Swapped to 528 mech cam slowed down

Well, the lash is "fogured in", but they dont add lift for it. It's just part of the design phase. The tight lash have a different ramp shape to deal with the less lash. I run my big block .528 solid at .018 int and .022 exh, because I hate the sound the recommended lash gives too. A tight lash cam runs about .004-.006 tighter than that in the cases I've seen. To me, if tightening the lash makes the car faster (assuming the 60'/traction deal wasnt occuring, I'd say you chose the wrong cam. Lash is not a power maker, it's a maintenance thing. Getting the right size cam is where the power is made. My .528s give up lower in the rpm range, but a lot of that is the heads. Truthfully, a small block .528 will lose more thru pushrod angles than a big block anyway. So really, minus lash and loss from angles, you're looking at a .490ish cam. That might rev real well in worked heads, but may not go as high on stock castings in some packages. The Comp 305 is soft on the low end, and limited by lifter type on the high end. The MP will be much stronger down low and mid range, and may not have the pulling power. So it's just a "rethink the package" deal. Honestly, if you can't stick the tires with a torquey cam in it now, you have extra time until the 418 is done to figure out how to stick it.