Hey everybody, I'm new to this game and just got a 79 Chevy K-5 Blazer. It's got a 350SB, SM465, NP205 and is on 33" BFG ATs. Everything is fine when I shift into 4Hi, N, 2Hi and 4Lo, but the trouble is getting out of 4Lo. It takes about 10 minutes of rolling back and forth to try and knock that thing back into any other gear. If this is normal then I'll learn to live with it, if not then are there any suggestions on a fix? Thanks.  

Sounds like you have some torque bind that it causing it to not what to shift. Place on axle in some gravel or grass before you try to shift it and change direction briefly after you first stop too. Also consider than if you have like 3.07 or 3.42 gears or even 3.73 to some extent that they place a lot more torque load and bid on Tcase than deeper axle gears do because less drive shaft torque is required before wheel slippage is encountered.  

I have 4.11 gears with a limited slip in the rear. I'll try the direction change on the grass though. Thanks.  

GentlemanJack:
I have 4.11 gears with a limited slip in the rear. I'll try the direction change on the grass though. Thanks.

Yes try relieving torque bind and also change lube in Tcase if you have not done it for a while (80w90). BTW, for what it is worth, 4.10 with 35's is about equal to stock tires and 3.42's which is not deep.