the block i used was a 83 or 84 because it came with the single chain.. don't know all the history.. the 20r head well bolt on to the 81-84 block.. it's just like the 20r block only a bigger bore.. they changed the block in 85..then it's pretty much the same until 95 i believe. thats the years efi was used with.. a few did have carburetors.like my 86. if I'm wrong let me know..
