to help with picking a turbo, use this link.
http://www.treadstoneperformance.com/techinfo.phtml . click on the turbo matrix. wait a while for it to load.
on the left pick your motor size.
at the top pick the hp you expect to make.
intersect the lines and you will see the turbo that turbonetics recommends.
for instance on my 292 i have a 62-1 w/P trim and a .68 tangetial housing. the compressor has potential for up to around 600hp. the turbo spools nice and quick and produces 10 psi easily. a 250 would possibly need a 60-1 and the coresponding wheel and housing from the chart. for a 250 with a shorter deck than a 292 than i would also recomend a "on center housing" to place the turbo higher on the engine for frame clearance. tom