We have a 70 barracuda slant six parts car and I was wondering if I could use the 3 speed tranny in it for my 318 in my 70 challenger? What would it take it or will it not work? I trying to build this with parts that we have kicking around the shop.

Nope, slant 6 uses different bellhousing pattern than small block v8.

What if I use a 318, 340 bell housing would it work?

yeah. that trans would work, if you have a smallblock bellhousing.

yes, most likely an "A230" and if so it will have "A230" on a machined pad on one side of the trans. It is synchro'd in 1st & is a tough trans. The /6 oe ones are 3.08-1st, 1.70 2nd. The oe V8 one is 2.55-1st. 1.49-2nd.

yes you just need a smallblock bellhousing. most of the 4 speed bellhousings i have seen also have the 3 speed mounting pattern on them too.

I have a v-8 three speed bellhousing if you need it part number 2536940

The later 3 speed bellhousings have dual pattern for both the 3 speed and 4 speed. Notice the 3 speed is a square pattern, while the 4 speed has an offset bolt hole. My experience is that the dual pattern was introduced around 1972. Any later bellhousing, including the pretty abundant ones from trucks, should work. I have several.