I'm thinking along the same lines as Jerry, something is lugging the car down and it is working too hard to overcome that drag. You say you have a 5 speed, what gear ratio in the back? The point I am trying to make is that if you have ever driven a stickshift where you didn't downshift far enough making a turn it will act like what you are describing or even buck. A hot cam will accentuate that even more. In my 27, even with 4:30's and in low gear, it bucks going through parking lots sometimes because of the somewhat radical cam. You could be experiencing something similar.

Don