[83GMCK2500]

If you're using the filter that mounts to the intake I'd say an o-ring kit and larger fittings in the 6.5 FFM: http://walkingjdesigns.myshopify.com...feed-the-beast

Forum write-up on 6.5 FFM upgrades: http://www.thetruckstop.us/forum/thr...uel-to-ip.572/

You can actually upgrade to the nice big Donaldson filter and mount that the Duramaxes use, my Dad put one on his '87 V1500 w/6.2 + Banks. If you're not familiar with it, the filter has a water-in-fuel sensor on the bottom that will wire into the squarebody circuit. Bonus features include a priming button on the filter mount.

6.5 glowplug harness is prone to wearing out over time, not saying you need to buy this, you or someone you may know might have the sparky skillz to make one yourself: http://ptwiringsolutions.com/t/glow-plus-harnesses

If I remember correctly the factory 6.5 fuel system includes a lift pump which is a good unit and often added to 6.2s. Alternatively there are some nice relay kits with Walbro pumps here: http://leroydiesel.com/product-category/fuel-delivery/ <---really, all of that guy's stuff is pretty nice with quite a bit of research put into it. I follow that TTS forum that I linked above and that's where I found his stuff.