aldang25879
I'm Awesome
Not to be the “my uncle” guy, but My uncle has a boosted 4.8 on 4.10 gears and drag radials and he whooped a lot of people with it. I can ask but as far as I know he only raced other LS guys not any 350’s. Most OBS guys around here are low riding cruisers. only recently he lost one, he kept up (slightly behind) with a c6 vette until 75-80 mph. It still threw me in the back of the seat though and had me impressed. I agree that he really lost power compared to the vette, when he got stuck in a higher gear and couldn’t get to his higher rpm. But it’s definitely more power than I would be able to handle.I will put it this way. My stock L31 350 fullsize conversion van never lost to any of my friends 5.3L trucks or SUVs. With headers and a tune it ran next to a Vortec Max 6.0L extended cab short bed to 80 mph.
400-500 hp and still no torque. As I said all revs and no pull. The kind of cam you would need to get 500 hp out a 5.3L would never run well in a truck and 600 hp is a pipe dream. That would be a 10,000 build or more to make 600 hp from a NA 5.3L. Do you have any experience with a boosted 4.8L? Even with boost they are an absolute dog until 4,000 rpm. A 5.3L with a stock camshaft needs a converter like a Yank 3,600 rpm and deep rear gears to get a heavy truck rolling well. The stock 5.3L I personally setup had a Yank 3,600 converter, a 4.30 gear and a 28" tall drag radial. It ran fairly well but it was not overly impressive. I think it ran 8.70s in a regular cab shortbed from memory. Before the converter and gears it was mid-high 9 second truck in the 1/8 mile. It ended up a 1/2 second quicker than a 1999 Suburban on street tires, with S10 converter, long tubes, volant intake and a tune. Suburban was nearly 600 lbs heavier and ran 9.20s with L31 power. I will choose a Vortec 350 over the smaller LS engines anyday of the week. The LS is marginally stronger in stock form to boost, but not as much as some would lead you to believe. Stock L31 bottom can still handle 700+ hp as reliably as the LS can. Both are a ticking time bomb much over 500 hp on stock internals though. The Gen III just do not hold up in the real world for very long beyond that.
I’m not a genius nor do I claim to be one. I have limited experience. Do you suggest building the top end of a 350 vortec and keeping the bottom end stock? How much power can that produce? What about a supercharger? That would be one Roudy truck. If it’ll whoop my uncles’ then I don’t see why it’s not a valid option.
For context I’ve only had racing experience with 4.8’s and 5.3’s. I have the 5.7 vortec and it’s damn sluggish but, if a rebuild will produce better results, engine swapping suddenly seems unreasonable.