Birmal and Dunn Heads
 

Is there a difference in air flow rate between left Dunn and Right Birmal Heads on a 95'?

Re: Birmal and Dunn Heads
 

Cliff,

IIRC, there likely is some slight differences as result of (reported) improved port matching and some other minor internal dimensions. Sources I've read claim as much as 20 hp improvement over the Birmal heads, yet the expense of re-certifying the HP was prohibitive in light of the fact the motor was to be discontinued. So! The "minor" HP change was never published. And, according to HOTB, some motors left MM with one of each heads - as you apparently have??

However, as you know, with only minor porting any flow differences are erased, FWIW.

P.