As Pipeman suggested, go back to parts store and get the old nose from orig starter and swap it on to the new one.
If starter is not shimmed properly, One of two things well happen:
1. Shimmed too far out, rip off ring gear teeth and create a high pitched whine when cranking, well also destroy starter pinion. Place shims under outer bolt to shim starter towards ring gear.
2. Shimmed too close, starter may jam in place and run continuously until battery cable is pulled from battery. Shimmed alittle less close, starter will be in a bind, therefore requiring more amperage to turn over, thus heating up battery internals and I have seen abattery melt its plates together and becomes a door stop, a good one if it has a handle on it. Shim both bolts the same thickness to place starter away from ring gear.
Usually a starter will demand no more than 150 amps. Have a VAT-40 machine check done, Sears has it. This will check out starter system, charging system, and battery capability to supply both.