LS,LQ engine/tranny swap 51 1/2 ton short bed

[R&B51]

First time posting and new to membership. Have been viewing as a guest for some time and really appreciate all you guys do to help each other build great trucks. My college age son and I am just starting our first project together. Really nice original truck. Plan is to pull the clean original solid running drive train and do an LS3 or LQ4/4L80e type swap. A little overwhelmed by this process. Maybe the first question I have is how these things drive with a modern PowerPlant like this? Seems like we always are fighting for more horsepower and I'm not sure of what Will get a really strong fun truck to drive that we can still control. Probably expecting to end up in the 350 to 425 hp range with an automatic transmission behind it. TCI coil over suspension swap have already cut the old one off and removing rivets right now. Before we do this, maybe some input from you guys about how these trucks drive. Is this horsepower range reasonable for a truck of this weight I don't want him to get in trouble with it. Will have four wheel disc and better handling but still don't want him driving a beast that he can't control. Then, is there a market for this drivetrain and I'm pulling out? School me if I'm not posting right.

[dsraven]

I suggest to buy an insurance write off so you have all the stuff you need for the engine and trans etc. unless you are gonna buy a gm crate with ecm etc. don't go too big with the hp unless you plan on going racing or something. just make it a nice ride with enough go to say it is a hot rod. spend more on the creature comforts so it is fun to drive. how often do you do full throttle anyway, right?

[dsraven]

oh ya, make sure to get the frame set up level side to side and at the rake angle you intend to end up with BEFORE you weld anything together. mock it up with tack welds and do the complete assembly, minus springs, so you know you have all the angles right first and no binding etc. THEN have it welded in.

[dwcsr]

Originally Posted by R&B51

First time posting and new to membership. Have been viewing as a guest for some time and really appreciate all you guys do to help each other build great trucks. My college age son and I am just starting our first project together. Really nice original truck. Plan is to pull the clean original solid running drive train and do an LS3 or LQ4/4L80e type swap. A little overwhelmed by this process. Maybe the first question I have is how these things drive with a modern PowerPlant like this? Seems like we always are fighting for more horsepower and I'm not sure of what Will get a really strong fun truck to drive that we can still control. Probably expecting to end up in the 350 to 425 hp range with an automatic transmission behind it. TCI coil over suspension swap have already cut the old one off and removing rivets right now. Before we do this, maybe some input from you guys about how these trucks drive. Is this horsepower range reasonable for a truck of this weight I don't want him to get in trouble with it. Will have four wheel disc and better handling but still don't want him driving a beast that he can't control. Then, is there a market for this drivetrain and I'm pulling out? School me if I'm not posting right.

This truck with 425 hp will be a rocket, The truck weighs a lot less than a new vehicle and isn't put together nearly as well. When they get hit or hit something at high speed (50 mph) the turn into origami. I just built a 1950 with a LC9 4L65e 330 hp an its a rocket. 4 wheel disc, new steering column, and better suspension make then ride nicer and handle better. It will never handle like a Camaro no matter what you do so keep that in mind.

[dsraven]

take some time to research the geometry of the front end so you know what the specs and measurements are supposed to be and how everything works together as you are assembling and tacking it all together. it will save you time in the long run and you won't end up with some of the problems seen in the forums. sometimes the directions can be vague or even the wrong sheet or parts were supplied so if you know what to look for you will spot a problem before it is to late.like dwcsr says, they are light trucks so it doesn't take much to make a rocket. even a 4.8 is gonna make it fly, so be sure to make it stop fast as well.

[Hampshire]

Excellent advice from the other posters. I'm running a GM crate slightly modified for 325 & high torque with a TKO 5 Spd behind it. IFS, 4 wheel power disc, Coil overs all around, front sway bar, rear panhard and a lot of attention to other details that went to improved handling.

I built it to drive & enjoy just going down the road, one arm on the window sill. If I want, it will scream through gears & by the time I leave third I'm well past any speed limit & maybe going faster than what really feels safe. It stops an a dime and it's fun/comfortable to drive through twisty roads. There a lot of peer pressure out there to have/say you have 400+ Hp. For race, for sure - for the show truck , that can be also very important - it's all part of the presentation (which is cool). Going down the road on a more regular basis, however, I think the other posters have it right.

[e015475]

I'll chime in with my opinion - and it is worth just what you paid for it, but here goes.

The LS3 and the LQ4 are fine engines - but you'll pay quite a premium for them. They are relatively rare compared to all the other LS motors GM put in cars and trucks since the late 90's. Around here is is hard to find a LQ4 complete for less than $2000 and the aluminum LS3 can easily go 2X that.

A 350-400 hp vehicle that weighs 3100 lbs should be in the mid-12 second quarter mile, assuming you can get it to hook up.

The 5.3L LM7 and its aluminum block cousins, the L33 and the L4, on the other hand ----you can't hardly swing a dead cat without hitting one. Cheap and plentiful in a lot of salvage yards. With the addition of a mild cam, some better springs, decent intake and a little tuning to move the rev limiter up a bit, it'll hit the 350 -375 pretty easy. Spend the money you save on a good 9" diff with a four-link and a good dyno tune. I'd love to have that TKO that Hampshire has or a T56, but that's personal preference.

What I think you're looking for is balance. A warm 5.3L, a rear suspension that will hook up and good brakes make for a much more user friendly truck that you'll love to drive.

If money's no object, go get a LS3 and put it in an Art Morrisson chassis and have a blast too

[Hampshire]

If money's no object, go get a LS3 and put it in an Art Morrisson chassis

...seriously - what a great way to go if you got the $

[R&B51]

Thanks, your experience and your having driven your builds is something I can trust. I'll start moving on your advice.
My son has worked for years and saved and I'm gonna pitch in some. Never know how many times we're gonna actually get this done so are gonna stretch for best we can swing at. This'll be a really solid driver so your HP and suspension advice will be taken.
Crazy, as much as I enjoy and look forward to the bustin my knuckles, I'm liking the mental part of this just as much. You guys are the "professors" and class has begun! Never had so much fun with homework. They really ought to bring high school shop back and build old trucks with kids using teachers that bring math, reason and problem solving to the table. Sorry, didn't mean to ramble.
Will try to stick to questions from now on.

[Advanced Design]

Originally Posted by R&B51

They really ought to bring high school shop back and build old trucks with kids using teachers that bring math, reason and problem solving to the table.

Welcome R&B51! I strongly agree. You should check out farm trucks "High School Build II" in the 67 to 72 trucks section. Some years ago I read an article about a high school auto instructor in Wisconsin that did that. A high percentage of his students went into mechanical engineering.

As for horsepower, how much driving experience does your son have? A stock 5.3 from a Silverado will really make these AD trucks scoot. If you haven't, go drive a Silverado at wot from a dead stop to feel the acceleration. Then imagine that in a much lighter truck. It might be sufficient for the goals you have.

[e015475]

Well, true confession time -- I've not actually driven mine yet. Having said that, I've built a few LS1 and LM7 powered vehicles and engines ranging from 285HP to 525HP.

Like you, I have a great deal of fun thinking about how I'm going to put my next project together, and your post got me thinking about a LQ4 powered truck I saw last week.


Friday I'd stopped at a shop to talk about the paint job for my truck. There was a Chevy AD truck there with a 6L LS motor sitting in a S10 frame in for some work. My first question is always "how does it drive?" The answer - "it goes like stink, but it is scary" There were no upgrades to the S10 suspension and the front wheels were 6" away from the lip of the front fender but the rears were almost rubbing. The doors wouldn't close all the way and I didn't want to ask if they'd ever popped open while driving. It looked cool, but the owner had to fight with it just to get it down the road - but by-golly he had an LQ4! Don't get me wrong, there's lots of well-executed S10 frame swaps on this board, and maybe that's even right for you. LQ4s too, but the owner of the truck was pretty frustrated. To me, it was the complete antithesis of of a truck like Hampshire's that does everything well (and what I aspire to with mine).

Hope you have as much fun as I do scheming and planning on these things . My son is 30 years old now and out of college and working, but some of the best memories are the car projects we did together while he was growing up (and sometimes the only thing we could talk about without arguing!) He's coming over next weekend to help me build a LS1 with a forged bottom end for another project - really looking forward to it.

Regards

[e015475]

Buying a complete running vehicle to harvest the drivetrain for a project is a great way to go. I wish I had the room and patience with having to sell all the parts to cover my cost. Really nervous about people tromping around in my shop & yard to buy parts.

Pretty sure my wife'd have my head on a stick if I tried this though.

There's and interesting thread over in the Engines section of this board talking about this same subject

http://67-72chevytrucks.com/vboard/s...d.php?t=687747

[THEE OG]

I opted for the lq4 in my build. Not trying to build a race car. So the extra weight will be ok with me. Also they are strong motors. A few mods to bolts and they truly are ready for anything.

I just picked up a van with a lq4 and 4l80e that had some front damage for 2000$ and it has a service box that will be on the market next week and have had offers for already for around a grand.