Have a truck with 410. Rear end and 400 tran. But gas is killing me .Have a 700-r 4 tran. That i could put in Or change rear end have a set of 342 .??

 

well if you change tranny you will have to change yoke on drive shaft and possibly shorten it as well , move the cross member, and have to get a tc lockup switch, and i'm not sure which flywheel you will need. if you dont pull anything then id go for the axle swap if you do pull id say change trans having the over drive will drop your rpm +/-500 when fully locked up thats my .02