Help me decide... 383 or LSx?

[df2x4]

I thought you were supposed to worry when a GM product stops leaking, that means there's nothing left in it. Maybe I was thinking of Harley Davidson...

My '97s (5.7 and 4.3) both drip a tiny bit of oil. It's never been enough to read low on the dipstick though, and I regularly go a year or more between oil changes. Pretty sure I've found all the sources and it's all relatively easy stuff, I even bought the parts to fix it all on the Suburban. Just hasn't bothered me enough to fix it yet.

My dad has an '06 3500 with the LQ4 6.0 (with nearly 300K miles) and it's the exact same way. I think either an SBC or LS platform should seal up pretty tight as long as it's taken care of.

 

[Tachyon]

I think your last line says it all. Budget "I'd like to try and stay under $6000"

Unless you go full on junkyard commando, Driveway Engineer (YouTube guy) and get everything used and do all the work yourself, you'll be hard pressed to get an LS swap done for under $6k. Plus it'll take you probably months at a minimum to have a vehicle you can trust to drive regularly. That's because there will be 1001 little things you didn't plan on and couldn't account for that you'll have to take care of.

Granted, if I won the Lotto tomorrow, I'd be working on an LS swap the day after that. But only because I can hire out most of the work and throw money at the problems.

The 383 swap on the other hand is essentially painless and can be done very inexpensively. I know because I've done it. Check my sig.
I don't see what year your truck is mentioned in the OP, but if it's a late model with port injection and you haven't done the CSFI to MPFI conversion, do it!!

In my case I bought the whole core 383 package which meant I got a 4 bolt main, forged crank, roller lifters and "RV" cam, hypereutectic pistons, and other parts that I would have wanted anyway because I my case I was as much interested in increased durability as I was a power increase. In your case I'd recommend the same. At least get a 4 bolt block and upgraded, matching crank, rods, and pistons. A really should do is add a decent cam that boosts low end torque and gives a little power too. You'll definitely need to increase breathing so a cold air intake and headers with a good exhaust are a must. Finally you need to custom tune the PCM or most of this is wasted. If you're going to do an 0411 upgrade, now you're starting to push the complexity to the point where you might as well start considering the LS swap.
Anyway, back to the 383. A quality built 383 with the right components can be powerful, rugged, and reliable and is IMO still the best street SBC for big cars and trucks. They can make power with the best of the 5.3l LS's for a lot less work.

Having been in this position and having faced the same choices, I wish you luck. It's not an easy decision. We're lucky to have a platform with so many good options. Whatever you do, PLEASE post it and all the things you faced along the way so everyone else can benefit from your experience.

Personally I've never regretted my 383 upgrade for a minute. I've only ever regretted not having the money to do more and better things to it.
Like move to an aftermarket EFI system and bigger cam.

 

[AK49BWL]

MPFI, Headers, 0411 swap already done years ago (heck I bought it with the headers lol), been custom tuning it myself using HPTuners since 2017. The truck is my 97 ECSB Sierra, nearly everything I've done to it is listed in its project thread in my sig the only thing I don't know is whether it's a 2 or 4 bolt main, but I'd have to guess 2 based on the truck being a light duty 1500.

 

[L31MaxExpress]

Only place my L31 ever leaked was the crappy plastic timing cover and oil line quick connects. Doubt I will ever see it leak there again with the Holley aluminum cover and AN oil cooler lines on my 383. Have about 1,500 miles and it is all dry.

 

[Tachyon]

Yeah, I felt bad replacing my L31. It had over 330,000km on it and still ran great. I put off the 383 upgrade until I found it a good home. AFAIK it's still running fine in a buddy's old Chevelle. He dropped it straight in, just added an Edlebrock Vortec manifold and a Holley carb.

 

[97silveradoguy]

My 96 350 Vortec doesn't leak or burn a drop of anything, and has plenty of power when I kick it in the ass.

 

[HotWheelsBurban]

My 96 350 Vortec doesn't leak or burn a drop of anything, and has plenty of power when I kick it in the ass.

How many miles, and are they city or highway?

 

[90halfton]

Do you like high end or low end power? I have drove a 2500 6.0 as a work truck for years. Took a long time to not hate the high end power, but they're reliable light duty workhorses. I get in my 5.7 tbi personal truck and it feels stronger at low rpms. Trailer or not. In dirt bike terms, going from a obs to a nbs is like getting off a 4stroke and getting on a 2 stroke. Both great, but different feel.

 

[AK49BWL]

I'm definitely more a fan of the lower rpm power. Maybe that's what I can't get over when it comes to driving my dad's trucks lol... They just don't have it.

 

[97silveradoguy]

How many miles, and are they city or highway?

It's got 164,000 miles on it. It was garaged from November to April by the previous owner. It was serviced religiously. The owners manual pouch is stuffed with service receipts. I drive locally mostly.