91 full-size chevy help

[biggygomez]

ok i have a 91 full size chevy with a small block 350 and a 4 speed automatic.
selling it isnt a option and it gets better as mileage than any of these back woods rednecks say is possible. 25 mpg but i know there is more in it. so far all ive done is open up the exhaust,intake and putt it on a diet

[aardvarcus]

Hello, I also have a 1991 Chevy Pickup with a rebuilt 350, 700R4, and 4x4. Is yours two or four wheel drive? You are already doing pretty good at 25 MPG, mine doesn’t get anywhere near that. Could you provide us some more details on what exactly you have done to the intake and exhaust and what you have removed as a part of the truck’s diet? If you haven’t already, routine maintenance is a good place to start, changing fluids and filters helps with efficiency and longevity.

Some low hanging fruit would be aerodynamics. Attacking the truck bed will be the easiest for the best return, to start you can do a bedcover. I don’t know what your budget it, but you can find cheap used bedcovers or even make a half bed cover out of one sheet of osb, just put it on the back half of the bed.

If yours has the recessed bucket sealed beam lights like mine, I would suggest making a heat formed lexan cover (or swapping for the non-recessed front clip). A front air dam will help as well, think of lawn edging below your front bumper to send the air around your truck, not under. You don’t need to go super low with it, just low enough to be below most of your underbody. You can also consider a partial grill block, especially during winter; just keep an eye on your temperatures (and have a way to remove it if needed).

Another big aid would be removing the engine driven fan and replacing it with a temperature controlled electric fan(s). You can get your fans from a junkyard.

This may be beyond where you want to go, but my truck had many 700R4 issues and is destined for a manual swap. I have a NV4500 waiting to go in.

[biggygomez]

mine is two whee drive 700r4 with a manual valve body, Corvette servo and converter lockup kit in 2,3,4 dual cold ram air intake and true dual 3"exhaust as for the diet removed ac tool boxes swapped in aluminium race seat
i know this set up is more of a race setup but this truck was a toy that i know use as a daily driver. im building a full bed cover to night

[biggygomez]

almost done with bed cover next project is a big rig bumper that I've had in my garage looking to do something like nascar truck style with a spliter
unfortunately i cant block the grill because the area on the core support is were my ram air ducts are

[ksa8907]

That's pretty impressive! Do you track your mileage on paper or an app? Welcome to ecomodder.

[biggygomez]

i do the math on my phone but to be fair i only keep track of my mileage when im not out playing with kids taking there lunch money .

and i know that racing is dangerous before i get shoot we us a closed course

[aardvarcus]

On the exhaust did you retain EGR port in the headers? Also, on your dual ram air intake, where do the two tubes join together? Do you have any estimates of the weight of the items you removed, particularly the AC and seat? Sorry for all the questions.

I am looking forward to seeing what you do with your big rig bumper; I am assuming it is one of those tall aluminum ones.

[cRiPpLe_rOoStEr]

Have you never considered to get a supercharger? It might initially not sound so straightforward mileage-wise, but combined to a cam with a longer intake valve timing and a raised compression ratio it can provide some nice improvements.

[biggygomez]

my truck didnt have a egr ac and seats were about 50 the boxes were 500+
the intake is a factory with a second air inlet welded to it and the bumper is a molded plastic bumper off a more modern rig rounded with a steped chin

whats your truck running

[biggygomez]

ive been trying to sell my gf on one for years but she says if i put any more power in my truck it will kill me probably because shes seen my truck race

but i like the concept more power needs less work to get down the road