340 Cam Kits which ones work with a stock block

Don't get me wrong, before I put the new tires on I could easily spin the tires in second gear and a little in third. Since I put my new tires on 245/60/15's I haven't been out with the car because the weather here has been horrible plus I need to take it easy for awhile as I'm breaking in a new set of gears. Time will tell. There is one other way to tell on the TC, 10 mph roll in 3rd gear and punch it, tack will spike to a rpm and hold for a second have to do it a couple of times for an average. Not the greatest way but the best we can do. Tomorrow will tell
Was that with the 3.91s already?