[biketopia]

For what it's worth, if you are going with just a stock/mild build on your truck the factory stuff is fine, take an evening and look over the harness real good, but I would not be scared to run the stock harness to keep progress moving, you can always change things up down the road. If you want to get into tuning, and modifying etc, then I would 100% hands down go with the holley. If you are on facebook there are a few really good groups on there about the terminator/hp/dominator set up. And all of them will give you some really good recommendations on where to buy from, shops that install those systems every day and can 100% help with after the sale issues. It's not un heard of for people to be on the phone with Holley tech for over an hour on hold, so having a vendor that can walk you though any issues is huge. Deleting vats and rear 02's etc is something any competent mail order tuner can handle. Yes it's a few days down while you mail an ECU off, but if you are doing a stock set up, the holley is not being used anywhere near to it's potential, other than the self learning and then YOU have the ability to tinker with the tune. There's also plenty of local tuners that can tune with HPTunners, just gotta find em, again if you're not going for max effort then most anyone with a decent reputation in the community should be more than capable.

You said you ordered fuel line, from amazon. What did you order? I got some AN fittings from there in a pinch to save a few bucks on my Camaro build. Almost burnt up my 427SBC and left me on the side of the road multiple times because of crap fittings. They necked WAY down under -6, were sharp and damaged the inside of the hose causing a blockage and wreaking havoc on fuel pressure and causing me to go super lean.

My brother used to build hotrods for a living and he's told me numerous times through my few builds, sit down and write out your goals for the truck. Think about it, for a few days if needed, do you want a cruiser, a show truck, all out power, corner carver, daily driver. Then you can tailor your parts search and questions towards those goals, stock 300+hp and fuel injection goes down the road quite nicely with no need for headers or a cam swap, but if you want some lope a summit low lift truck cam can give you that for not a lot of money, but then it can snow ball into "well if I'm doing this, I should do that". If you are getting a motor with VVT or DOD, me personally, I would budget in a cam swap with new lifters and trays. Without knowing the maintenance history of the engine, poor Air filter and oil change habits are horrible to the dod lifters. When they fail you have a dead hole, hopefully they just collapse, and not lock up the roller and send a bunch of metal though the motor.

All in all you've gotten some really good advise and seem to have a grasp on what you are doing. Don't be scared to do it yourself, even a single guy with no family isn't going to build a truck in a weekend, get the family into it, car shows, cruise ins, swap meets, bench racing, busting nuts and bolts lose it helps. I'd also check out LS1Tech, TONS of info on the ls engines, swaps, upgrades, tuning, diagnosis, etc. It has it's up and downs of traffic but the OG guys that are still over there are more than willing to help out.