Which gets better mileage? 305, or 350?

[Skunksmash]

At first i guess it would seem the 350 should get slightly less, but that is not always the case with engines. I have seen smaller factory motors get the same or less than larger ones. I used to have an all stock 95 GT mustang 5.0 and the v6 my Girlfriend drove got the same mileage my car did. Around 22 mpg. In these times of extreme gas prices, i might like to build (or buy) a 305 to go in my truck until the whole gas war thing calms down. What do you think the best V8 engine would be for mileage? The first one that comes to mind for me is a 2 barrel carbed 305. I used to have one in an 82 silverado longbed, and that thing got around 20 MPG. Not to bad for a full size truck. I got a brand new F-150 work truck and that thing gets a pathetic 17 MPG. (course it is a ext cab 4X4) My old 82 with the 305 wasnt a hot rod, or fast by any standard, but it would pull a boat or a trailer with an average car on it just fine. And i can always switch back to a 350 if i want to. What is your opinion? Which V8 do you think could be made to achieve the best mileage?

[Lt.Del]

I got a brand new F-150 work truck and that thing gets a pathetic 17 MPG. (course it is a ext cab 4X4)

That's not pathetic.  I wish my 383 stroker engine got that in my 79.  I'd jump up and down then do a Tiger Woods Pump with my arm.

Many here would say you can create up setup with a 350 and a higher gear rear (if you do a lot of highway driving) and tune the carb so that it could get close to 20.  Fuel injected would be better. However, you can do the same with a 305, which may get a little better, if it has the umph to do what you want. However, if on a 305, you have to keep the gas pedal down further, it will use more gas.

 

[cracker0169]

I'd jump up and down then do a Tiger Woods Pump with my arm.

Then you would be out of work with a bum knee!

My 305 with a 2.76 rear gets me about 15 mpg but it is mated to a th400 and has had "some" work done to it. Its fed through a 600 Edelbrock, 9.5:1 compression, long tubes, big crane cam.

[Skunksmash]

Hmm, so 3:73's would be better for city mileage? I would like to pull out every trick in the book to get better mileage. I hear aftermarket headers can do it. As well as a hotter ignition system. Any other options? I really dont care about having tons of power. I mean i would like to be able to pull a fiberglass bass boat, but thats about it. If i have to sacrifice power as long as i can still do that, i dont care.

[Lt.Del]

a 3.73 is a low gear but may be what you need for city driving---so you won't have to keep gas pedal down all the time with a taller gear.

I have 3.08 in my 79 w/ the stroker engine.  I wish it was a little lower gear, say around a 3.50 or so. I do little highway driving with it.  However it is nice w/ the 3.08, the rpms stay kinda low. 

[Fordeatinz71]

well, basically, what SgtDel said is the key.  if you can keep the 305 from struggling (not an easy task in such a big pickup) then it will do alright, but in my experience a 350 will get better mileage 80% of the time in these heavy trucks...


BTW, 90% of statistics are correct 50% of the time...and 100% of the time you can get statistics to say what you want 'em to...lol

[cracker0169]

In my opinion, a 5 speed is the way to go. I would like to swap in a t5 from a camaro so that i have a tight ratio to run through the gears as well as a good OD ratio (.7:1 I believe). I could then jump to a 3.73 gear set and have the best of both worlds. I could pull whatever and then grab a hold of OD on the highway and keep the revs down. Not to mention, sticks add to the cool factor...

[Skunksmash]

Standards are really not my cup of tea, unless in a sports car. I like my truck for cruising, hauling stuff, and showing off something pretty. I would not want to have to be shifting gears while doing all that lol.

[Captkaos]

What is the current setup of the truck now?  Realisitcally you can build either motor for mileage, you just need to put it together as a package.  What one person gets in mileage won't be the same as someone else.  Grandpaw who never drives over 55mph on the highway is going to get better mileage than an 18 year old running 75-80mph in the same truck.
3.73 gears are going to be to much, 3.42's is a better choice and Overdrive trans would be best.
Check the what mileage are you getting post...

[SUX2BU99]

Going with a 700R4 overdrive trans is probably your best bet to keeping RPM's low on the highway for good mileage. Around town it's hard to say 305 vs. 350. Just like V6's in full size trucks, they have to work a lot harder to pull around the same weight. 305 wouldn't be so bad. You could build a totally economy 305 with a really mild cam, QJ carb for the tiny primaries, etc. and put tall gears in it like under 3.00.  Keeping it in excellent tune though is key and so is a really light foot.

[TexasRed]

I'd get the S/R Torquer heads for the 305 too.

[Skunksmash]

My current setup it just a stock 350 with an automatic tranny. I assume it is a 4 speed (thank God) because it has that little circle around the D for "drive" on the gear selector. As we all know that circle is supposed to be an "O" for overdrive. 87 long bed TBI is the type of truck. Silverado, but I guess that part does not matter lol.

But I thought a 305 was plenty powerful enough and would not be having to work to hard to pull around a typical half ton truck. I may be mistaken here, but in comparisson to a lot of the cars out there, they really don't weight that much. What is the typical weight of a stock truck? 3000lbs? Maybe 3500?

[werewolfx13]

3000 lbs? 

4500 for your '87 longbed is closer to being right..
My '83 shortbed, completely empty except for me (225 lbs) and a full tank of gas, weighed in at over 4000 lbs...almost 4200 actually..I probably have the scale slip stuffed in the sidepocket...

[Captkaos]

3900 for a SWB and 4200 for a LWB on the non-equipped side.

My 89 (same as the 87) 305 has plenty of power for pulling my 15' Seadoo Speedster, and it gets respectable mileage also.

[Skunksmash]

In times like this, where we have extreme gas prices, i think we need a sticky at the top of one of the forums that goes over all the things you can do to improve your mileage. Even if it just little things. By the time a person added up all the little tricks in the book, i bet they could see a 5 mpg increase. Would be awesome to have all the tricks in one place.