Totally depends on what you need or want from it. Rebuild kits can be found cheap and if you do the work the cost is not too bad really. Even swapping in a 0411 for better tuning without a full LS swap is worth it.
If you want 400+hp then look at the LS swap for reliability, easy of modding and tuning. But be ready to spend more on parts.
I have been debating this for a long time and think I'm gonna rebuild a extra 5.7 vortec, toss in a 395 cam, full exhaust and 0411 pcm. It will be a daily driver and sometimes towing. Don't need gobs of power and parts for the vortec are alot cheaper than LS parts. I'll wait to get back in LS stuff until I get another fbody.
"LS" parts can be had for cheap if you know where to look, like local U pull its for iron block 5.3 (LM7) or harder to find 6.0's (LQ4) all have these. Just make sure you get everything from the engine bay like an uncut harness, accessories, brackets, ecu. LS1's are indeed expensive but all parts are interchangeable, to the 5.3 & 6.0. Donor vehicles can be found for as little as less than $1k. A simple LS1 cam and LS1 valve springs (found used on eBay) upgrade really open up these iron blocks for like an extra 30 hp or so. If you want to spend a little more coin, you can have the heads ported too, and you will have well over 400hp. After alot of research I've done, the truck intakes have good flow and even the exhaust manifolds were well designed. When my buddy saw the 5.3 I was building on the engine stand, he is an old school Chevy guy btw, he was like dang, aluminum heads, the exhaust manifolds are like "Shortie headers" they did some good engineering with those motors.
Some people are terrified of the wiring but by doing it yourself, you can make a stand alone harness out of the original harness the engine came with. Reliability, fuel effciency, and tunability is definitely there. Good luck with whatever you chose. [emoji106] [emoji106] [emoji106]
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