454 swap motor with th400

[chastain90]

I have the sm465 right now and am building a 454 for my blazer. If I put a th400 in place of my 465 would I be able to slide the motor mounts forward to counter act the clearance issues? I cannot find anything on how much longer a th400 is than a sm465 and do not have one available to measure. But I was thinking if this would work out to my advantage would my np205 tcase bolt to it or would I need another one? And would the front driveshaft have to be cut or lengthened?
thanks for any help.