what size tube or pipe works best for sleeving the stock front driveshaft to lengthen it?

cut a spare in half, take it to the metal shop and find one that's a snug fit, that way you're sure.

2" ID mechanical tube. grind the paint/rust off the driveshaft and hammer it in snug. I lengthened mine with this method and can drive it @100km/h with no vibes

2" ID mechanical tube. grind the paint/rust off the driveshaft and hammer it in snug. I lengthened mine with this method and can drive it @100km/h with no vibes
not to sound like a dumb ass but what is mechanical tube ? i have to do the same thing

mechanical tube is schedule 40