The Vette intake is for a 235 with a very small cam, 24.5 degrees of overlap, and tweaking the carbs will be needed with that cam.
All 1937-early 1954 216, 235 and 261 camshafts are steel, and must only use compatible chilled iron (“milk bottle”) tappets. Biggest journal is 2.028".
Visual camshaft ID: http://tinyurl.com/3c3obzk
Late 1954-55 engines use large journal steel camshafts. Biggest journal is 2.154".
1956-1963 235 & 261 camshafts are cast-iron, and must only use compatible (common) cast-iron tappets. These are hard all over (but softer than the chilled iron’s contact surface).
What years show on the cam card?

The Powerglide engine used a 1/16" larger intake valve, will it help? IDK.