Dodge 318

I have 2 slants, one an auto and the other a manual. I have several V8's as well. I did a 5.9L swap into my 72 Charger. IMO I would keep the slant 6. Everybody has a V8 these days, how many people still have the slant 6. The slant is a fast peppy motor when it's running right. My slants will go head to head with any V8 all day long.
Just my $0.02