Budget 383 vortec sleeper build.

[Jesse_Wenting]

360 thousand km 96 350 block 2 bolt main and stock heads. Obviously having everything cleaned and fluxed by the machine shop. Sticking with the stock L31 intake. Plan is a B13004L03053 kit from Eagle, along with pushrods, lifters, oil pump, seals and gaskets, timing chain, water pump and a yet undecided mild cam. All other external accessories will be transferred from my current 98 vortec 305

Goal is 350-400hp at the crank on pump gas, will be going into a daily driver, and spend most of its life between 1500 and 4000rpm the with factory 5500rpm rev limit.

Overall well experienced, but first time builder, be gentle with me . Send me in the right direction, either with parts or my expectations. Do I need threaded rocker studs, cam recommendations for my use case, other stuff I haven't thought of etc.

Looking at you @L31MaxExpress you 383 wizard

 

[L31MaxExpress]

What are you intending on doing outside of the engine. You have oversized tires, do you have gears? Are you intending to upgrade the torque converter? Are you going to run headers? Are you planning to keep the stock air intake system after the throttle body? Who is doing the tuning? Will this have to go through smog with the 305s single catalyst exhaust?

Threaded rocker studs are not necessary until you get to a fairly substantial spring rate, lift and rpm.

While you can definitely achieve that power goal, what are you willing to live with as far as idle quality and fuel octane. Is it worth bumping the compression up enough to require premium fuel to get another 20-30 ft/lbs of torque? What altitude are you going to operate this in? What works at sea level gives up a good bit climbing 12,000 ft mountain passes. What you can get by with at high elevation would not be friendly to tow a trailer through death valley with either.

Just trying to figure out some details.

 

[L31MaxExpress]

Where you want your power, I would simply clone the HT383 in terms of camshaft specs. You will not get 350-400 HP (more like 330 hp), but it will have the powerband where you want it, run on pump gas, have a good idle quality, can pass smog and overall just a good choice for a heavy truck. The HT383 under the L31 intake manifold peaks at about 4,600-4,800 rpm and peak torque is about 3,000 rpm. It is for all purposes an L31 that makes more power everywhere. If you are going to upgrade the gears and converter, I would use something like a LPE-74211 or LPE-74219. Comp, Howards, and other manufactures have cams that would also work about the same. 400hp is not what is needed to move your truck, IMO. Its the 400+ ft/lbs that the combination can make at low-rpm and the 430-450 ft/lbs it makes right in the 3,000 rpm range.

 

[Jesse_Wenting]

Just gonna fire off answers to each and every thing, you're gonna see "stock" a lot lol

You have oversized tires, do you have gears?

Currently running 285/75r16 with a 3.42 10 bolt, but I need tires before this winter so I'm going down to 235/85r16s and I found a 6 lug SF 14 bolt locally. I don't know if I'll end up with the 14 bolt since I'm pretty set on a Detroit Truetrac (don't know if they make it for the 9.5"). Will be gearing to 3.73 within the next 18 months regardless of what axle I choose

Are you intending to upgrade the torque converter?

I rebuilt my 4L60e less than 30k miles ago so I'm going to stick with it as long as I can. After that if I need something stronger a 4L75e or 4L80e are the most likely ways forward.

To actually answer though right now I'm using the stock 1500rpm-ish stall TC. Wasn't planning to upgrade until the next transmission goes in unless needed.

Are you going to run headers?

Not currently but it's something I'll inevitably do. Will be shorties to maintain compatibility with a stock exhaust system for any future owners.

Are you planning to keep the stock air intake system after the throttle body?

Ideally yes, I do want to ditch the ribbed portions for smooth tubing to reduce turbulence but I'd like to keep the factory look as much as possible.

Who is doing the tuning?

Me. I'm running a 98 305 that replaced my 350 so I still have the spare PCM (Have to tell shops to use the VIN on the dash lol). Plan is to learn HP Tuners, start with a 383 tune from the community and go from there

Will this have to go through smog with the 305s single catalyst exhaust?

Currently running the stock single cat Y pipe, got it for a steal so I'd like to keep it. Eventually I'll be changing to the OEM style dual cat followed by a X pipe into a dual in/out muffler. Again trying to maintain compatibility with other stock exhaust parts for any future owners.

Smog tests are not a concern but I do like to do what I can for the environment so no gutting.

Is it worth bumping the compression up enough to require premium fuel to get another 20-30 ft/lbs of torque?

Premium fuel is not an option. Full stop lmao

What altitude are you going to operate this in?

On average 300-500ft, maybe 5 times a year I'll be up at 1500-1700ft, I don't expect to ever be up at 2500ft with this setup

 

[L31MaxExpress]

My $0.02 on this. Zero deck the block, 0.038" compressed head gaskets. That should put you where you need to be quench wise. Then use this GM cam. Basically duplicating the HT383E. Tuned correctly the HT383E is capable of 450 ft/lbs @ 3,000 rpm. With the correct tuning it will run well on 87 and work with stock manifolds, stock converter and stock gearing. It will run out of steam at ~5K but make good torque everywhere. I would drill out the pushrod holes now, put the GMPP LS springs and Comp787 retainers on it. That would give you an easy upgrade to 1.6 full roller rockers for about 15-20 hp gain later. I ran 1.7s on that cam in my L31 at one point and they gave even more HP/TQ without sacrificing the smooth idle, low-speed torque and fuel mileage. You could go a bit bigger on the cam, but you will not get the same stump pulling torque with your 1,500 rpm stall speed. A 4.3W S10 converter for your year transmission would get that engine up to 2,500 rpm at WOT from a stop and it could run something like a 212/218 @ 0.050 with excellent results. With a bit higher stall speed the CC304 is not a bad cam either. It is 210/220 @ 0.050 on a 112 LSA and idles smooth. Comp Cams wants $528 for a cast core roller now and that is highway robbery compared to the $268 GM steel roller cam. Then again the 7395 cam was $148 from GM when I put one in my Express back in 2014ish.

Chevrolet Performance 14097395 Chevrolet Performance Hydraulic Roller Camshafts | Summit Racing

Free Shipping - Chevrolet Performance Hydraulic Roller Camshafts with qualifying orders of $109. Shop Camshafts at Summit Racing.

www.summitracing.com

 

[62barsoom]

See this a great example of why I joined y'alls forum. The knowledge so freely shared is amazing. Right now I'm just trying to get the 99 Tahoe on the road. Planning on building a low budget motor in the spring hopefully. Thanks for giving me some thoughts and pointing my research in the right direction. My stats are pretty much in line with Jesse's other than operating at 2000' to 4000' altitude. I'd be towing fairly often so the extra oomph would be welcome here in our West Virginia mountains.

 

[62barsoom]

My $0.02 on this. Zero deck the block, 0.038" compressed head gaskets. That should put you where you need to be quench wise. Then use this GM cam. Basically duplicating the HT383E. Tuned correctly the HT383E is capable of 450 ft/lbs @ 3,000 rpm. With the correct tuning it will run well on 87 and work with stock manifolds, stock converter and stock gearing. It will run out of steam at ~5K but make good torque everywhere. I would drill out the pushrod holes now, put the GMPP LS springs and Comp787 retainers on it. That would give you an easy upgrade to 1.6 full roller rockers for about 15-20 hp gain later. I ran 1.7s on that cam in my L31 at one point and they gave even more HP/TQ without sacrificing the smooth idle, low-speed torque and fuel mileage. You could go a bit bigger on the cam, but you will not get the same stump pulling torque with your 1,500 rpm stall speed. A 4.3W S10 converter for your year transmission would get that engine up to 2,500 rpm at WOT from a stop and it could run something like a 212/218 @ 0.050 with excellent results. With a bit higher stall speed the CC304 is not a bad cam either. It is 210/220 @ 0.050 on a 112 LSA and idles smooth. Comp Cams wants $528 for a cast core roller now and that is highway robbery compared to the $268 GM steel roller cam. Then again the 7395 cam was $148 from GM when I put one in my Express back in 2014ish.

Chevrolet Performance 14097395 Chevrolet Performance Hydraulic Roller Camshafts | Summit Racing

Free Shipping - Chevrolet Performance Hydraulic Roller Camshafts with qualifying orders of $109. Shop Camshafts at Summit Racing.

www.summitracing.com

Am I reading this correctly? Your parts suggestion on an L31block?

 

[351FUN]

Very similar to what I did. I'll have to double check but I think that's the same eagle kit I'm running too. Stock TBI block, swapped to vortec heads and an aftermarket cam along with a carb swap too. Heddman longtubes tied into the 3" single exhaust it already had with a Borla XR1 like everything else. My next move is gears for sure, probably 4.56 since I'm on 285/75's but maybe 4.88 to give a little future room. I never get about 65 and right now I'm at 1600 rpm commuting.

 

[Schurkey]

If you're buying Eagle parts, have your local machine shop verify EVERYTHING. Crank journal diameter, roundness, and taper, connecting rod big-end diameter, roundness, etc. And don't get me started on their "balance".

Eagle doesn't have a good reputation for quality. Even Scat seems to be better.

 

[Supercharged111]

If you're buying Eagle parts, have your local machine shop verify EVERYTHING. Crank journal diameter, roundness, and taper, connecting rod big-end diameter, roundness, etc. And don't get me started on their "balance".

Eagle doesn't have a good reputation for quality. Even Scat seems to be better.

They still suck? They sucked 20 years ago, you'd think they'd get wind of that and maybe want to do something about it?