Timing?

i have a 95 nissan 240sx with the ka24de with around 5000 miles on rebuilt motor which has cp pistons and eagle rods ect., it spun a bearing so i replace the rod bearings and main bearings, then put everything back together set the crank to tdc and set the distributor to spark plug #1 and fired it up then set the idle to around 700rpms. everything sounded good but once i put it in 1st to take off it became very sluggish rpms very slow and it hardly moved once i hit 20mph it stayed the like it hit a governer or something. could the be the timing or am i missing something. thanks in advanced