ok so long story short i have 3 351long blocks and it seems that the bolt on the right side for the lower plenum likes to brake off in the head and so i took one of the heads and put it on my rebuilt motor but yesterday i was bolting up the brackets and noticed the alternator bracket wasnt bolting up upon furhter inspection noticed that the bolt hole went straight through and had huge threads so i looked at the other heads and it seems the head i put on appears to be from the other side and the hole is for the air tube in the back of the heads (i put bolts in the rear holes not noticing there was a plug) and i also noticed on the other heads they all have what appears to be the plug in this hole so my y quesetion is are the heads reversible? i know when i put the heads on all holes lined up pushrods went in straight just wondering any feed back qwould be helpful thanks

 

Yes the heads are reversable.

 

I had a similar problem with a set of new AFR heads, one side had the big air tobe hole in back and the other had it in front. Found some thread reducers at Fasenal that go from the 58-11 to the 7/16-14 for mounting the front brackets. Five cost $15. If you are close, I could send you one for the cost of shipping, don't know of a cheaper place to find them. AFR wanted $15 a piece.
Dave

 

But only if he takes the threaded insert from the other head and screws it into the head that's missing it. Or screws a new insert in there.

 

That was exactly my question after some research and comparison the heads are identical thanks you guys for the replies I found the plugs on jegs bad a couple other sites as well they call them thermactor plugs and thank you for the offer to ship unfortunately im not to close to ya