What would the size of allen head bolts in my 94 LT1 Vet?

 

ALLEN??? You sure they're not TORX head bolts???

At any rate, you better make absolute certain, cause you only get one chance at 'em. Make absolutely sure there's no 'jam' inside the bolt head, to stop the socket from seatin' good in the bolt. YOU DO NOT WANT TO ROUND OUT A BOLT DOWN THERE!$!$!$

Hope you fared well - I see the OP date........