Direct Connection ( Mullen LA ) heads

I would think 1.5 hp/cubic inch would be within reach with 13:1 and 110 octane. It's really dependent on how much V.E. the heads will be capable of through the full house RPM manifold. Historically, though, the heads are really a neat piece. The experimentation and lessons learned from those heads are what led to the W2 platform. An overall head design that is still more than adequate for a lot of purpose built race cars today.