73 318 will J heads work???
71dmn has a set up that takes advantage of the J heads and has a shot of N02 to get going. Are you going this route?
What is your build and target? This is the question we need answered so we know what exactly a good recomendation is.
Heres the thing. Most people are not going to use a preped 318 head on there 318 when a 360 hed is cheaper to use dispite the fact that it will not work as well. Porting a head, even just a good bowl prep and valve cut back and job will out spend a stock J head. So people will opt.for a set of 360 heads @ around 2 - 3 hundred and go from there.
If your 318 is rebuilt new with zero deck or taller pistons and your caming it up with a higher stalll and gears to match, the 360 heads will do a better job than ported 318 heads. But ya better be willing to run this pup due to the huge port window and cc amount the 360 head has.
Look at this way as well. If a stock X head can get a medium weight car into the mid 12's easy, with zero porting, don't you think that is a bit much for an engine down 20+ cubes in bore alone?
Why did MoPar offer a ported 318 head over a 360 head? Hummm, They did state right up front in the catolog that there ported 318 head made 55 more HP than the 360 head.
The real question is not will it work, but, will it work well and what is a better path to take?