LS swap?

[86c10]

I've been hanging around this site for a while now and have been impressed with the amount of knowledge there is here. I'm just kicking around the idea of an LS swap into my 86 c-10 deluxe. It's never going to be a show truck, just a decent work truck for running to lowe's/home depot, hauling wood etc. I'm leaning toward the 4.8, I had one in a 99' 1500 4x4 that I put 100k on and had no problems with. My goal is to try and get mid 20mpgs out of the truck. The truck is all stock 305/th350 2.73 10bolt, with the exception of the custom home made open element air cleaner and single 2" straight pipe (you know your jealous).The 305 runs good but could use a rebuild on the q-jet, I've already done plugs and a fuel filter but not wires,cap or rotor. I think I'm getting around 10-12mpgs or so as it is. I have a 12 bolt with either 3.73's or 3.42's and a 2.5" dual exhaust that is left from a parts truck I bought. I can pick up a 4.8 with trans, ecu,harness and accessories for $1000-$1100. I'm fairly confident that I can sort out the wiring but I know I'll have to get someone to reprogram the ecu. I figure the whole swap would run me around $2000, is that realistic? I'm cheap with a very tight budget(whatever I can scrape up at the end of the month).What combination would get me closest to mid 20 mpgs for the best price? Is mid 20mpgs even possible with any combination, short of a diesel swap?
1)4.8/4l60e and 2.73
2)4.8/4l60e and 3.42
3)4.8/th350 and 2.73
4)4.8/th350 and 3.42
5)or work with the 305

This project is still a long way down the road, were in the middle of a renovation on our house.
Sorry for the long post.

Thanks in advance for any input.

[bake74]

      4.8/4l60e with 2.73 is best for gas mileage.  I don't know about the power range if the 3.42 would be better with the smaller 4.8.  There is a formula that you can find out what your rpm will be at what given mph with your gear ratios.    http://www.ringpinion.com/Calculators.aspx    Here is where you can find some of them.

[79ls1]

i did a ls1 swap a few years back in my 79 silverado , i put a posi 3.23? somewhere in that range and i get around 20 to 22 mpg but i do drive it like i stole it.  2000 dollars will prob be pretty hard to do. s&p helped out alot with parts and info. and comp. programming.

[86c10]

79ls1

i did a ls1 swap a few years back in my 79 silverado , i put a posi 3.23? somewhere in that range and i get around 20 to 22 mpg but i do drive it like i stole it.  2000 dollars will prob be pretty hard to do. s&p helped out alot with parts and info. and comp. programming.

 How much trouble was the fuel system? What did you do for your harness?

[Captkaos]

20-25 is defintiely possible with a LS, 3.42 gears should be fine.  If course a EFI'd 305 will get the same mileage, just not the power.
$2000 isn't going to cover all of it, I would assume $3000 and hope you can fall under it.
For the fuel system you need new fuel lines/hoses as you need a real return and feed line, and you need a 1987 sending unit with built in pump.

[86c10]

Captkaos

20-25 is defintiely possible with a LS, 3.42 gears should be fine.  If course a EFI'd 305 will get the same mileage, just not the power.
$2000 isn't going to cover all of it, I would assume $3000 and hope you can fall under it.
For the fuel system you need new fuel lines/hoses as you need a real return and feed line, and you need a 1987 sending unit with built in pump.

Thanks for the info. I've thought about putting on a TBI, but I wasn't sure if I could get the mileage I want. The 305 has enough power for the most part. I'm just hoping to get the mileage up to the point where I can drive it to work regular basis. I've been driving a 99' prizim for the last 5 years and only use my truck when I have to, I miss having a fullsize daily driver. The prizim gets 28-32 mpg which makes 10-12 mpg hard to justify on a 60 mile per day round trip.

[roadrage41]

shoot for 3000, plan for 4000.

these are still the cheapest things to swap a gen 3 motor into by far.

[Captkaos]

You won't pull 20 out of city driving, I am talking highway.  You can get 17 city out of the TBI 305, but the LS 4.8 would probably stretch that to 20.

At a point, you could pickup a 4.8L around here for about $350-400.

[79ls1]

fuel system wasnt a prob. you will need an 87 fuel injection sender and adapt the later model fuel pump. my ls was a 98 so it had no return but i just had to use the fuel filter for the 98 camaro it had the built in return and regulator. i used a painless harness but there are several diff options around today

[86c10]

shoot for 3000, plan for 4000.

these are still the cheapest things to swap a gen 3 motor into by far.

Can anyone give me an idea on where the $3000-$4000 might be spent? From what I've read $50-$100 for motor mount adapters, $150-$350 for ecu programing, the wiring I would do myself, I'm not planning on running headers. The wrecker that I would be getting drivetrain from said they would include all accessories,harness,ecu, manifolds,ypipe with cats and it would be a truck LS. I'm sure there are other details that I'm over looking as far as the cost is concerned.

You won't pull 20 out of city driving, I am talking highway.  You can get 17 city out of the TBI 305, but the LS 4.8 would probably stretch that to 20.

Most of my driving is higway, 55-65 mph, so the 17 range in town would be fine.

fuel system wasnt a prob. you will need an 87 fuel injection sender and adapt the later model fuel pump. my ls was a 98 so it had no return but i just had to use the fuel filter for the 98 camaro it had the built in return and regulator. i used a painless harness but there are several diff options around today

What size LS did you use, was it worth the hassel and cost?


   

[roadrage41]

Figure another 250-300ish for the fuel system, i don't know where you live but if smog isn't an issue, you won't need the cats.
2 new O2 sensors and a new maf is roughly another 2-300, we replace them in all of our swaps, and highly recommend it for d-i-y guys, those are the 3 main sensors your engine deals with, having one be bad will have you chasing down who knows what, finding out it was just a bad O2 will make you angry.
same way with the wiring harness, we dont use factory ones, they're hideous for one, and a single nicked wire when the engine was pulled can screw up a whole lot of things, and again, you will be angry.

after that, new plugs and wires are pretty much a given, trans cooler?, radiator? possible tranny flush and filter change? electric fans? possibility's are endless.



 

[79ls1]

myls1 is out of a 98 camaro, it was a little work not too bad ,yes it was worth it fun to drive and people surprised to see it when i open up the hood.

shoot for 3000, plan for 4000.

these are still the cheapest things to swap a gen 3 motor into by far.

Can anyone give me an idea on where the $3000-$4000 might be spent? From what I've read $50-$100 for motor mount adapters, $150-$350 for ecu programing, the wiring I would do myself, I'm not planning on running headers. The wrecker that I would be getting drivetrain from said they would include all accessories,harness,ecu, manifolds,ypipe with cats and it would be a truck LS. I'm sure there are other details that I'm over looking as far as the cost is concerned.

You won't pull 20 out of city driving, I am talking highway.  You can get 17 city out of the TBI 305, but the LS 4.8 would probably stretch that to 20.

Most of my driving is higway, 55-65 mph, so the 17 range in town would be fine.

fuel system wasnt a prob. you will need an 87 fuel injection sender and adapt the later model fuel pump. my ls was a 98 so it had no return but i just had to use the fuel filter for the 98 camaro it had the built in return and regulator. i used a painless harness but there are several diff options around today

What size LS did you use, was it worth the hassel and cost?


   

[86c10]

Thanks for all of the info guys. I'm thinking that a TBI swap might be easier and cheaper for now. Mileage and cost are my biggest concerns so spending $3000-$4000 to gain 10 mpg or so isn't something I can do any time soon. I can find 88-95 Chevy trucks for $400-$600 and part out what I don't need after I'm done. Any advice on the TBI swap. I know they aren't everybody first choice. I was think that I would get an adapter for the throttle body so I can use my stock intake and not get stuck having to use the TBI heads. I've read that hooking up the EGR can be a pain, I don't have emissions to worry about so if it doesn't need to be used i can leave it off.

[roadrage41]

I'd honestly start with the transmission, maybe a gear change. you'll see a bigger jump in fuel economy from having overdrive to bring down the cruising rpm's.

[86c10]

What do you recomend for a gear change? I've got a th350 with a 2.73 gear.