All the big 6, M30 engines will bolt up, they are the same block externally, so 3.5 is a go. They will work with your 4-speed or you can get a E-12 5-speed using a different driveshaft. Later 5-speeds will bolt up but do not have a speedometer drive as they used electronic speedo's off the differential. But be advised that many 3.3 and all 3.5 US spec engines are motronic and need a different cam to work with your distributor. Mike W.