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