Have not started yet. Mark moved his shop this winter and he still has all of my bolt-ons, so he will probably build it but has not had time yet. I spoke to a few builders in San Diego and they thought I should go with a 540 instead of a 502. My blower is only a B&M 250 so that might not handle a 540's needs. I have gotten different opinions on this topic. 502 or 540, both should bolt up to everything else just fine. What a dilemma.