Engine Swap Advice

[Cruck]

I do not know if this is the forum for this but I am hoping someone here will be able to help me.

I have a 77 C10 that I want to get up and running. It originally had a 6 cylinder and currently has a 350 that was put in sometime during the late 80s or early 90s. While that is a great engine the gas mileage on it is horrible. When asking for options I am told to either go with a 350/383 stroker or a 5.3 LS swap. All great options but I am not concerned about speed or power. I will not drive it daily nor will it be used to tow or haul things. I just want it to start up and go when while getting reasonable gas mileage.

GM makes a few 6 cylinder engines and I am wondering if any of them will work in my application. The Colorado and Camaro come with a modern 6 cylinder that gets 20+ mpg with over 300 hp. This is more than enough for what I need. Is there a legit reason why I could not use one of these engines? Can someone please give me some good insight on this? I have been told many times so form of no one gets a C10 to worry about gas mileage. If it is not a reasonable option then I have no other choice but a V8.

My understanding of cars is very limited and thanks for the help.

 

[ls1mike]

You are talking the 3.6, some are good some are not. I would skip it. For the amount of money and time it would take the 5.3 is be going to better and there is TONS of information about that swap out there. The 350/383 is still going to give you iffy MPGs.

 

[spasm3]

What rear end ratio is in the truck?

 

[Cruck]

Yes, I am talking about the 3.6. Assuming I go with the 5.3, how or is there a way to accomplish this while getting decent gas mileage?

 

[Cruck]

What rear end ratio is in the truck?

Not sure what you mean by that.

 

[skyactiv]

How many miles annually do you drive your truck?

 

[Cruck]

I want to say 5000 miles a year on it but more realistic would be 2 or 3k.

 

[ls1mike]

Not sure what you mean by that.

Like. 3.08, 3.42, 3.73, 4.10 etc

 

[skyactiv]

I want to say 5000 miles a year on it but more realistic would be 2 or 3k.

Stick with a 350. You'll never come close to recouping the money doing a LS or some odd V6 swap.

 

[slacktide_bitog]

Get the 5.3 LS

 

[Cruck]

Like. 3.08, 3.42, 3.73, 4.10 etc

As far as I know it is what it was at stock. If it has been changed I do not know.

Stick with a 350. You'll never come close to recouping the money doing a LS or some odd V6 swap.

The labor cost to do the swap will be minimal. I will mainly only have to pay for parts. Does that change anything?

 

[eljefino]

You'd probably get your best bang for your buck replacing the trans with a 4 speed, 700R4. You can even get TCC lockup without a computer if you get some canadian parts, in particular, a thingamabob that measures engine vacuum and allows it under partial throttle only.

GM put the 4.3 V6 in square bodies in 1987 with fuel injection, this sounds like about what you want, but why not get a whole truck set up like that? They aren't worth much.

You'll be pushing a square brick through the air with whatever powertrain you choose, the best way to save gas will be to go slower... things really get worse above 40 or 45, and don't preach to me about "pumping losses." Ride a motorcycle, keep yourself upright, the wind is a factor.

 

[TheLastWord]

I assume your current engine is carbureted? Any newer engine type would be FI (fuel injected). You do realize that would entail considerate mods and expense?

Given the few miles driven, it is not worth it.

2 - 3K per year? Do the math $$$

 

[fdcg27]

If it makes you feel any better, the 250 CID inline six of the time was no better on fuel and was even slower in use.

 

[spasm3]

If you are planing an engine swap for fuel mileage, yet only drive 2-3k a year, its not worth it. If you wanted the reliability, drive-ability and better fuel mileage and were into these sorts of projects yes if you do some work yourself. If it's paying someone else to do all of it, i don't see it being worth it at all.

I do think an ls engine drivetrain would be nice, having overdrive, but you would need to assess the rear end. A 3.73:1 or 3:42 would be what i would want for a daily driver.

 

[eljefino]

Also there may be differences between a "hot" 350 and a "mild" one... do you have 2 bbl or 4 bbl carb? The 4 bbl might be on something of a built motor with camshaft differences that waste gas.

My FIL had a 1980 1/2 ton that originally came with the 250 and, IIRC, 3.50 rear gears. He put an older chev 307 in due to the 6 getting old and wheezy. That perked the truck up and worked very well with the existing trans and rear end.

 

[Cruck]

You'd probably get your best bang for your buck replacing the trans with a 4 speed, 700R4. You can even get TCC lockup without a computer if you get some canadian parts, in particular, a thingamabob that measures engine vacuum and allows it under partial throttle only.

GM put the 4.3 V6 in square bodies in 1987 with fuel injection, this sounds like about what you want, but why not get a whole truck set up like that? They aren't worth much.

You'll be pushing a square brick through the air with whatever powertrain you choose, the best way to save gas will be to go slower... things really get worse above 40 or 45, and don't preach to me about "pumping losses." Ride a motorcycle, keep yourself upright, the wind is a factor.

This is my dad's old truck that I am trying to get back on the road. Otherwise I would just buy anything. I will only drive it when I am at home a few times a year. He will drive it from time to time that is it.

HAHA... I need to go faster than 45. It is 60 miles to the nearest walmart, lowes, starbucks etc. When I leave town it is all highway I want it get it to speed it just doesn't have to break any records getting there.

I assume your current engine is carbureted? Any newer engine type would be FI (fuel injected). You do realize that would entail considerate mods and expense?

Given the few miles driven, it is not worth it.

2 - 3K per year? Do the math $$$

Yes it is carb. If I go with a 5.3 it should cost about $6-8k. That is engine and supplies. More than half of that is the cost of engine. Correct?

 

[Cruck]

If you are planing an engine swap for fuel mileage, yet only drive 2-3k a year, its not worth it. If you wanted the reliability, drive-ability and better fuel mileage and were into these sorts of projects yes if you do some work yourself. If it's paying someone else to do all of it, i don't see it being worth it at all.

I do think an ls engine drivetrain would be nice, having overdrive, but you would need to assess the rear end. A 3.73:1 or 3:42 would be what i would want for a daily driver.

That is it reliable and driveable is what I am looking for. The work will be done for the cost of the parts only.

 

[LenZee]

Yes, I am talking about the 3.6. Assuming I go with the 5.3, how or is there a way to accomplish this while getting decent gas mileage?

Overkill has some knowledge about the 3.6

 

[bullwinkle]

This is my dad's old truck that I am trying to get back on the road. Otherwise I would just buy anything. I will only drive it when I am at home a few times a year. He will drive it from time to time that is it.

HAHA... I need to go faster than 45. It is 60 miles to the nearest walmart, lowes, starbucks etc. When I leave town it is all highway I want it get it to speed it just doesn't have to break any records getting there.

Yes it is carb. If I go with a 5.3 it should cost about $6-8k. That is engine and supplies. More than half of that is the cost of engine. Correct?

If you could find a wrecked one you could likely use the PCM, harness, even the transmission (like a 4L60E) and pick up a bunch of highway MPGs. That would be the cheapest way to do it, if you want to keep the old square body going. Those all disintegrated due to rust here many years ago...