Originally Posted by 63 340HP

With you being new to Corvettes, we should clarify some cam identities (with the help of the reference chart below):

The Duntov cam was Zora's solid lifter design from his experience building engine components, often called the 097 cam based on the last three numbers of the part # listing. It was the Special HiPo (SHP) Corvette cam from 1957 to 1963. It was your car's original cam. The Duntov 097 cam lift is a mild .394/.400"

The 30-30 cam was GM's solid lifter Corvette SHP cam starting in 1964 and the Z28 302 cam, often called the 346 cam based on the part number. The 30-30 is an early computer designed cam that GM dyno tested to beat the Duntov cam. The 30-30 cam uses the same intake and exhaust lobe profiles, and lift is .485/.485"

The 350hp/327 cam was GM's hydraulic SHP (L79) Corvette cam starting in 1966, often called the 151 cam based on the part number, an early computer designed & dyno tested cam. The 350hp cam uses the same intake and exhaust lobe profiles, and lift is .447/.447"

The 300hp/327 cam was GM's hydraulic HP Corvette cam starting in 1966, often called the 929 cam based on the part number. It replaced the earlier 250 & 300 hp cam. The 300hp cam lift is .390/.410"

With the 350ci engine displacement change, GM revised the SHP cams in 1970, with the solid lifter cam being the LT1 "178" cam, and the 350hp hydraulic cam being the L46 "962" cam (the preferred GM cams if you run GM exhaust manifolds). These later cams evolved from dyno testing to use different intake and exhaust lobe profiles, with an intake duration that is shorter than the exhaust duration to better move exhaust gas through restrictive manifolds. The part numbers are not in the chart below, as the chart ends in 1969.

The points to take to heart, and back to your machinist (besides the correct name references), is that no factory installed GM small block cam had lift taller than the .485" lift in the 30-30 cam (his comment of a .500+ lift factory cam is incorrect). GM did not find power increases with higher valve lifts during their testing with stock as cast heads (although GM did offer an over-the-counter PN 3927140 "Off Road Mechanical" race cam that worked with ported heads and tube headers with higher .493''/.512'' lift).

All of these GM cams worked with stock GM rocker arms and fit under the stocked finned SHP Corvette script valve covers (even the 140 race cam).

Considering the rough rusty look of your original engine photo, I expect the original rocker arms look pretty sad and new rockers must be purchased anyway?

If new rocker arms are needed, a good forged or cast roller tip rocker arm is preferred over stock rocker arms or roller tip stamped steel rocker arms. The better forged roller tip rocker arms have roller bearing trunions rather than the stock style ball and socket pivot bearing. All of the stud mounted rocker arms fit under the stock finned valve covers, but not all locking adjustment nuts fit (some brands locking adjust nuts are too tall, but short locking nuts work). It is only with the extra height of a stud girdle that the factory finned valve covers are guaranteed to come up too short.

Talk to your machinist, and keep the project moving along (the Corvette will easily outrun your tri-five cars).