The original V-8 frame mounts are not in the same location as the 235 they are an add-on to the frame cross member. There is a bracket which protrudes below the timing cover on the 235 engine. Earlier trucks & cars had a mount on that very point.
You could use something like a rear trans mount from a 350/400TH or something similar. They are about 1 1/2" high and about 3 1/2" long. You would have to drill holes in the crossmember and probably the bracket on the engine. There are also aftermarket crossmember mounts available for V-8 conversions which utilize the center mounts. However, I'm not sure If it would work for the 235 center mount.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine