Has anyone done a LS conversion in their truck?

In My Humble Opinion
1

I recently acquired a really sweet all original 1981 Chevrolet C20 Silverado 3/4 Ton truck from a business across the parking lot from my work for a song. They only used it to move traffic cones from job site to job site.

It has the original 350 in it with the three speed TH350 transmission. I cleaned up the engine, put new intake and head gaskets and valve seals in the heads. It has the original kinda crappy Rochester 4 barrel carburetor on it.

It runs pretty good. I was always a fan of the straight six engines that they had in these, but they are really gas hogs. Eventually this thing is going to get a full restoration, and at that point, it is only going to make sense to properly redo the engine.

I live in the mountains, and I have been considering ditching the carb for fuel injection. Instead of going through the effort of replacing the top end of the engine, I am considering just doing away with the whole small block chevy setup and installing an LS engine into the thing, and either a modern 4 speed transmission or converting the old turbo 350 with a gear vendors unit.

Has anyone done this before, and was it worth all the effort? What were the gas mileage gains? I don’t drive very much so I don’t NEED a gas mileage improvement, but it would be nice.

2

Not the forum for max responses, but I’ve never seen an unhappy LS conversion (if done right).

Nobody woke up in a sweat wishing they had their old carbed 350 engine and regretted what the LS brought to the table.

Combining with the trans upgrade, the MPG will easily see a 20% jump. Note your rear gear ratio could be a consideration. Don’t know it, but the RPM at cruising speed might be too high or low for the LS. The entire power curve is better.

3

Chevrolet Performance Parts offers pretty much a complete package to do this. they call it the “E-Rod” system. You can put together a complete powertrain with LS3 (~420 hp), PCM, TCM, wiring, and automatic trans. Plus it comes with catalysts and is CARB approved for any vehicle older than 1995 (if that matters to you.)

4

I checked out the E-Rod system you just sent. Man, it seems a little steep for what it is, but at the end of the day, you only do it once…

I have found a few 4.8 and 5.3 LS engines for dirt cheap used. I might have to piece something together. I am torn between remaking the 350 block into a 383 stroke package (so the numbers will still match) and then doing direct injection on that, or just putting in an LS.

Either way I would like to go fuel injection for the altitude shifts I drive through, but I am not looking forward to converting BOTH of my tanks to run fuel injection. It seems like it would be easier to put an inline fuel pump and little pony pressure tank under the hood for the fuel injection.

5

Go to here for all the LS engine questions you may have. It has been a great resource for me. It is a v-Bulletin message board much like this one. I have been there forever. But like this message board, don’t use the search function. Use Google and search like ls1tech stroker issues or whatever you are looking for. An afternoon of reading and searching may save you a lot of time and money. It is a great car-guy resource with knowledgeable people and few kids who don’t know what they are talking about. Very professional. You can find instructions for almost everything, and read the mistakes others have made, and then make up your own mind.

6

you can definitely do it piecemeal with a compatible engine.

7

So no one else was thinking LS = lightspeed? “But officer, my speedometer showed I was barely going faster than 1e-7c!”

8

Lightspeed is a task for a 4600 pound metal hunk of left over 1970’s awesomeness, thats for sure. But it should be nearly possible if I understand physics and Matthew McConaughey movies.

I guess I should have been a little more descriptive for anyone just learning what this is.

A “Small Block Chevrolet” engine is a line of engines that General Motors used to put in cars and trucks. They started the engines out in 1954 I think. These engines were super popular and interchangable, and were (still are aftermarket) produced well into the 1990s, until they started to phase them out with the “LS” engine series. That started out the LS stuff in the mid to late 1990s. Similar engines were used in a Corvette that is used in my truck (different tuning of course.)

The small block chevy, or SBC, has a huge following still, but they aren’t very efficient by today’s standards. The new current LS engine platform is modern, aluminum, light weight, and makes more horsepower and torque for less gasoline. Think going from a VCR to Blu Ray high def. You can watch Encino Man on both formats, but Pauly Shore is much more Pauly Shore in high def.

My old engine is run by a carburetor. This is a purely mechanical way of mixing the gas and air for the engine to run on. They don’t like changes in altitude because the air changes density, throwing the mixture off. Modern LS (and SBC) engines are fuel injected, so they have no problems adjusting to the altitude changes. More efficient, better emissions (usually.)

I have noticed that the boards have gotten a little stale with the current political climate, so I wanted to bring a new topic that is a little different.

9

Would be fun to follow along with you on here if you decide to do it. Lately I’ve been hooked on Tom’s Turbo Garage youtube channel. Right now he’s putting a turbo charged LS in a Toyota Tacoma. The project that got me hooked on his channel was his LS3 V8 Mazda Miata.

10

I was about to ask, ‘What is an LS conversion?’ Apparently, there’s a GM engine series known as the LS, and the conversion is putting one of those in place of the stock engine.

11

A lot of people are doing that because they get fuel injection and all of the modern niceties of a computer controlled car. Like just get in the car and start and go, don’t warm it up, don’t fiddle with the choke, that kinda stuff. But in that cool old car… or in my case, a lumber getter.