[b-man]

It all boils down to you’re best off staying with a factory performance cam and stock 1.5:1 rockers if you’re not going to pony up for the valvetrain upgrades required to run higher spring pressures or higher ratio rockers.

Trying to make the factory designed non-adjustable valvetrain into one that’s adjustable can’t be done correctly unless you get rid of the factory bottleneck studs whether they’re press-in or screw-in style. As already pointed out above the stud loses support at the bottleneck when you move away from the stock non-adjustable rocker nuts.

Will the bottleneck studs break if you run an aftermarket cam with higher lift and non-stock adjustable nuts or polylock nuts? Maybe or maybe not, gamble if you like.

On an extremely limited budget?

Then stick with either a factory cam or something close that doesn’t require an adjustable valvetrain.

Even with the 068 cam the press-in studs can back out, especially so if the heads have been through a shake-and-bake modern machine shop cleaning process which can tend to loosen up the factory press fit on the studs. The dealers did stock slightly oversized replacement press-in rocker studs so it wasn’t all that uncommon to find some of the studs backing out when these cars were new.

You always hear about valvetrain failures of one kind or another from people who put a big cam in their engine but didn’t address the other things required when you do that.