Keep the 454 or go 350??

[Bagged Dually]

So while at my little brothers house last weekend he offered to trade me motors.His truck has a mildly built 350 and mine has the bone stock TBI 454 in it. I don't really pull anything to warrant needing the big block and I could use the extra mileage. My main question is what will we have to do to swap them over besides the obvious things like exhaust? How hard would it be to run TBI on the 350? If I put TBI on the 350 what kind of mileage increase should I expect to see?? Last but not least is my biggest concern....All of the accessories. Right now I have all of my factory stuff except smog. Will my accessories bolt up or will we have to trade those also??

 

[bucket]

You may gain 1 or 2 mpg in town, but on the open road your mpg will stay the same... and you will have an under-powered truck.

 

[skysurfer]

Sounds like a lot of trouble for almost no return. You're giving up torque for horsepower, not a good choice for a dually. A 350 will get your truck around, but your foot will be way into the throttle. I would be surprised if you saw more than a 2mpg gain from the swap. BBC,SBC...TBI's suck fuel.

 

[Bagged Dually]

So what I'm getting from all of this is to keep the 454 and dump the TBI??

 

[bucket]

So what I'm getting from all of this is to keep the 454 and dump the TBI??

Keep the 454, and the TBI too unless you go for some kind of multi-port setup. TBI is no worse mpg than a carb.

 

[Bagged Dually]

hmmm...Just time to start looking for an over drive transmission sounds like.

 

[HotRodPC]

Sounds like a lot of trouble for almost no return. You're giving up torque for horsepower, not a good choice for a dually. A 350 will get your truck around, but your foot will be way into the throttle. I would be surprised if you saw more than a 2mpg gain from the swap. BBC,SBC...TBI's suck fuel.

Being a dually, and you already have the core, and the truck is set up for it, I'd go with the 454. If it were standard cab, single wheel, 2wd, I might give more consideration to a 350, but I think in that heavy truck, and what it can do, I'd go for the low hp torque monster. With some head replacement, or work, you can even get some hp out of it too.

 

[Bagged Dually]

I was just looking at the 350 for any increased mileage I might pick up. I'm in no illusion that I'll ever get good mileage and that's why I don't drive my truck daily. It sounds like I'll be much better off to just do what I can to improve the mileage of the set up I already have. I think I'll just try to make mine breath a little better and hunt down some kind of Over drive option whether it may be an add on unit or a new trans. Some different rear end gears might be in my near future also. It's hard to justify 4:11's when all I do with my truck is drag it around town.

 

[oneluckypops]

will have to dis agree. My 96 has 4.56 gears 4L80E with a 350, my MPG is averageing around 12-14.
My FIL has a 99 regular cab 2wd dually, again 4.56 gears and a 4l80e, with a 454 his mileage is terrable, he get 6-8 mpg. honestly I think my truck pulls better then his also. I can hook the trailer to my truck and take a drive, noticing how many times my truck downshifts, then hook the trailer to his truck, and drive the same route, his truck will downshift WAY MORE then mine.

FWI I am not a 454 fan, they are IMHO way over rated.

 

[davbell22602]

Stick with 454 since its a dually.

 

[skysurfer]

Modifications for fuel economy rarely return the investment unless your driving a crazy amount of miles. I would love to drop a Gear Vendors unit in my truck but I just don't drive it enough to recoup the expense. The only engine swap the op could do and see any serious mpg gains would be a Cummins, but he would have to be a full-time RV'er towing a 5th wheel to justify the cost.

I beat the high cost of fuel by buying a used economy car. It's not "cool" and women aren't clamoring to bear my children because of it, but if I drive it 30k miles the fuel I've saved will cover the purchase price.

 

[oneluckypops]

Stick with 454 since its a dually.

WTF does dual wheels have to do with it? Theres alot of trucks that have dual wheels that DONT have a big block in them around here.

 

[oneluckypops]

Modifications for fuel economy rarely return the investment unless your driving a crazy amount of miles. I would love to drop a Gear Vendors unit in my truck but I just don't drive it enough to recoup the expense. The only engine swap the op could do and see any serious mpg gains would be a Cummins, but he would have to be a full-time RV'er towing a 5th wheel to justify the cost.

I beat the high cost of fuel by buying a used economy car. It's not "cool" and women aren't clamoring to bear my children because of it, but if I drive it 30k miles the fuel I've saved will cover the purchase price.

I would agree with this one. only thing is he already stated he does NOT drive it everyday,

 

[bucket]

will have to dis agree. My 96 has 4.56 gears 4L80E with a 350, my MPG is averageing around 12-14.
My FIL has a 99 regular cab 2wd dually, again 4.56 gears and a 4l80e, with a 454 his mileage is terrable, he get 6-8 mpg. honestly I think my truck pulls better then his also. I can hook the trailer to my truck and take a drive, noticing how many times my truck downshifts, then hook the trailer to his truck, and drive the same route, his truck will downshift WAY MORE then mine.

FWI I am not a 454 fan, they are IMHO way over rated.

Two things. One, something is very wrong with his 454 truck. That's just not right. Two, you're kind of comparing apples to oranges. The difference between the vortec 350 and 454 is not as great as the TBI 350 and 454. Most vortec 350's are very peppy, but I don't need to tell you that.

 

[oneluckypops]

Two things. One, something is very wrong with his 454 truck. That's just not right. Two, you're kind of comparing apples to oranges. The difference between the vortec 350 and 454 is not as great as the TBI 350 and 454. Most vortec 350's are very peppy, but I don't need to tell you that.

no I think its apples to apples. His is a 99 454 (vortec)
Mine is a 96 350 (vortec)

ok well i do understand what your saying. the vortec 350's are alot better then the older ones which is why mine pulls better then his 454.

There could be something wrong with his truck i have never looked at it.