Two piece front drive shaft

The drive shaft that came with my truck is about 3 in Long then it should be, it came with the automatic transmission from the factory, my brother put a standard transmission in and now the front two piece is too long, I've been looking for a replacement but I can't find one the exact length of measure, some are two or three inches too long some are two or three inches too short,
My question is if I got one that was two and a half inches too short but it had room to be extended from the yolk would it be safe to do so? Where the two piece attaches together the spline and the inner, I'm just wondering how much room this thing can be extended and if it's okay, how much of the spline can be exposed.

@Ricko1966 .

Don't do it,get your long shaft shortened. I'd be worried at full extension the driveshaft will come apart,also if the splines aren't in deep enough your going to have a vibration,and last but not least the splines won't live long.

Splines should not be exposed on a driveshaft.

Based on parts from RockAuto, you need a 23 7/8” drive shaft, and your old one is probably 29 1/2”, measured from center of one u-joint to center of other u-joint.

A new one for MT is about $400, so finding a shop to shorten yours is probably a lot cheaper. Also budget for new u-joints, since you have ir off and they are easy to replace.

Id put a Auto trans back in it