As far as most HP I think I would be a cam. Now if you just want to drop off time then I would say a set of gears (If you can get them with a posi that would be the best), a stall converter or a set drag radials if you already have a posi. I got a stock LS1 in my 91 but I get no traction whatsoever, Im getting a posi with 4.10s the minute I get back to the US. That should drop at least half a second off the 1/4 mile.