OK, just to be clear, I'm not having any lockup issues since I upgraded to front disc/rear larger drums. And, again, from reading the feedback above, it is clear to me that I don't need rear discs. On the separate issue, I think a vacuum reservoir can would be helpful during frequent braking. I don't see any issues on occasional braking, but when in traffic on frequent braking, the idle is affected somewhat when I brake. Seems like a buffer tank would alleviate this issue. I'll wait until I do the engine swap, it may be different with the new engine. In that light, question, generally speaking, does a street cam or a performance cam create more vacuum at idle? This new engine will be more on the performance side.