I've been researching the camshaft mod for my lovely little volvo 86 740 gle NA M46 with 200,000 miles. So, I'm a crazy high school student, therefore I want to go for the craziest mod to go along with my _nice_ muffler. I've only seen the k-cams on ebay for the past few months that I've been watching. Has anyone seen the H cams there? I read they were only used in 1 year and only in Europe. Is the H too crazy, will it kill my baby? Also, how much will getting a machine shop to cut the distributor drive slot cost? Will they know how to cut it? Will my old cam be enough of a hint for them? I had a racing shop resurface my flywheel- I'm happy with them- they build racing engines.

Also of worry, when accelerating hard and I downshift to the next gear, say 2nd to 3rd i get a puff of dark colored smoke, i think it's black. That indicates to me that it's too much fuel. Fine I figure if I'm accelerating, right?
More worrisome is what happened today, I was accelerating in 2nd up to 49 or 50. Then I backed of totally of the gas and let the engine slow me down. In my rear view mirror I see this smoke that lasts longer than a puff. It went away after about 2-3 seconds as the rpm's got lower. Is this an indication of something serious I need to take care of before getting a more wild cam?

Thanks,
Nathan