I believe stock Mag pushrods will work with your earlier 318 roller cam setup.

There are a few ways to go on the intakes and the first way is to use one of the Chinese copy intakes that are not too expensive and have holes for both configurations. The second is to redrill the holes in the head using some sort of a jig. You'd fabricate this yourself, setting it up on a LA head and welding it up. The jig that was around several years ago is no more so it is out of the picture. But it was homemade in much the same way. You need a tube at the right angle to aim the drill bit.
The third is to use the LA intake, elongate the holes, and make some angle spacers for the angle between bolt head and intake surface.

I'm a big EFI fan too but IMHO it's important to get this project on the street. Trying to add factory EFI could take another year and by then the project dies.

R.