Have the shop check the cam and lifters for excessive wear---it's a lot cheaper to have them replaced (if they turn out to need it) while the head is already off. Pull each lifter out, one by one, (it's very important they go back in their original holes) and examine it, (bad ones are pretty obvious) then put the pushrods back in and rotate the engine by hand and measure the distance they travel. They should all be pretty much identical, with maybe a slight variation between intakes and exhausts. If one or more come up short, that lobe is badly worn and the cam should be replaced. The cam and lifters should always be replaced as a set.

Also, make sure to have hardened valve seats installed, if that hasn't already been done. Then you can use unleaded gas with no worries.