I am wondering why someone would put 3973487x heads on a 3970010 block ? will it increase performance, or be more efficient, or did the guy just throw on these heads because he got a deal ? I am not really a mechanic just some one trying to figure out what I am working with. The guy who built this engine died, and i bought it from his friend who was selling his stuff, and had no clue. Hopefully this engine will get my 85" elky back on the road but I am beginning to worry about smog issues in So Cal. I have a couple of friends who say they no guys who will pas anything for $200. I would. prefer to be legal . Any tips ,for a real novice on a shoestring, makin do .
thanks Pappy.
Performer mani
Roches Qjet
OE exhaust

Don't understand, what is wrong with the heads which very well could be stock on that engine.

I was told once by a man in the know, the smog place will not take apart your engine to see if all parts are compatable for that year. If every thing is on it that should be it will appear stock. But it must pass the emissions test.

I am hoping there is nothing wrong, just trying to find out if they were stock or if they might have been an upgrade as internet sights say they have somewhat larger intake ports then other heads of that era. I really am just learning so If it sounded like a stupid Question it's because I am curious, and maybe a little stupid, but any opinions or info is welcome, I am a sponge. pappy

Thanks for your imput, i am working in tha direction.
Pappy