EDIT: Is this the crate engine you have? If it is new, it would seem the dealer that you purchased it from should make good on getting you a timimng cover with a tab included.
Originally posted by mcgrsr
how do you set the timing if you don't have a timing tab on the cover i don't think there is one available. This is a brand new crate from gm ...
It seems odd that a new GM crate engine would come without a timing tab. If this is your engine, it has an 8" balancer. Perhaps a simple bolt-on timing tab is available for that particular balancer, that would work with the composite timing cover.
EDIT: Now that I think about it more, since the engine is in the car, changing the timing cover, even if provided at no cost by GM, will be a royal pain. If a bolt on timing tab is not available, I would do as Johnsongrass suggested and JB Weld a makeshift tab to the timing cover.
Best of luck!