StageV Engineering made HEMI conversion heads for B/RB's, NRE was just on this site what,..a month & a half ago talking about the Predator heads..like 470cfm ootb & mid 500's well ported, plus NRE had the Covalt 32V conversion for $10K in the 90's..the whole kit intake, heads, valve covers, pushrods, all You had to furnish was a HEMI pattern cam & headers....crickets. The only heads that went anywhere were the B1's, mainly due to Alderman/Geffrion's seasons running them, the publicity & wins sold them.
The Covalt setup made low 800'sHp w/a freaking 280° cam,....no takers, everybody skeert....it's amazing anybody builds B/RB Mopar stuff today.