Hi all,
I'm Jay. I'm new here. I bought a 1999 K2500 Suburban a while back and now I'd like to make it into a good towing/roadtrip rig for myself and my friends. I really like this generation of GM trucks. Prior to this I've only owned Squarebodies. I bought this one for EFI, Overdrive (4L80 - no 4L60's allowed here), lots of seats, and A/C. I'll do a build thread on it here when stuff gets serious but for now I just want to talk engine.
I bought this truck for $1000 at an insurance auction. It's catalytic converters and drive shaft had been stolen, and it was listed as "possible engine damage" since it wouldn't start. I bought a parts truck for $400 and got a driveshaft, all the exhaust, and a new fuel tank + pump. Now it starts/runs/drives (fuel pump was shot).
The truck currently has a stock 5.7L L31 Vortec 350 with 260K KMs on it (162,500 Mi). It runs, clean oil, sounds fairly healthy (can't really tell if it ticks or anything because it has no exhaust at the moment).
I don't know the history of this truck, other than it was a fleet truck for a rural cable company for a large part of it's life. I feel like 255 HP / 330 TQ or whatever the Vortec 350's were rated for will be a little less than I want for it. I'd like to pull the engine out and get it redone as a 383. Here's what I got so far:
- stock 1999 5.7 Vortec L31
- 4.10 gears
- 4L80E being rebuilt with Jake's Performance B82 Billet converter (2200-2400 stall - basically an S10 converter)
I will be doing the 0411 swap and keeping the EFI. I have a marine intake that looks like a square-bore 4150 dual plane carb intake but has injector bungs in the runners. It's from a Mercruiser boat engine and it works with Vortec heads. I plan to use this with fuel rails and some 36-42 LB LS-engine-type injectors (either the 36LB supercharged 3800 V6 injectors that all the LS1 boys use, or the bigger 42LB ones found on 2010 or so 6.0L V8 truck engines with Flex Fuel). I'll get a pic of this intake shortly.
I want to use my fancy marine intake (pics to come later) and that leaves me with vortec heads. I hear that later Vortec heads (like, after 1998) are made in Mexico and have only 160CC runners, making them a bad choice. This, combined with the fact that these heads are well-known to crack - maybe I should get something else before I throw money at these making them support more lift and screw-in rocker studs. I like iron heads for truck motors. I'm thinking the EngineQuest EQ Vortec Head 350C. These can be had bare on ebay for $275 a side. My machinist will add springs and valves. They have revised water passages and thicker decks, plus screw-in studs from the factory. Anyone here use these?
What would you run for heads/cam on a L31 383?
I'm thinking iron heads and 9.3:1 compression.
4L80 & 4.10's put it just over 2000 RPM in 4th on the highway (65 MPH) with 33" tires.
Downshifting to 3rd to pass puts me at 2700 RPM.
Downshifting again to 2nd for towing heavy uphill takes me to 4000 RPM (roughly my peak power).
I would like max torque and decent fuel economy.
I'm thinking to go with the 395 HT383/Ramjet Cam from GM and basically build myself an HT383E.
GM advertises these as 323 HP @ 4200 and 444 TQ @ 3000.
Hotrod did an article where they got one up to 379 HP @ 4600 and 474 TQ @ 3700 with 1.6 rockers, an air-gap manifold and a bigger carb (not far off from my marine intake and throttle body).
https://www.hotrod.com/articles/gm-ht383-crate-small-block-tune-up/
Most importantly, they got the torque up to 450 LB/FT at 2500 RPM (roughly my converter stall speed).
I've been told that something like a Comp Cams Extreme 4x4 Cam might get me even more torque down low, but I'm not sure I want to thrash the valvetrain with super aggressive lobes on an engine that I want to tow across the country with. I'm happy to go full roller rockers and all that if it's a good idea. This engine was roller cam from the factory.
I need it to run on 87 octane and get decent fuel economy. I'm in Canada and our fuel options suck here. 91 octane is almost 20% more money than 87 so it doesn't really make sense for a truck.
I have EFI Live for tuning and I fear nothing electrical. I don't want to go LS engine because low-mile 6.0L truck engines (LQ4, etc) don't really exist here, and if they do - people want a fortune for them. Also I've always thought they don't quite have the torque down low that the old Vortecs did. I'd rather throw money at an all new forged 383 stroker and get more cubes than spend thousands on a stock engine I don't know the history on. It'll be 0411'ed anyways, so all an LS engine gets me is access to cheap aluminum heads - and I don't even like aluminum heads (for a truck).
Thanks for reading and thanks for your input,
- Jay
P.S. I built a 243 headed LS1 with a buddy for a Camaro that goes like hell. LS engines are awesome.. for stuff like cars. Or if you stroke them with 4" cranks. Or Forced induction. Or with a high stall converter and no plans to tow. For whatever reason I've always felt like they don't get going until 3500 RPM. I come from diesels, so this drives me insane. Some of your LS rides will smoke me all day long - so don't take my LS jabs as a dis. They were born to rev. I am not. Thanks again!
I'm Jay. I'm new here. I bought a 1999 K2500 Suburban a while back and now I'd like to make it into a good towing/roadtrip rig for myself and my friends. I really like this generation of GM trucks. Prior to this I've only owned Squarebodies. I bought this one for EFI, Overdrive (4L80 - no 4L60's allowed here), lots of seats, and A/C. I'll do a build thread on it here when stuff gets serious but for now I just want to talk engine.
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I bought this truck for $1000 at an insurance auction. It's catalytic converters and drive shaft had been stolen, and it was listed as "possible engine damage" since it wouldn't start. I bought a parts truck for $400 and got a driveshaft, all the exhaust, and a new fuel tank + pump. Now it starts/runs/drives (fuel pump was shot).
The truck currently has a stock 5.7L L31 Vortec 350 with 260K KMs on it (162,500 Mi). It runs, clean oil, sounds fairly healthy (can't really tell if it ticks or anything because it has no exhaust at the moment).
I don't know the history of this truck, other than it was a fleet truck for a rural cable company for a large part of it's life. I feel like 255 HP / 330 TQ or whatever the Vortec 350's were rated for will be a little less than I want for it. I'd like to pull the engine out and get it redone as a 383. Here's what I got so far:
- stock 1999 5.7 Vortec L31
- 4.10 gears
- 4L80E being rebuilt with Jake's Performance B82 Billet converter (2200-2400 stall - basically an S10 converter)
I will be doing the 0411 swap and keeping the EFI. I have a marine intake that looks like a square-bore 4150 dual plane carb intake but has injector bungs in the runners. It's from a Mercruiser boat engine and it works with Vortec heads. I plan to use this with fuel rails and some 36-42 LB LS-engine-type injectors (either the 36LB supercharged 3800 V6 injectors that all the LS1 boys use, or the bigger 42LB ones found on 2010 or so 6.0L V8 truck engines with Flex Fuel). I'll get a pic of this intake shortly.
I want to use my fancy marine intake (pics to come later) and that leaves me with vortec heads. I hear that later Vortec heads (like, after 1998) are made in Mexico and have only 160CC runners, making them a bad choice. This, combined with the fact that these heads are well-known to crack - maybe I should get something else before I throw money at these making them support more lift and screw-in rocker studs. I like iron heads for truck motors. I'm thinking the EngineQuest EQ Vortec Head 350C. These can be had bare on ebay for $275 a side. My machinist will add springs and valves. They have revised water passages and thicker decks, plus screw-in studs from the factory. Anyone here use these?
What would you run for heads/cam on a L31 383?
I'm thinking iron heads and 9.3:1 compression.
4L80 & 4.10's put it just over 2000 RPM in 4th on the highway (65 MPH) with 33" tires.
Downshifting to 3rd to pass puts me at 2700 RPM.
Downshifting again to 2nd for towing heavy uphill takes me to 4000 RPM (roughly my peak power).
I would like max torque and decent fuel economy.
I'm thinking to go with the 395 HT383/Ramjet Cam from GM and basically build myself an HT383E.
GM advertises these as 323 HP @ 4200 and 444 TQ @ 3000.
Hotrod did an article where they got one up to 379 HP @ 4600 and 474 TQ @ 3700 with 1.6 rockers, an air-gap manifold and a bigger carb (not far off from my marine intake and throttle body).
https://www.hotrod.com/articles/gm-ht383-crate-small-block-tune-up/
Most importantly, they got the torque up to 450 LB/FT at 2500 RPM (roughly my converter stall speed).
I've been told that something like a Comp Cams Extreme 4x4 Cam might get me even more torque down low, but I'm not sure I want to thrash the valvetrain with super aggressive lobes on an engine that I want to tow across the country with. I'm happy to go full roller rockers and all that if it's a good idea. This engine was roller cam from the factory.
I need it to run on 87 octane and get decent fuel economy. I'm in Canada and our fuel options suck here. 91 octane is almost 20% more money than 87 so it doesn't really make sense for a truck.
I have EFI Live for tuning and I fear nothing electrical. I don't want to go LS engine because low-mile 6.0L truck engines (LQ4, etc) don't really exist here, and if they do - people want a fortune for them. Also I've always thought they don't quite have the torque down low that the old Vortecs did. I'd rather throw money at an all new forged 383 stroker and get more cubes than spend thousands on a stock engine I don't know the history on. It'll be 0411'ed anyways, so all an LS engine gets me is access to cheap aluminum heads - and I don't even like aluminum heads (for a truck).
Thanks for reading and thanks for your input,
- Jay
P.S. I built a 243 headed LS1 with a buddy for a Camaro that goes like hell. LS engines are awesome.. for stuff like cars. Or if you stroke them with 4" cranks. Or Forced induction. Or with a high stall converter and no plans to tow. For whatever reason I've always felt like they don't get going until 3500 RPM. I come from diesels, so this drives me insane. Some of your LS rides will smoke me all day long - so don't take my LS jabs as a dis. They were born to rev. I am not. Thanks again!
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