Jeff is right. In Texas you are going to dig a deep hole for yourself if you try to move the VIN from the S-10 vehicle to what most will still consider a 54 truck, including TxDOT. Take what you want from the S-10 and when your finished, sell or or give what's left of the S-10 to a wrecking yard WITH the title to the S-10. Your 54 - 5 window will remain a 54 - 5 window. If you ever sell it, just tell the buyer it has an S-10 frame under it. That's it!
Joe
