There is more involved than just changing the mounts. Nothing from the 235/261 engine will fit on the 292, specifically the flywheel, bellhousing, throttle linkage, & starter. In addition the later bellhousing will not mount to the 52 crossmember.
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