I'm Gettin off topic here, this could be moved if someone wants to move it.I bought a 10 mil Cub complete a couple months ago (Supposedly built by RDZ and make 124 hp, but I didn't for a second believe that it would make that hp....and it didn't) I tried BB CPI and RDZs on the dyno. Didn't bring any Shearers to try. (I have tons of sets hanging on the wall as well.) The RDZs had a surpisingly broad curve at the top, but the CPIS made 3 more peak hp, and more hp from the bottom up. This Cub had 200 or more degrees of exhaust duration, so this won't apply to every 10 mil Cub. Tried some SB silenced CPIs (all of the packing was missing) and it held so much heat, it only made 1 or 2 pulls and was down about 9 hp; BUT I didn't do much tuning because I already had it dialed in with the BBs and didn't want to change it (i.e. lazy.)
I tried back to back runs with BB and SB Shearers on my other 10 Mil Cub which had much lower exhaust duration. Maybe as low as 194*, I don't remember. There was no difference in e.t. 3.89 on both passes.
I'll be dynoing what I believe to be a very good running 392 Cub (should run low 3.8s or 3.7s with a Jockey) very soon and try to compare RDZ, Shearer SB, Shearer BB, CPI BB, and CPI SB if I have time. Trying to get this one competitive for 0-400 cc in Gilbert this year.