400 rwhp and 20+ mpg?

[68shortwide]

Originally Posted by Grumpy old man

Good ,this is the place to learn and get help ,Now lets see what truck your starting with .

Can't upload pics from my phone unless its a fb message so.....kinda stuck there

[MARKDTN]

Originally Posted by 1972BlueC20

I have a 72 C20 with 350 and TH350 trans......I'm running an edeljunk carb.....I'm getting 10-11 mpg 95% city driving only with short driving distances.

I was a bit disappointed at first, but then I remember my 99 tahoe got about 12-16, and my 2010 GMC truck got 13-17 so it's really not bad for a 42 year old non-fuel injected brick rolling down the road...

I'm calling BS on anyone that is claiming they are getting more than 15 or 16 MPG with a stock configuration 67-72 truck with city driving....im not saying it's impossible but very hard to achieve.

I have an '83 K20. I swapped the original anemic 350 for a Tuned-Port 350 from a '90 Corvette w/ aluminum heads. It has 3.42 gears and a 700R4. I have had it since it had 42K miles. It always got 14 city and 17 highway. With only a change to TPI, I went to closer to 17 city and 20 highway (empty). Now I "only" have 300 or so horsepower, but the TPI has a lot of bottom-end torque. It feels so much better loaded on the hills.

[Turbo1dr]

My 600 RWHP 78 Malibu has gotten 26 on the highway at 70mph. This is with a 200-4R and a 3.42 rear end. It's a turbocharged Buick V6. I would probably go with a stock cammed 4.8 or 5.3 and add a turbo/intercooler for an easy 600 at the rear wheels. Don't go overboard with a cam and that combo should get at least 20 on the highway in these trucks if you keep the gear ratio around 3.42.

[Grumpy old man]

Originally Posted by Turbo1dr

My 600 RWHP 78 Malibu has gotten 26 on the highway at 70mph. It's a turbocharged Buick V6. I would probably go with a stock cammed 4.8 or 5.3 and add a turbo/intercooler for an easy 600 at the rear wheels. Don't go overboard with a cam and that combo should get at least 20 on the highway in these trucks.

I have a couple Harley's that run 80 all day long and pull 35 mpg Doesn't mean a whole lot when we're talking '67-72 Trucks !

[Turbo1dr]

Originally Posted by Grumpy old man

I have a couple Harley's that run 80 all day long and pull 35 mpg Doesn't mean a whole lot when we're talking '67-72 Trucks !

That sucks when a VW Jetta diesel can do the same thing...lol. However, the Harley would take the *coolness* factor.

[HEADTURNINGC10]

20 mpgs IS do-able with todays technology. The money needed is up high. "It costs to go fast how fast can you afford to go" we are talking about running 93 octane, electric cooling fans, electric water pump, aluminun vortec style heads (all those things just give a slight percentage increase it adds up though), electronic fuel injection kits (they claim 4-6 mpg gain), thats for the a small block style engines.
There are multiple ways to skin a cat though.
-4.3L is an option with turbos done right you should see good mpgs not driving like you stole it
-Or even a mild 5.3L (any LS style motor) conversion
-Youll need to look into a 6 speed manual transmission (t-56 trans is a good choice for that) but rear gears will need to be changed accordingly
The new epa laws kill mpgs on new vehicles.

But you wont be able to get higher 20 miles per gallon without computers and TUNED CORRECTLY

cant wait to see pics and to hear about this build

[Grumpy old man]

if you wanna play you have to pay ! Period , We can all complain about what it costs to feed the monster but only you can decide if it's worth the effort /time and expense if not buy a jetta and drive slow in the fast lane while texting !

[no1udknow]

you guys are missing the mark... the trick is torque, torque is where it's at. If you can increase torque, it takes less effort for the engine to turn larger wheels. By increasing wheel size, and you can cover more distance per revolution of the wheel. This means you need less revolutions to cover the same distance, which means you need less revolutions of the engine to cover the same distance. Less revs of the engine means less fuel used. This is why diesel trucks with bigger tires get descent gas mileage. My brother has a 05 dodge diesel with a fast fuel, edge juice, and 37's and on the highway he gets about 25mpg because the engine is running about 1800 rpm at 80mph

The torque can be achieved by increasing volumetric efficiency, or increasing stroke.

[Grumpy old man]

Yeah well .... that diesel will be watching my tail lights fade away with my 572 and Muncie fuel eating fire spitting leave you boys on the porch good ol chevy horse power at 5 miles to the gallon and a grin on my face all the way to the next fuel stop ! Go buy a prius and quit complaining about what real horse power cost ! Go big or go home ! ... if you have to worry about what it eats go small and stock ....hmmmm there is a 650 super charged chief motor out there ......20 gallon gas tank 40 gallon reserve sounds about right ,it's only money you will make more or you'll go 6 cylinder ? I heard Wizzer makes a good motor ?

[52napco]

Originally Posted by Grumpy old man

Yeah well .... that diesel will be watching my tail lights fade away with my 572 and Muncie fuel eating fire spitting leave you boys on the porch good ol chevy horse power at 5 miles to the gallon and a grin on my face all the way to the next fuel stop ! Go buy a prius and quit complaining about what real horse power cost ! Go big or go home ! ... if you have to worry about what it eats go small and stock ....hmmmm there is a 650 super charged chief motor out there ......20 gallon gas tank 40 gallon reserve sounds about right ,it's only money you will make more or you'll go 6 cylinder ?

I would love to catch you out on the street with my 27 mpg datsun

[Turbo1dr]

Originally Posted by Grumpy old man

Yeah well .... that diesel will be watching my tail lights fade away with my 572 and Muncie fuel eating fire spitting leave you boys on the porch good ol chevy horse power at 5 miles to the gallon and a grin on my face all the way to the next fuel stop ! Go buy a prius and quit complaining about what real horse power cost ! Go big or go home ! ... if you have to worry about what it eats go small and stock ....

You better watch out for those diesels....they can be very fast too. Bigger isn't always better like many old school guys think. I've tore up plenty of big block *pure race cars* at the drag strip with my air conditioned, power windowed, cruise control...etc 3500lb Malibu. It's sooo fun when a they find out a V6 done put a whooping on them and still drove home on the street! It sounds like a bumble bee but it WILL sting when provoked...haha.

[52napco]

Originally Posted by Grumpy old man

Yeah well .... that diesel will be watching my tail lights fade away with my 572 and Muncie fuel eating fire spitting leave you boys on the porch good ol chevy horse power at 5 miles to the gallon and a grin on my face all the way to the next fuel stop ! Go buy a prius and quit complaining about what real horse power cost ! Go big or go home ! ... if you have to worry about what it eats go small and stock ....hmmmm there is a 650 super charged chief motor out there ......20 gallon gas tank 40 gallon reserve sounds about right ,it's only money you will make more or you'll go 6 cylinder ?

I would love to catch you out on the street with my 27 mpg datsun

[Turbo1dr]

As someone else said, 400rwhp (500 at the crank) and 20mpg isn't going to happen with a carburetor and an *old school* small or big block chevy engine.

[Grumpy old man]

Originally Posted by 52napco

I would love to catch you out on the street with my 27 mpg datsun

To do what haul extra gas when I need it ?

[Grumpy old man]

Originally Posted by Turbo1dr

You better watch out for those diesels....they can be very fast too. Bigger isn't always better like many old school guys think. I've tore up plenty of big block *pure race cars* at the drag strip with my air conditioned, power windowed, cruise control...etc 3500lb Malibu. It's sooo fun when a they find out a V6 done put a whooping on them and still drove home on the street! It sounds like a bumble bee but it WILL sting when provoked...haha.

Let me know when your ready ! NOTHING beats a worked 572 with a good driver and a good suspension .

[Fitz]

Originally Posted by Grumpy old man

Yeah well .... that diesel will be watching my tail lights fade away with my 572 and Muncie fuel eating fire spitting leave you boys on the porch good ol chevy horse power at 5 miles to the gallon and a grin on my face all the way to the next fuel stop ! Go buy a prius and quit complaining about what real horse power cost ! Go big or go home ! ... if you have to worry about what it eats go small and stock ....hmmmm there is a 650 super charged chief motor out there ......20 gallon gas tank 40 gallon reserve sounds about right ,it's only money you will make more or you'll go 6 cylinder ? I heard Wizzer makes a good motor ?

Hey! I resemble that remark but I'll have you know a 572 will get 14 mpg at 70 on the freeway. The only caveat on that is you have to keep your foot out of it.

[mechanicalman]

Originally Posted by 1972BlueC20

I have a 72 C20 with 350 and TH350 trans......I'm running an edeljunk carb.....I'm getting 10-11 mpg 95% city driving only with short driving distances.

I was a bit disappointed at first, but then I remember my 99 tahoe got about 12-16, and my 2010 GMC truck got 13-17 so it's really not bad for a 42 year old non-fuel injected brick rolling down the road...

I'm calling BS on anyone that is claiming they are getting more than 15 or 16 MPG with a stock configuration 67-72 truck with city driving....im not saying it's impossible but very hard to achieve.

What is your compression ratio? What casting number heads are you running? Cam? You can really maximize your mileage if your ignition curve matches compression ratio, camshaft, cyl head design, cruise RPM, etc. Modern heads (vortec and other fast burn design) make a huge difference and make the distributor easier to tune as they don't need as much total advance, small chamber heads come in second and open chamber are the worst for mileage.

14101083 (can be standard or angled center holes) and 14096217 (angled center holes) are TPI heads and are actually fast burn design and are really good mileage getters. I saw a set at the U-pull-it last weekend.

You will never get as efficient timing curve on a non-computer engine as you will on computer controlled. If you had a computer controlled (ESC) distributor on your carbureted engine (properly tuned), you would likely get as good mileage as fuel injection if timing curve was equal.

Edeljunk? Not fair, sounds like your carb needs some love, and maybe your distributor as well.

[68shortwide]

After some thought I think what ill do is just run a carbd small block and say f*** mpg and just buy a 94-6 lt1 impala or ls Camaro for a dd

[gonnuts]

Originally Posted by 68shortwide

what's the best way to go about 400 hp to the tires and still get 20-30 mpg? Sbc or ls?

duramax!!

[52napco]

Originally Posted by Grumpy old man

Let me know when your ready ! NOTHING beats a worked 572 with a good driver and a good suspension .

Isn't english mountain dragway over by Newport ?? Let me know and I'll drive over there and meet you. I think they run on Friday evenings. Let me know when loser buys supper.

[Grumpy old man]

Originally Posted by 52napco

Isn't english mountain dragway over by Newport ?? Let me know and I'll drive over there and meet you. I think they run on Friday evenings. Let me know when loser buys supper.

I only eat steak and lobster bring lots of cash with you ! i've been self employed for 35+ years building muscle cars and trucks for customers ,Only big dogs sit on my porch ! I'll send my daughter to drive ,Careful she's quick on the lights but she's beautiful and that will make it easier for you to say "damn I got beat by a chick " Not a bad looking kid from a Grumpy old man ,Ehh?





http://

[Lees68GMC]

Not 400 RWHP but an honest 420 at the crank and cost effective upfront.

A Vortec 5.3 / 4L65E with Stock intrernals like out of a 2005 Suburban, with a HP Tuners file, K&N filter and good exhaust can easily make 415 HP with nothing more than a Cam change. 18+ around town 27 MP_G on the highway with 3:42 gears. About $1800.00 for the eng / trans combo, $200 for the Cam and you're in business reasonable smokin' Ford Lightning and Raptors and getting good mileage. You can get that with stock springs and a Cam change. I you want more (still reasonable priced) you have to go with Yellow Beehive springs and if you want more radical 500+ you gotta go roller rocker arms, titanium keepers > More money. Understand I'm talking "Reasonable budget when compared to a $6000.00 crate LS3 with no wiring, PCM, trans or accessories, in My opinion.

[BigRed76]

My '71 C10 has a 5.3/4L60E, 3.73's, 29" tires, only upgrades were headers and exhaust, no tune yet, and my best was 18.5 MPG and that was all interstate miles. Normal driving it still gets 17-18 anyways. I'm sure it could do better with different rear end gears and a tune.
It doesn't make 400 rwhp (yet ) or get 20 MPG, but it does about 5-6 MPG's better than that old 307 it had and will melt the tires off so I can't complain.

The only truck I could see realistically pulling off 400 rwhp and 20+ MPG is maybe a 4.8/5.3 in an S10...

[Lees68GMC]

It's probably all tune and gears my guess, it'll improve, you're over a Mile High where you live like me here. I'm running 3:42 gears, 15 X 8 wheels with 275-60-15 BFGs about 27" FYI I grew up in Wheat Ridge, I'm an Old Coot, Wheat Ridge High 1970.

[68shortwide]

Originally Posted by Grumpy old man

Good ,this is the place to learn and get help ,Now lets see what truck your starting with .

This is what im starting with. It's rough, but i think i can make it purdy again