swap from v6 to v8
 

I have a 98 gmc jimmy 4x4 has the v6. Im goin to swap to sbc 350 5.3 vortec. Should i get same year motor? And also jegs sells a kit to swap has anyone purchased kit and was everything in there needed for the swap? Thanks for any info

Are you wanting SBC or LS platform engine?
You state SBC 350 but also 5.3 vortec. 5.3 is a 325 LS family engine.

How do you want the swap to work? Are going for the cheapest route, or do you want stuff like the factory gauges to work? are you wanting to keep the fuel injection or go carb?
For the simplest swap, I would look into a SBC based 350 engine with the factory CPI spider injection like the blazer already has. This way you can use most of the s10 harness, sensors and all you will need is engine mounts, headers, oil pan, and electric fans. this is because the 4.3 is basically a 5.7 with cylinders missing.
One of the most difficult things for the 4x4 is oil pan clearance with the front differential. but everything else is fairly simple.