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Nnbs 5.3L Upgrade

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I know this isn't about a Silverado SS. I just sold my SS a few weeks ago, had purchased a 2007 NNBS black crew cab GMC in August, mint shape, fully loaded, but 248,000kms. The lady had the oil changed the day before I picked it up. I have put roughly 4000km on it since I bought it. Today I went to our other yard to look for some snowmobile parts. My DIC center told me to check engine oil and add engine oil. I thought that was funny, got back and checked it and its barely touching the dipstick. I had checked it before I bought it and it was indeed full. Looked under the truck and it isn't/hasnt leaked out.


So my question is, what direction should I go. I have an early 6.0L longblock I bought a few months ago for a couple hundred bucks. My plan was to build a 408 and stick it in my NNBS, or into my 70 GTO. I haven't pulled it apart so I am not 100% the block is good. Guy told me it had started burning oil. Obviously I have to dig into it deeper to verify it can be used, has no cracks etc.


First option. I can buy an 2003 LQ9 with around 120,000km and use my NNBS intake and drop that in my truck. Will cost me $1200-1500 for the motor, not positive on price yet. Or, get my 6.0L apart and start ordering crank, rods, pistons for a 408 and have the machine work done. Am I able to use the 243 heads that are on my 5.3, or use the 317's that are on my 6.0L I have in the shop if I went 408? Can also pick up a 6.0L from a 2007+ truck, L76 motor for $1750, it has 126,000km on it. These used motors are from the salvage department of Saskatchewans only insurance company. Motors are out of wrecked vehicles.


I was just about to order a 6" lift and 35" rubber for my truck. Guess that won't be happening. I need to be able to drive before I lift it haha.


I miss the power of the SS, this is a much heavier truck so the more hp I have the better (450hp would be amazing eventually). Won't be at the track, if I did go it would be like once or twice a year. I will be pulling a 5000+lb trailer once in a while. Don't really have a max budget, I'm Ukrainian and like to save my money, so the less I spend the better. Probably able to throw $3000 right now at building a 408 if that is what the best option would be. Could just do a factory 6.0L and throw and cam and maybe even ported heads at it.


What direction would you go?

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Hard to say which way would be the best for ya...


The best thing I feel is to tear one apart and refresh it. then drop it in your NNBS, I'd go with the build, the 408. That way you know what you got going on, any salvage motor may have problems and your just gotta inherit those problems.




Side note, don't know what motor you got in your Goat, but if its a 400 or 455 keep it, a original GTO is a lot more beautiful at a car show and driving than a butchered one. That's my opinion thou...

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