Advise your buddy to find a good header builder regardless of which way he goes, all the commercially available models leave much to be desired.

Fenderwell exit is pretty much the only option with the torsion bars in place.

I've got two examples of BB early A's near me, one a 65 Valiant, the other a 64 Valiant, and both cars worked extremely well.

Unfortunately, my 62 has even less room (at the firewall) so I'm forced to run a small block, or cut it up more than I'd like.

Don't let these guys fool you, a stroker small block will not fill that BB jonesin' we all get!

I know from 1st hand experience. My little 428 will run all day on pump gas, drive to the track and lay down mid 10's uncorked, then run 9's with a touch of nitrous. It has torque for days, and will slide you back in the seat regardless of what gear you punch it on the street! Give me an instant smile every time I lean on it.

But then you get back to the pits after whipping some rat, and pop the hood, and everyone walks over and say's, "It's only a small block?"
Then you have apologize and say, "Yeah, I wish it was a big block too, but this was all that would fit!"