank is worn enough for the big pinion to go in the case it will tear the brass gear off the crank when put into use. gordon