346 vs 906 heads for porting

[Robe 1963]

I believe I 'll go for a home porting job on heads..
Doing a ligth porting with templates I guess 906s are better,but in case of a major job,as explained some time ago by Mopar Muscle,could I get the same benefits
from the '73 346? At least should I make a mistake ,I
woudn't ruin the original 1970 equipment..some advice
is welcomed,thanks

[ehostler]

Go with the 452's. They already have hardened valve seats, that work with unleaded gas. There are also a large number of these available. The 452's will also out flow the 906's.

[Fury Boy]

I would use 906s but in your case use the 346s, they will work with unleaded gas because they have semi hardened exhuast seats(if they are true'73 heads they will, '72s and '1s probably won't)

[Chargerchuck]

While the 452 heads are truely hardend, the '72 heads are partially hardened and work fine with unleaded pump. The '71 346 heads are not partially hardened and would require some work if you are running it on the street.