Not exactly correct on the above B numbers, at least not according to what I have from Joe years ago. DWR-46: Please no offense to this. None of my post are meant to offend anyone. I only hope to figure out some of this great history and it would seem like there is a lot of crazy info floating around.
DWR-46 I did enjoy your post on trying to correct folks on the Bonneville Record Breaker video. I noticed that the car that they used mostly in the video had no roll bar and had emblems on it, the prototype that became the Due Cento did not have any of those. There are a few shots in the video that are the actual car.
B-7 was an R-4 that was in the #7 Hawk
B-8 was not an R-4, it was an R-3 that went to the engineering department
B-9 was also an R-3, the Lark convertible #3 had R-4 B-28, dual valve springs, and a 275 camshaft.