5.7 vortec or 5.3LS?

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L31MaxExpress

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One of the lessons I learned from playing with 500cid Cadillac motors is that more gear is a crutch for motors with no torque.
Absolutely. Tahoe has 32" tires and 3.42s with the 4L80E. It runs like 1,800 rpm going down the highway and even pulling 6,000+ lbs of flat deck car hauler trailer + car on it, will hold overdrive almost the whole trip.

One of the 500 I had my hands on had a switch pitch built FWD TH425 from the days the GMC had a 403 Olds in it. Moved a 26' long, 12,000 lbs motorhome easily at 10 mpg with port fuel injection. Used a modified stock Caddy 500 PFI intake, with a GM454 TBI sans injectors and a custom tuned 7730 TPI ECM. Switch pitch in a motorhome is awesome, when it is in high stall mode from a stop the 500 would burn the front tires off it. The 403 got like 6-8 mpg previously with a Q-Jet because it was either in 2nd gear or into the secondaries in 3rd to run 65 mph. The 2nd 500 was in a late 70s K5 on 37s. Stock 3.42 gears. That 500 could get 17 mpg pulling around that K5 with a Q-Jet and no overdrive. My other Cadillac experience was a 425 into an 82 G30 cut-away van motorhome to replace a tired low compression 160 hp 350. Q-Jet carbed 425 hauled its 10,000 lbs around effortlessly.
 
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Supercharged111

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I liked my 8.1L in my Tahoe and with tall gear and 4L80E is reasonable of fuel. Now that the van is done I can move back to going through the bottom end and getting the heads back on the 8.1L. It burned #8 exhaust valve over a year ago. It had 80K but apparantly a huge amount of idle time on in when I got it. One of the lifters got sticky and was hanging the valve open causing it to burn.

This was my inspiration for my L31 383 build.

I recently had a 2015ish L83 5.3L truck with some kind of loud exhaust try to jump in front of me out of a traffic light getting on to an onramp. Until 30 mph we were side by side, then the 383 easily showed him Express van tail lights. 4L85E and 3.73s do not have the greatest acceleration from a stop but the 383s torque has no problem pulling that gear combination.

Doesn't hurt that he likely had to shift out of first at 30, and that probably happened at a snail's pace.
 

Brothajack93

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i know, well done!

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If i have to use force whoever is being a meanie gets a 0w-40 enema
just starting to realize, maybe a lil late in life that it’s not worth getting worked up over opinionated people on the internet and trolls. As much as I love chevys and most of the response I get from posts I make asking questions are helpful and informative I’ve come to accept that there is always going to be one or a few who want to be insulting or impose their personal views and I just gotta live with that and not get into big comment section wars cause it makes no difference. In every community there are going to be people like that and I just gotta deal with it. So now my strategy is simply tell them that they’re being an ass for no reason and move on. I have lots of questions that I will be asking cause I don’t know much of anything about mechanical aside from basic suspension and tune up work so I try to ask people who know the details of these specific trucks cause my mechanic friend who’s helping me out is a ford guy and doesn’t know all the how to’s, compatibility and conversions that are possible in these trucks. I also like to come to gmt400 here because people are more detailed and honest when giving advice compared to Facebook groups where guys will say “I did it no problem” with little detail of what it took to accomplish so anything I see on there I like to bring here for more expert confirmation and advice from the experts. I’ll probably be making a thread here soon abut frame/chassis compatibility and I’m sure the comments will flood in about how I should just scrap it and start over again but that’s not what I’m trying to do here. I want to learn to do the work and since it’s beyond repair by most peoples standards anyway the worst I could do is mess up some scrap anyway….. or I could build some skills and bring back at least the part of the truck that’s already registered and a lot of people in these parts could use. Chassis aren’t always as bad as mine but cabs almost always are unless already repaired or properly cared for their entire lives so whether I use it or sell it to someone who will be very happy to have what they need and not have to pay a southern parts premium for. For some people it doesn’t even have to be pretty just passable cause they don’t want to scrap their chassis and drivetrain so it’s worth it for both my experience and also saving a Canadian body when so many have been lost and the value of these trucks has gone up about 500-600 percent since my first truck almost 10 years ago. The biggest lesson I’ve learned by far was the mistake of my purchase and now I know in the future what to look for when investing in a truck or project. Yes it’s cost me a lot of money and will cost me more than it’s worth in the end but the knowledge and abilities I’ll have when it’s done will be priceless to me cause I intend to make a hobby of keeping these trucks alive and being able to do most of the work myself. Every bit of knowledge I learn from this experience will hopefully help more than myself in the future if all goes well because I’m not the only broke guy with no mechanical knowledge looking for a truck in the land of salty roads and body guys are hard to come by. I’ve always had a passion for it but could never get my foot in the door to learn and do it professionally. Plus all I’m gonna learn in a body shop is how to replace plastic bumpers. Guys who can fabricate, weld and grind smooth body panels with little to no filler are hard to come by. The classic truck community needs young people to learn the skills or northern trucks are doomed and so will southern trucks when they get bought to come up here and meet the same fate. I may be an idiot (an ignorant one not clueless) for my mistake but it’s a learning opportunity that I plan to take full advantage of. I want to save these trucks and my bad purchase is a good chance to learn. At the end of the day it’s my mistake and my unreasonable amount of work put into fixing it and learning to make the upgrades. It’s no longer about getting the truck on the road to suit my needs for a reasonable price. It’s about fixing the common body problems they have in the north when no one else will so less of them see the scrapyard for things like cab corners, rockers, floor pans, body mounts etc and a lot of southern guys don’t understand that our rotting trucks eventually become their problem. Not like I’m asking them how to do body work. I can get that from YouTube. I’m asking about compatibility and upgrades that would help with projects and building trucks to suit personal needs as well as working with what’s available at the time. For that I lean on the obs Chevy community for expertise cause it’s not like there’s a dedicated YouTube channel for that. I can safely say I’ve learned a lot from all you guys. Even how to not be a rage monger when dealing with the “toxic Chevy guys”
 

AuroraGirl

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just starting to realize, maybe a lil late in life that it’s not worth getting worked up over opinionated people on the internet and trolls. As much as I love chevys and most of the response I get from posts I make asking questions are helpful and informative I’ve come to accept that there is always going to be one or a few who want to be insulting or impose their personal views and I just gotta live with that and not get into big comment section wars cause it makes no difference. In every community there are going to be people like that and I just gotta deal with it. So now my strategy is simply tell them that they’re being an ass for no reason and move on. I have lots of questions that I will be asking cause I don’t know much of anything about mechanical aside from basic suspension and tune up work so I try to ask people who know the details of these specific trucks cause my mechanic friend who’s helping me out is a ford guy and doesn’t know all the how to’s, compatibility and conversions that are possible in these trucks. I also like to come to gmt400 here because people are more detailed and honest when giving advice compared to Facebook groups where guys will say “I did it no problem” with little detail of what it took to accomplish so anything I see on there I like to bring here for more expert confirmation and advice from the experts. I’ll probably be making a thread here soon abut frame/chassis compatibility and I’m sure the comments will flood in about how I should just scrap it and start over again but that’s not what I’m trying to do here. I want to learn to do the work and since it’s beyond repair by most peoples standards anyway the worst I could do is mess up some scrap anyway….. or I could build some skills and bring back at least the part of the truck that’s already registered and a lot of people in these parts could use. Chassis aren’t always as bad as mine but cabs almost always are unless already repaired or properly cared for their entire lives so whether I use it or sell it to someone who will be very happy to have what they need and not have to pay a southern parts premium for. For some people it doesn’t even have to be pretty just passable cause they don’t want to scrap their chassis and drivetrain so it’s worth it for both my experience and also saving a Canadian body when so many have been lost and the value of these trucks has gone up about 500-600 percent since my first truck almost 10 years ago. The biggest lesson I’ve learned by far was the mistake of my purchase and now I know in the future what to look for when investing in a truck or project. Yes it’s cost me a lot of money and will cost me more than it’s worth in the end but the knowledge and abilities I’ll have when it’s done will be priceless to me cause I intend to make a hobby of keeping these trucks alive and being able to do most of the work myself. Every bit of knowledge I learn from this experience will hopefully help more than myself in the future if all goes well because I’m not the only broke guy with no mechanical knowledge looking for a truck in the land of salty roads and body guys are hard to come by. I’ve always had a passion for it but could never get my foot in the door to learn and do it professionally. Plus all I’m gonna learn in a body shop is how to replace plastic bumpers. Guys who can fabricate, weld and grind smooth body panels with little to no filler are hard to come by. The classic truck community needs young people to learn the skills or northern trucks are doomed and so will southern trucks when they get bought to come up here and meet the same fate. I may be an idiot (an ignorant one not clueless) for my mistake but it’s a learning opportunity that I plan to take full advantage of. I want to save these trucks and my bad purchase is a good chance to learn. At the end of the day it’s my mistake and my unreasonable amount of work put into fixing it and learning to make the upgrades. It’s no longer about getting the truck on the road to suit my needs for a reasonable price. It’s about fixing the common body problems they have in the north when no one else will so less of them see the scrapyard for things like cab corners, rockers, floor pans, body mounts etc and a lot of southern guys don’t understand that our rotting trucks eventually become their problem. Not like I’m asking them how to do body work. I can get that from YouTube. I’m asking about compatibility and upgrades that would help with projects and building trucks to suit personal needs as well as working with what’s available at the time. For that I lean on the obs Chevy community for expertise cause it’s not like there’s a dedicated YouTube channel for that. I can safely say I’ve learned a lot from all you guys. Even how to not be a rage monger when dealing with the “toxic Chevy guys”
If thats not considered growth and character progression and wholesome I dont know what is.

Id still happily give a 0w-40 enema to someone if they are into that LOL
 
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