345 to D414 swap

Anyone know what it would take to replace a 345 engine in an old '63 IH B180 truck with either a D414, DT414, or DT 436 would take?  Drop in replacement or big pain in the rear?Thanks.

The head mechanic at our now closed IH dealer did a similar switch on a Loadstar maybe 20 years ago. My memory is pretty sketchy, but here is what I recall. The engine compartment in the Loadstar is pretty short, having been made for the 304/345 V8. The distance from the radiator to firewall is less than needed for the longer 6 cylinder diesel engine. I think he moved the radiator forward and modified the grill to accomodate. The longer block and oil pan fit between the frame rails and cross pieces, but he gained the extra length for the now more foreward fan to clear the radiator. I can't recall the reason, but he had to lean the diesel over about 20 degrees to clear steering or suspension members. Then custom built motor mounts. With the engine leaned over, but the tranny needing to be upright, he may have fabricated an adapter plate at the bellhousing. Then the rear axle gearing is wrong for the diesel. The diesel likes to put out its power in the 1900-2300 RPM range, while the V8 pulls hard up to about 3600 RPM.

Bottom line: he said that he'd never do that switch again, it was an interesting piece of work, but not a very good truck. I respect his efforts and craftsmanship.

Paul in MN

Thanks for the reply. That's exactly what I needed to know, but not exactly what I wanted to hear.