Can’t decide on single or dual tanks

[SquareRoot]

Y'all haven't mentioned the great equalizer....turbo. Smaller engine + boost=larger engine w/o boost plus economy. My neighbors Raptor V6 turbo is amazing.

 

[boltbrain]

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Apples to Apples a 5.7 small block with modern engine management. A 5.3 ls and a 6.0 ls with modern engine management.

Thanks, not quite. I’ve been talking about 4x4 2500. this is the site that I sourced to get the specs for a 02 2500 4x4 with a 6.0 I saw on Craigslist. That was listed at 11 mpg highway.

 

[Grit dog]

Well now that we’ve left fuel tanks and moved on to engines. (That part is easy on these trucks. Can buy everything needed at reasonable prices for whatever OE style setup you want. No reason to try to over engineer in this area. Especially since you have a flatbed so fuel filler is easy in about any location.)

If you’re hoping to recoup the cost of a LS swap in fuel savings, ain’t gonna happen. Not even close. Especially if you’re keeping a non OD trans (more $ and time to swap that).
But turning a 40 + year old truck into anything that resembles an efficient comfortable high miles daily driver is not going to be cheap. It can be reasonable if you start with the right vehicle, like @SirRobyn0, you can get there. But HP costs $. Period. And he would have spent a lot more by now if he was pushing more power than a stock 80s small block produces. And he fell into a reliable truck with OD for cheap.
I can tell you an early 5.3/4L60 4wd Tahoe is 13-14mpg all the time. Main duty is 50-60 mi commutes mostly highway. Sometimes stop n go sometimes 85mph. Straight 80mph highway = 13 mpg. About the same weight as an old square. But it probably has 3.42 gears.
Speed makes a huge difference though. What speed is your mpg at?
Not 80-90mph presumably.

 

[SirRobyn0]

Well now that we’ve left fuel tanks and moved on to engines. (That part is easy on these trucks. Can buy everything needed at reasonable prices for whatever OE style setup you want. No reason to try to over engineer in this area. Especially since you have a flatbed so fuel filler is easy in about any location.)

If you’re hoping to recoup the cost of a LS swap in fuel savings, ain’t gonna happen. Not even close. Especially if you’re keeping a non OD trans (more $ and time to swap that).
But turning a 40 + year old truck into anything that resembles an efficient comfortable high miles daily driver is not going to be cheap. It can be reasonable if you start with the right vehicle, like @SirRobyn0, you can get there. But HP costs $. Period. And he would have spent a lot more by now if he was pushing more power than a stock 80s small block produces. And he fell into a reliable truck with OD for cheap.
I can tell you an early 5.3/4L60 4wd Tahoe is 13-14mpg all the time. Main duty is 50-60 mi commutes mostly highway. Sometimes stop n go sometimes 85mph. Straight 80mph highway = 13 mpg. About the same weight as an old square. But it probably has 3.42 gears.
Speed makes a huge difference though. What speed is your mpg at?
Not 80-90mph presumably.

Your spot on with the comments about my truck.

I never intended it to be my daily driver, it was suppose to just be the farm work truck only hitting the road for feed hauls. IMO an LS swap isn't practical. Sure you'll have more power and get a little better gas mileage but. I'm going to be frank and I'm not picking on anyone, but I just don't understand why someone would by an old truck and swap it to an LS. If I wanted an LS truck, I'd buy a truck that came with an LS factory. I really don't get it.

Sure my 305 is no power house. But with overdrive I can squeeze 16mpg empty on the highway if I keep the speed around 60mph which I'm not very good at. More often I'm at 70+ to keep up with traffic them we are talking more around 14MPG.

BUT I didn't have to pay for an LS swap nor did I have to do the weeks worth of work to make the conversion. The carb is tuned right and fires with one pump every time and runs and drives just like it should. And it is a pleasure to drive, for me.

My point to all this is that the old stock power train can make a daily driver and IMO I think a person is far better off the invest in the old stuff that to try to modernize. BUT I'm jaded. I'm an auto mechanic and work on modern vehicles all the time to make a living. No way helll I want to have to work on that on my own vehicle. Some folks seem to think LS swap in these trucks is the end all to be all engine swap but I'm not feeling it.

IF I had my choice I'd probably want factory injected vortec engine, but only if squares had come that way from the factory which they did not.

When you sit down and add up all the details and costs involved in swapping engines you'll be blown away. You'll never recover the cost in fuel.

And yes I'm ok with going slow up hills when I'm towing. My little carb'ed 305 has done everything I've ever asked it to and it does good on gas for what it is and I'm happy with that.

So there's my take on engine swaps.

 

[Grit dog]

^Just like I hate home improvement projects after 30 years of construction….lol!
OTOH, I’d do a LS or a Cummins swap in a heartbeat. Sounds cool to me.

 

[SirRobyn0]

^Just like I hate home improvement projects after 30 years of construction….lol!
OTOH, I’d do a LS or a Cummins swap in a heartbeat. Sounds cool to me.

Hey, everyone has their own feelings on engine swaps and I try not to disparage those that want to or have swapped just because I'm not into it.

However have no love for diesels.

IDK, if I have really ever told this story on the forum and I might just get shot for telling it.

Right before I got the square, I knew I needed a bigger truck, and I needed a bigger trailer. I was just kind of starting to look a little and the plan was a 1990 - 2003 Ram 2500 or 3500 I wanted the 8.0L if I could find a V10 truck that wasn't hammered. Remember my plan was not to be dailying my larger truck. Then I heard about my friends passing, and you know the rest of the story I'm sure.

The most wild thing I do would a swap to a 350 lol. A 454 would nice, but at this point I don't think that would work. Besides the increase in fuel use, I just rebuilt the 700R4 and while we did do some upgrades to it I'm not sure I'd really wanna put it behind a BB. Hopefully I can get at least another year out of the 305. My 96 GC is going to get a transmission just after the first of the year, so between the to trannys I'm really hoping not to have anymore pricey car repairs for at least a year.

 

[boltbrain]

This is all great info, very helpful. I do know one guy who put a LS in a 83 and he pretty much agrees it’s not so much for mileage or power but just for the added reliability and to extend the life of a good old simple truck. The 350s are getting old. Some guys just hate to scrap them. I really like my NP205 and SM 465. So am considering a overdrive from Gear Vendors. It’s pricey but they have a reputation for reliability and labor is nothing. Shorten the driveshaft.
Well I may start another thread for this but I need an electric inline pump and don’t know which brand. Want reliability. So will do a search. The threads on the new mechanical pump seem fine, the nut tightens into it fine, but it keeps leaking and it a real SOB changing that thing out. .