hi there. i installed the A cam and redrilled gear 6 degrees advanced in my sons 87 245 also i removed one muffler and i have a free flowing cat. its a little loud not much, and after you reach crusing speed the noise level is quiet. i didnt measure any times or anything but i have a 86 244 with the m cam and 85 244 also and can tell the difference for sure. from 60 mph to 75 mph the A cam makes a very noticeable difference for what were working with. like you said it doesnt take long to swap. and if you like it you can ebay the vx cam. i have read over on turbobricks web site about the vx cam and people dont like it much. do you think your cat is good? the vx should have made a difference. i was thinking about the turbo cam from ipd, for my 85 244turbo but im skeptical. i also have the K cam which is supposed to be good for very high rpms but its on my shelf. i believe i have a address for the person i purchased the k cams from. im no expert for sure this is just my experience.