will a 73 chevy 5.7l 400 engine bolt up to a 89 chevy 350 hydromatic trans

400s are externally balanced /350s ate internally balanced .you will need to use the 400s flywheel and harmonic balancer. Problem is I believe the 89 is serpentine belted and the older 400 banacer is V belt .so you will have to buy a conversion pulley for the balancer aND sone tinker ing on the accesores i.e. alt,pwr string ,A/C eTC . You will also have to change exhaust manifolds I'm 90% sure they will be the wrong ports . Other than that shiuld work out fine.as far as bell housing bolts ,engine mounts etc. Good luck