79 Chevy C20 build. keep carb or swap EFI?

[Anti Bling]

I'm building my 2wd 79 C20 Chevy.









I was using it to haul my quad out to the sand dunes and desert of southern Nevada and California. I am adapting the purpose of the truck over to a camping rig. that will pull a trailer for two quads/chuck wagon that has yet to be built. i have a fiberglass camper shell with a lumber rack on it ready to go on. the tire rack and fuel jug rack in the bed have been pulled in anticipation of the shell install. this is a weekend/seasonal toy so if it is torn down for a bit that is ok with me. smog laws for this truck are somewhat lax here in So. Nevada. as long as it passes the sniffer test thats cool. If i can pass the sniff test with the motor thats in it just fine, i bet i can get just about any EFI motor to pass.

plans are in the works to convert it over to 4wd in the future. but until then, I am in the search for better fuel economy. those 33's on 20 inch wheels are gone now as they weighed a TON and were starting to separate! i have 32 inch tires on stock 16 inch wheels but i will be upgrading to late model HD 16 inch aluminum wheels soon. the front suspension has fabtech lift springs and ball joint spacers. the ride is a bit rough, but the dual batteries up front softened it up a bit. adding a new front bumper and a winch should soften it up even more.
the rebuilt 350 v8 has a edelbrock intake manifold and 600cfm carb, MSD HEI and an unknown RV camshaft. it pulls down about 11 mpg @70MPH. the FF 14bt has 3.73 gears behind a 3 speed manual gearbox with granny low gear. i would love to get better MPGs so the dual fuel tanks will provide better range.

i question i have is...... would swapping in a EFI set up get me longer range/better MPGs? or should i swap in a 5 speed when i convert to a 4wd set up? or both? any thoughts? i have decent torque/power as it sits so more power isn't a concern. i have the tools and talent to swap in a EFI but I'm concerned with the time and expense versus the benefits.

I'll be posting up my progress when time and funds permit.

 

[Vegasrandall]

I'm doing almost the same thing with a 77 g10 SWB Chevy van.I was told to get the TH700 4 speed auto tranny. I'm sticking with a quadrajet carb for easier maintenance. Good intakes and exhausts,tall gears and a light foot will do wonders for milage. I'm also keeping every possible bit of extra weight off the build figuring that every 7 pounds of weight eliminated gives you the equivalent of a horsepower.

 

[bftank]

i doubt that truck is going to consistently get better than 13 mpg with efi on that set up. i would put that money toward a rear locker or a 5 speed.

-make this your build thread!

it looks like you have some good build ideas. i like the way the truck looks with the front lifted and 33's. i would be tempted to leave it 2wd and get a detroit locker for the back.

-look for hummer h2 rims on craigslist, they are 17" aluminum and a set can usually be had for cheap. more tires available for 17" rims as well.

dig the prerunner vibe you have!

 

[Anti Bling]

i really am debating the 4X4 swap. a locker in the rear end will happen no matter what. i have 96 ford ranger that i use as a daily driver but it has a small 4 cyl motor, is gutless, and only gets 20mpg. if i could get better millage than 15-17 in the chevy i will sell the ranger and then put the money from the sale of the ranger and put it into the chevy build. having to drive from Las Vegas to Los Angeles every week for work better fuel mileage is quite important. but this ranger really is not filling its intended role. i thought that a 4 cyl truck would pull better MPGs than this.

i removed the 33x12.50-20 as they were starting to separate and were really heavy. there would be no way to get a spare wheel/tire onto the roof rack i am planning to build. the 20's looked ok. but really wasnt my style. i have the stock steel 16's on there with a tire that is close to a 32x8. i cant remember the exact size but its ok i guess. i was going to keep the tires i have now but get the factory 16 in aluminum HD wheels and maybe powder coat them. i think maybe a 5 speed swap would be the way to go. this 3 speed tranny with granny low isnt cutting it. its like i'm back in a big rig shifting a 21 speed.

BUILD UPDATE:

this weekend i ran the fuel lines to the aux fuel tank that i installed a few months ago. i never got around to hooking the dang thing up. now i have to wire up the gauge to a switch so i can toggle from one tank to another. the fuel transfer is being handled bye a manual bypass that was already mounted under the drivers seat. i haven't tried it yet to see if it works yet but I'll put some fuel in it this week and run it.

also i got my dual battery set up installed. i picked up a diesel aux battery tray out of a wrecking yard. and wired it up with 4ga. cable left over from my car audio day. i installed two yellow top batteries and now that started spins the motor like its on steroids. ill post pictures soon. its too dang out outside with these monsoon rains and 105+ temps i don't work outside all that much in the summer.

next on my list is to install my camper shell and remove the tire and fuel jug racks from the bed, build abed/ mattress platform and build a roof rack with swing out tarp awning. i plan on taking a bunch of pictures of the build if anyone is interested.

 

[ExpoMike]

Overdrive trans will net you the biggest MPG return. EFI is nice to get the last little bit you are likely going to but the benefit will be lower than an overdrive.

Nice truck BTW.

 

[Anti Bling]

i know that there isn't much to see here. but, I used a hole saw to gain a way to mount the filler to the bed side. the drivers side fuel tank came from a donor 77 Chevy 4x4 and is factory 20 gal. tank with skid plate. it was pulled from a running truck and had fresh fuel when pulled, so I'm not to worried about crud in the tank or bad gas. it was easy 20 min install because i grabbed everything that held the tank like bolts and brackets. the hardest part was trying to figure out where to drill the hole so everything lined up for the filler neck. the fuel line was routed to the selector valve and i also added another in line fuel filter. i got the filler neck hole drilled close but i don't like how vulnerable the fuel cap is. i want to make a recessed filler so the cap wont get damaged when out on a trail.



here is the start of my wiring/charging/breaker set up. i do not have the solenoid hooked up as of yet so it is mounted but not finished with the control circuit yet. there is a breaker on here in line so i trip the breaker so if there is a drain on the system this battery is isolated until i reset the breaker. so far it works like it should but i plan on wiring the solenoid up to an oil pressure switch on the motor so it kicks in when the motor is running. i will also install a switch to be able to self jump/draw off both batteries when needed. the box between the solenoid and the breaker is the HID ballast for my headlights. yes i have H4 headlights with 6500k HID retrofit bulbs in them. i like them. no glare like the Honda kids and their HID retrofits. but with this kit i loose the Hi-beam function. but that is fine with me because i have additional lights on my bumper.



another shot of drivers side battery.



pass side battery area. i have all of my lights on relays. so every function has a relay. for example: drivers side low beam=one relay, drivers side high beam(now not used)=one relay.
the small fuse panel is for the light functions. while the fuse panel was inexpensive, i do not like it much as the terminals and fuses are exposed to the elements. as soon as i find a better panel it will be upgraded.



the fuel tank selector valve that was in the truck when i got it. it is just in front of the drivers seat just above the floor. while i haven't used it yet the pass side tank that is on the truck has always been routed through this valve. i just haven't filled the driver side fuel tank with fuel and ran it yet. the previous owner had a cheep plastic fuel tank on the drivers side that was split at a seam and was only held in with plumbers strap. that got ripped out the first day i got the truck. that tank had a filler neck that exited in the wheel well area. if i were to hit a mud puddle it would have got covered in mud so i ditched that.