i get over 13 mpg all the time.

its awesome!

 

I'll tell you my experience for what it's worth; keep in mind that I'm in my upper 50's age-wise 'cause I'm sure that matters. By the way, my previous truck was a 4.3L ZR2.

First off, I'm confident that the stock 4.8 will perform better across the board than the 4.3 motor. No question and you'll get better mileage as well.

Fairly recently, I replaced my 4.8 with a 370 (sidenote: DAMN AM I HAPPY!). The 4.8 had a very mild Lunati cam because I wanted to increase the torque also. I had basically the same mods that I have now (LTs, tune, CAI, etc), just 77 fewer cubes. My mileage was 15-16 city and 21-22 highway and I had as much fun with it as I could.

Because I had to have a shop do my cam install, I ended up feeling like it really wasn't worth what I had in it $$$-wise. A slightly larger cam and a real cheap install would have made me feel different, I'm sure.

Replacing the 4.8 was my plan all along; the 293 performed well for me but I wanted more torque than it could produce. When I hit 150,000 miles I decided that the best move for me was the motor built for me by another board member, 67SS509 (thanks again, James, you did a helluva job! ).

Bottom line, if money IS an object, a good tune will be your best investment because it can improve your performance and your MPG over stock and, if you get a tune that includes updates, you can have it adjusted as you begin with your mods. Unless you can do (and undo) the work yourself, I'd hold off on the TC; from what you say about your plans and all, I don't think you'd like a high-stall converter. That's just my opinion based on what you've said here. Hope this helps!

 

Wow you fellas are awsome thanks a bunch for the help here. got the truck today after work, what a beaut! drinks all 'round PAID twice what i was hoping to on the down payment but i got my month bills down to under $240 per mo for the truck. not bad i dont think for it, only 42k miles and not a single scratch.

initial thoughts; whoa. GMC sure did hammer the nail on the head this go around.

I still am lookin to do a bit of internal work to this 4.8 to get it to better mpg and truck tq. on the ride home from the dealership i called comp cams tech line and spoke to a pretty good fella about a cam and spring package he has me grinnin about, except i want all yer guys opinion first. i told the guy, Jake, that i wanted a truck cam with some pretty good torque for a stock motor becuse i told him i couldnt touch the motor at all - like raise compression or nothing fancy, but i didnt mind a kind of rough idle but he said i could have it tuned to idle real nice like.

he email me the cam card for a custom grind cam he thought would work out perfect he said.

edit; copy paste the whole thing didn't work out so well.

here i will just list them out
Advertised Duration: 258 intake, 264 exhaust
Duration @ .050" Lift: 206 intake, 212 exhaust
Valve Lift with stock 1.7 ratio rockers: 0.545" intake, 0.552" exhaust
Lobe Separation angle: 110 +2
Intake Center line: 108
IVO:21
IVC:57
EVO:64
EVC:20

He said that was as far as the stock head could be go for real tq gains. i just hope i copyd it all right, im not to good with computers

 

I would also look into the comp 212/218 many members run that here and have had good gains. Me personally want to go for the LS6 cam 2001/2002 its pretty mild and will work with what I got oh yeah it idles stockish... if thats a word LOL

 

anyone have other thoughts about that custom grind cam ? just wonderin becuase i called back Jake at comp cams an asked him bout that 212/218 cam ya mentioned to me sharky05 cuz your not the first to recomend it, and he said it would blead off more cyl pressure compare to the custom grind he thought up for me.

 

You getting a custom tune before or after or at all?

 

tune no matter what

If i dont get a cam, ill have it tuned. if i get a cam, ill have it tuned. you fellas have expressed the importantce of how much a tune helps so thats on the list for sure.

 

Good deal, there are several board sponsers that can take care of your tuning needs...

 

that friend i told ya about earlier tunes his own f-body car pretty good, so ill have him do my tuning. hes pretty good at what he does

any opinion on the custom cam card Jake email me?

 

You are getting a full-size truck with the smallest V8, and you want to get the best mileage out of it? So the first thing you do is put heavier wheels on, throw in a cam, converter, etc.

Well, ok.....

If you really want to get better fuel economy, you might try to figure out a way to adapt VVT, AFM, increase the static compression ratio, and reduce pumping losses. Swap in a 6speed auto and less gear would definitely help. Good luck with all that on an 02 4.8L.

Put a bed cover on, smaller side mirrors if you want, lower it, add a lower front airdam, swap to hard, narrow tires on lightweight wheels, and take out weight. That all is easy to do and it will help your mileage.