Nobody warned me about the MPGs on these square bodies!

[WranglerTJForum]

Yes but I think staying holley will cost a bunch more and doubtful as good of end results. Could only insert 5 pics but you can get just an ep 381 genuine GM for less than 50.00, your hydramat costs more than a gas tank.

FWIW, I picked up two 12-308 Holley fuel pumps for 20% off at Autozone online of all places. They were having a sale and it was too good to pass up. The 12-308 pumps come with the Hydramat as well. All in all the pumps were $380 each.

More expensive than the GM pumps and EFI tanks or maybe right about even.

I suppose I could return everything and get the parts you're suggesting, but people seem to really like the Hydramat.

Anyways, I'm into it for $760 total.

 

[Old Guy Bill]

The 400 sbc in my '78 K20 has a new Holley 600.
With 33" tires and a 400TH and 4:11 gears I swear I can see the fuel gauge move when I floor it!
I keep both 20 gal tanks full!

 

[WranglerTJForum]

The 400 sbc in my '78 K20 has a new Holley 600.
With 33" tires and a 400TH and 4:11 gears I swear I can see the fuel gauge move when I floor it!
I keep both 20 gal tanks full!

Unfortunately with my short bed I’m stuck with the 16 gallon tanks! The 20s would be much nicer.

 

[WebMonkey]

Not sure how to say this but I’m not sure how an old K20 could get that kind of mpg unless going downhill with a tailwind.

i gotcha.
it's just guesstimate math at the pump.
3.73 rear on skinny/stock height tires.
reman/furb quadrajet, easy on the shifting.

road to town is 55 mph, 20 miles each way.
i don't do 'town' driving so that helps.
(1 four way stop and 1 traffic light to get where i gotta go)

go to the scrap yard or feed store and back

'monkey

 

[chief_shotts]

For reference:
383 stroker. Crew cab. 35in tires. 4.10. Turbo400. Np 205. Holley sniper. 8-9 mpg.

Sounds about right to me.. especially if you drive with conviction.

 

[Soundmound]

I have absolutely no clue what my mpg is yet... I'm hoping to figure it out on the way to Fall Revival though. My '84 is a 305, dual 16 gal tanks with fully functional tank switching, ESC, computer controlled carb, cruise control, California emissions, 700R4, 3.08 gears, deleted cat, 3" exhaust from the collector back and rolling on 20's. I am hoping for double digits but couldn't care less if I don't get them. The smiles to miles is worth every red cent!

 

[Grit dog]

I have absolutely no clue what my mpg is yet... I'm hoping to figure it out on the way to Fall Revival though. My '84 is dual 16 gal tanks with fully functional tank switching, ESC, computer controlled carb, cruise control, California emissions, 700R4, 3.08 gears and rolling on 20's. I am hoping for double digits but couldn't care less if I don't get them. The smiles to miles is worth every red cent!

Whole different ballgame than the trucks that have been discussed. Driving 60-65 I bet your truck gets 15 easily.

 

[Moodyalaskan]

Just averaged out the MPG on my 85 Chevy 3/4 ton, 305, 700R4 stock size tires. Not sure of the gear ratio. Vancouver, WA to Chugiak, AK. 16.5MPG, 55-65mph up to Whitehorse and then 45-55 to Chugiak, do to transmission leak. 2532 miles

153.5 gallons gas
8 qts dextron III
3/4 qt 10W30

 

[DoubleDingo]

I have absolutely no clue what my mpg is yet... I'm hoping to figure it out on the way to Fall Revival though. My '84 is a 305, dual 16 gal tanks with fully functional tank switching, ESC, computer controlled carb, cruise control, California emissions, 700R4, 3.08 gears, deleted cat, 3" exhaust from the collector back and rolling on 20's. I am hoping for double digits but couldn't care less if I don't get them. The smiles to miles is worth every red cent!

It'll be 8-ish

 

[Ricko1966]

I have absolutely no clue what my mpg is yet... I'm hoping to figure it out on the way to Fall Revival though. My '84 is a 305, dual 16 gal tanks with fully functional tank switching, ESC, computer controlled carb, cruise control, California emissions, 700R4, 3.08 gears, deleted cat, 3" exhaust from the collector back and rolling on 20's. I am hoping for double digits but couldn't care less if I don't get them. The smiles to miles is worth every red cent!

So we have people guessing any where from 8 to 15. You will have to post the final numbers.

 

[Broken85]

Yes but I think staying holley will cost a bunch more and doubtful as good of end results. Could only insert 5 pics but you can get just an ep 381 genuine GM for less than 50.00, your hydramat costs more than a gas tank.

I have a sniper with the Holley 12-308. I installed new tanks as well. Those baffled tanks are harder to find and not cheap. I went with the 12-308 because they were supposed to work with the OEM non baffled tanks and the “hyrdrasock “ was supposed to mitigate fuel supply loss. With new tanks and new 12-308’s, I can only draw 12 gallons out of my 16 gallon tanks before it leaves me stranded.

Not happy about losing 25% of my fuel capacity, but atleast I have two tanks. Maybe it is a tank problem, maybe the pickups are not low enough, I don’t know but they only go in one way. Maybe one day I will be ready for the aggravation of doing the whole job over with new tanks, but not today.

 

[Ricko1966]

I have a sniper with the Holley 12-308. I installed new tanks as well. Those baffled tanks are harder to find and not cheap. I went with the 12-308 because they were supposed to work with the OEM non baffled tanks and the “hyrdrasock “ was supposed to mitigate fuel supply loss. With new tanks and new 12-308’s, I can only draw 12 gallons out of my 16 gallon tanks before it leaves me stranded.

Not happy about losing 25% of my fuel capacity, but atleast I have two tanks. Maybe it is a tank problem, maybe the pickups are not low enough, I don’t know but they only go in one way. Maybe one day I will be ready for the aggravation of doing the whole job over with new tanks, but not today.

You know 1987 tanks ( baffled tanks) are only about 100.00 each now. IDK what the were priced when you were shopping but I consider 100.00 a piece cheap.

 

[chief_shotts]

You 1987 tanks ( baffled tanks) are only about 100.00 each now. IDK what the were priced when you were shopping butbI considerv100.00 a piece cheap.

Was just about to say the same thing. And ya 100 dollars for a new gas tank is very reasonable deal.

 

[chief_shotts]

I have a sniper with the Holley 12-308. I installed new tanks as well. Those baffled tanks are harder to find and not cheap. I went with the 12-308 because they were supposed to work with the OEM non baffled tanks and the “hyrdrasock “ was supposed to mitigate fuel supply loss. With new tanks and new 12-308’s, I can only draw 12 gallons out of my 16 gallon tanks before it leaves me stranded.

Not happy about losing 25% of my fuel capacity, but atleast I have two tanks. Maybe it is a tank problem, maybe the pickups are not low enough, I don’t know but they only go in one way. Maybe one day I will be ready for the aggravation of doing the whole job over with new tanks, but not today.

The baffled tank is 100% the solution. When I installed my Holley sniper I plumbed my 87 baffled tank with new lines and installed an inline pump on the inside of the frame rail. I did all the work with supplies found in the sniper master kit... 5ish years later everything still works and I've never run out of fuel. Ive got the tank fairly low many times.

 

[Broken85]

You 1987 tanks ( baffled tanks) are only about 100.00 each now. IDK what the were priced when you were shopping butbI considerv100.00 a piece cheap.

That’s good to know ! They were twice that when I was lookin (but that was in the middle of the Biden inflation apocalypse) compared to $90 for a nonbaffled tanks and Holly said it didn’t need to be baffled so why spend the money. I’m not even sure if the baffle would fix the problem honestly. Still could be a pickup issue.