I can't comment on the manifold/steering gear but there is a lot of info in prior threads. The 350 transmission bolts directly to the engine, no bellhousing but the bolt pattern may not match. You will also need a flex plate that will bolt to the crankshaft and match the torque converter. The '57 V8"s front mount was with 2 "birds legs" on the front of the block.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy