Anyone have any suggestions for improving gas mileage on an old 302? I'm thinking all the run of the mill stuff like upgrade the air filter, better flow through the exhaust, tune up with top notch plugs and wires. Then, of course, check all the normal stuff like tire pressure and whatever. Run a carb cleaner and all that jazz.

What if I eliminate as much rolling resistance in the rear differential as I can. I've heard this can help but I am not sure to what degree.

Should I replace the stock carb for something more modern?

Should I use higher grade fuel on an old truck?

I know I ask a lot of questions, I just want to be sure I'm treating this beautiful machine right. It's my first big engine.

 

You can replace your mechanical fan for an electric one and that will help. And you can change your gear ratio in the rearend, If you change the ratio you wont be able to pull as much but in return your milage will increase a ton. If the engine dosent have to run as many RPMs you save fuel.

 

That could work because this is definitely not going to be a truck for towing or helping friends move. haha. Thanks for the tip.

 

No problem

 

You can swap in an EFI system for your 302 (rather it be aftermarket or the junkyard [but if you went the junkyard route you might need the engine that the computer is connected to])

 

Just as an attempt to straighten out this misconception:

(Taken from one of my posts on another forum)

 

I have always wondered about that. Because I've run 89 in a car which specifically instructed me to use 93 and I had absolutely no issues.

 

Cars that prescribe higher octane fuel typically have higher compression engines. As long as it's not pinging, it's fine for the most part.

 

It's been my experience that cars that call for higher octane fuel eventually start running badly if lower octane fuel is used.

 

Well... it "recommended" premium.

I'm thinking this EFI thing might be the way to go. Is there an after market performance EFI that might improve mileage or should I just go with one from another truck?

 

Holley make an EFI system that you can buy "off the shelf". But, it is cheaper to buy the EFI system with the engine that is supposed to stay with it from the junkyard.

 

I want to make sure I understand you here. Are you saying it's cheaper to buy an entire engine with the EFI on it than it is to buy a Holley system?

 

HA! Nevermind. I found the answer to that one on my own. $2,000+?! I don't wanna save gas that bad.

 

it's hard to spend money to save gas and make it pay off.

it's better to do it because you want to, not as an investment, so to say.

the best thing you can do is a good tune up and make sure all the vacuum lines and emission controls are in good working order.

i know you said it's your first "big engine", but a 302 is pretty small and makes a pretty good compromise between towing power and daily driving.

IF you want EFI, then find a donor vehicle and steal everything from that, but if you just want it as good as you can get it, a good tune up and an upgrade to electronic ignition if you don't already have it (not sure what year you have), is probably the best thing to do.

 

Well, I know a 302 is a small block, but it's the first V8 I've ever owned. I'm not really sure I want to invest in an EFI swap, but I would like to make sure I get the best mileage out of the carb if I decide to stick with it. I have considered a distributor upgrade for sure.