What size bell housing do I need
 

I have what most would probably think is a dumb question but I'm a rookie so , I'm looking between two different transmissions right now but am unsure of what bell housing (size part number) I will need to match the tranny to the motor also what flywheel I will need and clutch. I have a 1973 small block 350 motor and am looking between a m20 wide ratio and a m21 close ratio, this is going into a 77 vette, also what one would be a better fit for me I won't be racing but I do like to put the peddle to the floor and get there fast occasionally.

I don't believe there is any difference in bell housings for those applications. If you are drag racing, you may want to investigate equipment rules to make sure the housing you buy will meet their requirements.

No I'm just going to be using this for Sunday driving, here's what I have found and just want to make sure it works before I spend the money he wants 1500 for this setup and I'm not sure if that's good or not. And what else would I need if something is missing.

Here's the listing

All parts are either new or in excellent condition. New 10 1/2" clutch. Hurst shifter with linkage for the transmission. All this was to be used in a show car, 1966 Chevy Nova with a small block engine.This IS NOT an M-22 Rock-Crusher.
this transmission is an M-20, wide ratio. The cluster gear tooth count is 25-22-19-17. Output shaft is 1 1/8" w/ 27 teeth. First gear 2.52:1, second 1.88:1, third 1.46:1 and forth gear is direct.
also have the hydraulic throw out bearing parts from Wilwood

Sounds like a lot of money for changing a clutch and bell housing. But, I'm an 'old guy', so my connotation of the value of money is likely different.

I would think $1000 would be on the high end for the bell housing, clutch, used shifter and labor.

No this is a complete transmission, clutch, shifter mechanism, Pressure plate and all, but I'm looking at it and the shifter is the tall style so I do not believe it would work unless they are universal,

The Hurst shifter has a stick that just bolts to the main body of the shifter. There are loads of different sticks, including one that looks like the original GM supplied one with the reverse lockout trigger. It's not functional on the Hurst, but looks just like the factory one.
IIRC, there are different number GM bellhousings, and I think the number you got is dependent on which flywheel/clutch was used. They all had the same bolt patterns, but the diameter was different.

So if I have this correct the actual hurst shifter will work from any car just have to change the stick itself and the 10 1/2 clutch that I get with my transmission will bolt right up.

Kuhndar, The 327 engines used the 10 1/2" clutch and a smaller diameter bell housing. I think that, that is the setup this guy has. Vettes in 69-up had a 350 and used a larger bell housing and an 11' clutch. The 327 10 1/2" flywheel has 153 teeth. The 11" 350 flywheel has 168 teeth. You need the larger bell housing for a 350. Hope this helps you. Lou.

The flywheel might change [bolt pattern] with a different diameter clutch/disc, but the bellhousing should be the same.