OldIHC

Would like to convert from factory 4 spd. The 1510's kind of a cross between the 1310 1ton and a 1600 loadstar. Just wondering if perhaps a loadstar transmission would fit or if input shaft is different. Thanks - Bill.

There is no such thing as a "Loadstar transmission".
Transmissions are identified in a few different ways:
IHC Code - 13427
IHC Model Number - T-427
Mfr Model Number - T-19
Those are all designations for the same transmission.

A 5-speed transmission as used by IH in their light line trucks will fit and were factory installed in the IH Pickup trucks & Travelalls. The input shaft is larger in diameter, therefore is uses a different pilot bearing.
It is a larger transmission and therefore uses a different bell housing than the 4-speed units.
It typically uses a different flywheel in the Loadstar to accommodate either a 12" or 13" clutch.
In the light line trucks, it typically utilizes an 11" clutch, due to the much lower vehicle GVW.

So, to swap from a 4-speed to a 5-speed you will need to do some additional work than a simple trans swap might indicate.

You would need to properly identify any donor transmission prior to starting your swap to be sure your transmission was the correct unit.

Well that's what I was wondering. Thank you for the reply.