If you already have a V-8 and want to go back to a 6, the cheap way out would be to go with a 250 or a 292 which will bolt up to the bellhousing you have now. If you want the 235 you'll need to also get the bellhousing and everything in front of it,
Scott

Scott Ward

2 1948 1.5-ton Loadmasters
The red one and The snow pusher
1 1950 3100
1 1955.1 Chevy 6500
1 1954 Chevy 6500 2-Ton
1 1955 1st Series COE 5700
1 1963 K20 (454)
1 1964 C10 (350)
1 1951 1.5-ton Dump Truck
1953 and a 1956 Ford F800

Raising a teenager is like trying to nail Jello to a tree!