OK my son & one of his buddies got in on a engine swap of a 92' f1504x4.
converting a 86' engine to a 92' 351/5.8 so pretty much I'm out of the loop.
They been working after hours most of the week but with it being Sooo hot, progress is slow.... the owner wants his truck ASAP

basically they pulled a tired 5.8 /351 out and swapped in a better (possibly), engine from a 86'. They swapped the intake from the 92' engine but used the heads from the 86'.

the question is... what is this exhaust port out the front of the heads (both banks) & what size are those threads to plug them???...(guessing 5/8-11 threads or are they metric?), so they can plug them.

the 92' heads have some sort of insert threaded in them....kinda doubt that they can be removed, gonna suspect they were lock-tighted in.?? IDK

Have they short stepped their way to a bunch of headaches by not keeping the 92' heads?

appreciate the help/ & insite

 

maybe to help clarify...it seems to be some kind of EGR port

 

You sure it isn't for the air injection system (smog pump)?

 

thanks for the reply!
oh man, sorry, talk about leaving out details... exhaust came shooting out of them.

it is the bigger hole above the frost plug

 

That's where the air injection goes - into the exhaust..........

 

you wouldn't happen to know what size those hole are??? or what parts # is need to plug them?