I bought a 22r motor and the guy said he thought it was a 85. I tore it down and there is a dual timing chain in it. I thought they were in 20r. Now im thinking someone already made it a 20r/22r hybrid but not sure please help. I also got to get a rocker arm assembly which one should i use 20r or 22r?

 

dual row timing chains were available in pre-1984 22r's, and also all the 20r's.

possiblity he had replaced the head with a pre 1984 head? or maybe he did go ahed and swap a 20r head on there.

 

I think you can install the double chain on any 20 or 22R if you get all the parts,gears,guides, oil pump spacer etc. But Im no expert

 

Flat or domed pistons? Round or pear exhaust ports? Round or square intake ports? And by 22r you mean it's a carbureted engine correct?

I am assuming you want to know so you know which gasket kit to get correct?

 

This ^^^

Thats the only way you will know for sure. The ports will tell you what is on there for sure...