Wanting to know more about 383s

[Kyle89]

So I been rebuilding my 92 k1500 nv4500 silverado everything from the flywheel back is new but the u joints. I been looking around for engine upgrades, and I've been kicking around the idea of having my mechanic( not a shade tree mechanic) build me a carb 383 out of my 350 block. If I buy a crate motor with all name brand parts I'm looking at 4500 to 6500 for a 383 with 350 hp smooth idle and 420lbs torque cast iron heads and small valves. Now if I have my mechanic build one with my block adding aluminum heads, he can crack 500 hp and nearly 600 ftlbs of torque for 5k with a install. My truck has 373s and the first gen nv4500 lower low 1st and second. I plan on running 33s for quite a while before I lift it for 35s . I know 373s are a little tall gear for 35s but with my trans and that kind of power I should be fine . I do plan on upgrading the axels to 3/4 ton or one ton later on . He said with me having that trans and gear ratio it would move 35s with no problem but that's later on after I get a lift to fit 35s I can clear 33s stock no trimming or rubbing. And he said its street manners would be pretty decent because of the manual trans. So other than pricey and fuel mileage what are the pros and cons of a 383 daily? I am building this truck to have way more power than I will ever need but I would rather have it and not need it than need it and not have it.

 

[Schurkey]

500 hp, 600 ft/lbs is a pretty lofty goal for a carbed 383 that's in a heavy vehicle with big tires. I think your guy is dreaming.

 

[L31MaxExpress]

500 hp, 600 ft/lbs is a pretty lofty goal for a carbed 383 that's in a heavy vehicle with big tires. I think your guy is dreaming.

I am at about 485/485 out of a 9.6:1 350 with Lloyed Elliot ported 205cc Assault heads and a 215/225@ .050 cam. About to swap the Marine crossram intake for a dual plane. The HP seems possible but the torque estimate seems about 50-70 ft/lbs high. If it were a 396 or 406 it could get 550 TQ fairly easily.

 

[Schurkey]

...but what would it take to get 115 additional foot/lbs out of that thing? An iron lung? It's not going to happen with 33 cubic inches.

600 ft/lbs is just unreasonable without forced induction or nitrous.

 

[L31MaxExpress]

Then again look at this engine masters 353 cube build, over 500 ft/lbs. A 383 of the same spec would probably break 550 tq.

https://www.google.com/amp/s/www.hotrod.com/articles/get-570-hp-small-block-350-chevy-pump-gas/amp/

 

[L31MaxExpress]

...but what would it take to get 115 additional foot/lbs out of that thing? An iron lung? It's not going to happen with 33 cubic inches.

600 ft/lbs is just unreasonable without forced induction or nitrous.

Like I said Torque seems a bit high for that cubic inch but a reasonable build could easily hit 500 hp NA.

This build seems strong for a mld 383, TBH. The TPI boosts the torque and lowers the powerband limiting HP but seems like it would be perfect in a heavy truck.

http://rcsracingengines.com/Perf Crate Engines/Crate 383 HP460.T520 SB Chevy EFI.html

 

[Kyle89]

Well he did say give or take on the torque but I know for sure 500+ NA 383 is doable. But would using a 6 inch rod over a 5.7 help with the torque? Still 500+ horse for 5 grand ist bad with aluminum heads

 

[upper_tanker]

I would also ask him what compression ratio he's planning on, as that's likely a contributing factor to that amount of power that he's claiming. You're going to want to make sure that you will want to, and can afford to use whatever octane fuel that the build requires. If he builds you an 11.x CR engine, can you afford the fuel to drive it like you want? I have a 91+ tune on my Tahoe and one of the main reasons that I only drive it once a month or so is because I don't like paying $4/gallon while getting 13mpg in a DD.

Also, maybe I missed it, but what fuel system are you going with? If you're going with anything but carb, you definitely want to read up on injectors that will provide you with the amount of fuel that you need, or else the engine will lose all balls past a certain RPM, probably on the lower side.

As far as your gear question, you can see if you can find a gear ratio/tire size/mph calculator online for your NV4500. This will let you play around and see what your RPMs will be with different ratio gears and different tire sizes at different speeds.

 

[Schurkey]

Now if I have my mechanic build one with my block adding aluminum heads, he can crack 500 hp and nearly 600 ftlbs of torque for 5k with a install.

Well he did say give or take on the torque but I know for sure 500+ NA 383 is doable... ...Still 500+ horse for 5 grand ist bad with aluminum heads

I still think he's blowing smoke up your ass. But what do I know? Maybe you live next-door to some internal-combustion wizard, and he owes your family some favors, or you've got naked pictures of him with sheep or chickens.

500 REAL horses (not happy-dyno, or worse, no-dyno-best-guess horses) suitable for use in a full-size pickup with big tires, installed in the vehicle, tuned and tested for $5K? If the price was double that, I'd be a little less skeptical.

https://www.summitracing.com/parts/mll-bp38313ctc1
Blueprint engines gets "430" horsepower "dressed long-block 383" for $4655, and that isn't installed. They are offering a $400 rebate, which would approximately offset the shipping cost. And it does include the magical "ALUMINUM" heads. (I can't find a torque figure, or a dyno graph, but I'm sure you could call and ask.)

I am NOT recommending this engine, I'm just saying that a known low-budget Chinese-parts engine builder, selling through a high-volume, discount, "mail order" retailer, can't get anywhere close to 500hp/600ft/lbs, installed, for anywhere near $5K.

You're being lied to or the builder is living in fantasy-land.

 

[PlayingWithTBI]

500 REAL horses (not happy-dyno, or worse, no-dyno-best-guess horses) suitable for use in a full-size pickup with big tires, installed in the vehicle, tuned and tested for $5K? If the price was double that, I'd be a little less skeptical.

^^^What he said, does this include tuning? I'd insist on a reputable dyno. Then I'd ask myself, will my drive train hold up to this kind of HP? Got lockers in that rear end, etc? I'm nowhere near 500HP but, by the time I got it running (including $2100 for a stage 2 700r4) I'm over $8,000. It adds up quick!