Does any one out there know where the transmission fluid drain plug is on a 3 speed th350 transmission, or if it even has one? Any advice yould be appreciated.  

there isn't one, the best way i found is to loosen all cap screws, leave the four corner screws in and take the rest of the cap screws out. put a drain pan under one end
and carefully take the two screws out and lower pan to drain fluid. when fluid is low enough take the other two screws out and procede as normal to change filter and gasket.  

Thanks man, i really appreciate it.  

Any way, Im new to this internet forum thing,
Another question---one else know what king of oil (gear oil maybe?) to use in a NP203 tranfser case?  And what the shift pattern is on the said case.  It has the floor shift.  

USE 10W40 MOTOR OIL, REG 90W GEAR OIL IS TOO THICK TO LUBRICATE THE CHAIN/TRANNY FLUID IS TOO THIN AND WILL NOT PROPERLY LUBE THE BALL BEARINGS...AND I BELIEVE THE SHIFT PATTERN IS 4HI(BACK TO SEAT),NUETRAL,4LO,2HI.
SO HOPE THAT HELPS...YOU CAN MAKE THE 203 LAST A LONG TIME W/THE PROPER LUBRICATION

ROCK ON!!!  

Dang man! What are you a transmission guru or something? You wouldnt know of any websites where you can type in the VIN and serial numbers off of an engine block and get its specs (year made, factory location, number of splines, ect. that sort of thing)  The one in my truck a carberated Chevy 350 LT-1 iron block origonally out of a 1990 something year model corvette.  
Thanks again.  

*****non detergent oil..........the 203 is full time hl-h-n-l-ll.

some 350's do have a drain plug, they are a rare find. the pan needs to come off anyhow to change the filter  

I FOUND THAT LMC.COM WILL BREAK YOU VIN# ON YOUR P-UP,TELL YOU WHERE IT WAS MADE AND WHAT THE DIDGETS OF THE VIN MEAN, ALSO THE CAST # ON THE BACK SIDE OF THE BLOCK OR THE STAMPED # ON THE SHELF RIGHT BELOW THE PASS FRT OF ENGINE SHOULD BE FOUND IN CHEVY ENGINE REBUILD BOOKS..OR YOU MIGHT BE ABLE TO TAKE THE #S FROM THE BLOCK TO YOU LOCAL CHEVY DEALER PREFERABLY ONE THAT SELLS PERFORMANCE PARTS AND THEY CAN DECIFER THE #S FOR YOU  

OH AND NO IM NOT A TRANNY GURU...BUT I DID STAY AT A HOLLIDAY INN ONCE!!  LOL!

ROCK ON!!!  

Friggin' Hilarious.  Once again thanks.  

Oh yeah, Im planning on putting some sort of locking rear diffrential in my truck (1980 K-10 pickup) I was looking at a Lock Right Automatic positive diff from Jegs for about $300.  I dont want to weld up the spiders, because this is my only vehicle and it will be driven on both street and off road (too much tire wear on pavement)  Any yall have any reccomendations or advice?  

you know i was looking at that too, sounds pretty good if your not runnig BIG tires. and it should work great if your not constantly climbing rocks and work great just doing light off roading  

Define BIG tires,  i got 35'' superswampers right now  

a selectable or air lockr is on call for 35's.....over 33's  

37"-44" ive seen that big on 6" w/3" body lift