I need a master cylinder for my '74 scamp. it a manual brakes with front disk and rear drum. Most places I look have different bore sizes. What is correct?

I have (had till it was hit) 74 A manual discs/10" drums (same as you/& 7&1/4 I'm assuming) in a 65 dart with the 1&1/8 alum M/C & it brakes flawless tho that is reportedly too large of a bore dia & others have reported way too much leg effort needed with that dia but it has worked for me (& I ain't that strong). Here's a BTT for ya since you ain't getting no love on this request.

As far as I know should only be maybe 2.One for drum/disc and one for drum/drum.Rocky

Chrysler '74 parts book shows part# 3580146 for manual disc/drum but no size is shown. Rockauto.com shows several brands and the size as 1-1/32". The Chrysler part# crosses to a Dorman# that is one of numbers Rockauto shows as 1-1/32. From this info I would say 1-1/32 is the correct size.

If you have the old master just pull the guts and see what size it is.They are all marked on the rubber cup.Exchange they dont care if its apart or not.Rocky

my wagner master catalog says 1 1/32" for manual brakes {F83578 for drum and F88787 for disc] and 15/16" for power [F80266 disc/no drum brake master listed]. this is 74/76 applications. hope this helps.

I pulled the master cyl off and it measures 1.060 right at the opening. I didnt remove the snap ring or the plunger so Im gonna assume it is the 1-1/32 bore. It originaly came with a 8-1/4 rear, now it has a 8-3/4. It stopped fine just they cylined leaked out all the fluid over the winter.. Ran down the firewall and messed up my pretty yellow paint.