So I have gotten the itch to do some vintage road racing. I have done a couple track days over the years but that is all. I would be building a KZ750 twin overbored to 906cc. After talking with a guy racing one in Canada I think I can get the weight down to 350lbs with 80-85HP. The classes I would be looking at would be WERA Vintage 4, or ARHMA Superbike - heavyweight.
Right now I'm leaning more towards WERA because it seems like the class rules are a little more lax, and this bike might be competitive in that class. In the ARHMA heavyweight class I would be significantly outgunned on power because I would be racing with the KZ1000 and other big 4s. Also a big part of the ARHMA superbike class is to preserve the look of the era. which they are pretty strict on. I understand the desire for that, but that is less appealing to me.
ahrma or wera, depends on where you live and if you like to travel. for me there is only one ahrma event within 10 hours, wera raced vintage at 3 tracks(4 events) within 6hours, so for me it was wera. wera was a back up plan for me. with the border closed vrra was out, . if your in new england uscra.