Abso-freekin-lutely! Back when my job required an average of 450 miles per day I wouldn't have been able to drive my hot rod everyday and turn a buck if I hadn't made it as efficient as possible. Driving a late model is and never was an option in my book. Never owned a car I didn't build on some level, never will. See above and know that my avatar happily runs high twelves, runs out of aerodynamics at about 140 and still turns back about 20 mpg at 85 mph. Your an idiot if your not shooting for the same in a car you drive everyday. it has nothing to with being "green" or an enviromentalist, it's all about making something the very best it can be. I won't settle for less. Very true, the tune IS the name of the game. In my mind the tune includes gearing, trans, overdrive and ch***is prep as well engine. Make that thing a whole unit that works together optimally. Bingo again!
One of the best reasons ever! One of my former daily runs was Phoenix to Yuma on hiway 8, and basically from Gila Bend to Tacna is about 100 miles of nothing.
i ask for the fact the rest of the hot rods i am running with have overdrives and bigger tanks. some of them will be towed also. so i just curious about the setup, when one gets ready to drop alot of cash on a new setup i would like to have an idea where i would end up with my purchase. thanks to all gave their input on what to do with the direction i am heading into. it seems to me the 350/290 gm crate with a turbo 350 will be good enough for my c-dan. the 2.79 gear will more likely stay was thinking maybe going to a 3.00 gear but dont know yet. the 283 is getting tried and i plan on saving it for a future project down the road. i put 12,000 miles on this hot rod in the last 4 years driving everywhere. no complains just want to make this one a more of a daily driver to work, then long hauls like out west and anywhere i want to go. i know lot of folks have gone the overdrive route, i was just debating if i should follow their path. as far as mileage if i get 20,25, or even 15 mpg i not going to ***** or worry i just want to hang with the pack i am running with and not stopping for fuel every lil bit. sometimes this board is a really good source of information when needed and other times there is just alot of jack***es show what they are made of. sorry for the WTF, i knew when i would ask about mpg's hot rod people would say WTF. thanks again to all.
Maybe I'm over-simplistic, but with a 350/350 and 'typical' hot rod tire cir***ference, it seems like changing from a 2.79 to a 3.20-ish ratio would make it MUCH more drivable without an impact to mileage... call it done.
On my 55 ford f100....I was getting a little over 14 mpg with a 3.25 rear end...I then only changed the rear end to a 3.00 and started getting 18 mpg...I was surprised at the huge difference in mileage with such a small change in rear gear ratio. On the negative side, I also noticed a " less lively take off".
I'd say that most of the nay-sayer's have never contemplated an actual road trip. By that, I mean having to fuel up more than once a day....Sometimes, for some people, 5MPG might make the difference between even being able to afford to drive your hotrod somewhere. 4:11's might be awesome for you guys, but if the only way you can afford to drive halfway across the country is to rent a late model, what good is your hotrod. These cars are meant to be driven, My 55 doesn't do to well on fuel mileage, I like the performance just the way it is though, so my next build, with the idea in mind of taking my son to the salt flats when he's 11 or 12, is a mercruiser powered T roadster. We probably couldn't afford to make the trip in my 55, so, should I deprive myself and my son of that experience, just because I want to be a "cool hotrodder" ??? Now, you might be saying to yourself, well, that's dumb...take the money you're going to spend on the T and buy gas...Good point, but then I'd still have ONE car....soon, I'll have the best of both world's, a 55 2 door hardtop AND a roadster... As for the OP, I think maybe you gear choice will be putting that 350 below it's optimal cruise RPM, therefore, hurting your mileage.
Vic, Sometimes the numbers don't add up the way we think they should. With a single 4 on my 355 @ 3000 rpm I consistently get 20-22 on the highway. My problem is that 3000-3200 is the sweet spot on that engine so in order to get claimed mileage I have to be geared to be able to cruise @ that RPM. In the pusher with the 3.08 gear the RPM is about 80 mph. A little higher than the law wants. The idea is to maximize your efficiency. A well tunned performance engine is an efficient engine. The problem is that in order to maximize your efficiency you have t choose a gear suited to your driving habits. 80 MPH is a little fast and I would have been better off with a 3.73 gear in that 4000 lb brick. That would have put me @ 3000 @ 65 mph. Does that make sense, your gear must match your entire combo for a given RPM range. Where I see a lot if the fellas screw up is they throw an OD ****** in or an exceptionally tall gear in and just think that it will improve their fuel mileage when in most cases it puts them at too low an RPM for the engine in question and they do two things, they either keep the same mileage or loose mileage and they lug their engine around which eventually causes damage to the engine. It is hard for people to grasp. You have to think about what the capabilities of your engine is prior to chooseing a final drive.
I agree. My 40 has a 327, turbo 350 trans, 29 inch tire, holley spread bore carb, and a Crane RV grind cam (I know some of you guys hate the term RV grind, but that's what they called them) I used to run a 3:70 gear and on a long road trip I got an honest 20-21 MPG, and that was at 75 MPH average. I later changed the rear to a 3:25 for another road trip and the mileage did not improve. Of course the RPM dropped 500 or so making the engine a little happier. But I miss the 3:70's so I might put them back in and let the old small block wind!
Basically where I was going with this is drivetrain is exactly the same except for the new crate 350 / 290 and you are improving that from your 283 / 200 why would you be concerned about your gas mileage going in the toliet? Unless your foot is in the 4 bbl all the time it is still a 2 bbl(basically). Your mileage should only vary about couple mpg either way. Yes I understand make it as efficent as possible. If this was the concern you should have bought a 5.3 LS w/fuel injection and a 4L60E. Bam! Efficiency mystery solved. Budget yes I get that also and you didn't build a 500 horse aluminum headed roller 355 or change the ring gear to a 411 and expect it to get 20 mpg. You have are running a great combo. I would bet you will get a little better mileage out of this combo than the 283 just because the engine is more efficient, better heads, intake, etc, but will you get 25mpg? probably not, but maybe 23mpg and if you want to get 25mpg change the ******. Want 26 mpg change the gear also. You can make it just about as efficient as you want it to be, but at what point do you draw the line? I guarantee when WE ALL got into hotrodding none of us said "man I gotta make my Rod as efficient on fuel as I can!" I bet it was more like "man this motor is gonna run great and the car looks *****'n. I was really hoping it would get 20mpg and it only gets 18mpg. Oh well I can deal with that!" And to all you "spots in AZ people where there are no gas station for 100 miles" folks if you only have a 5 gal tank and cannot read the signs on the side of I-40 that tell you how far it is to the next fuel stop you probably shouldn't be making the trip anyway. I have driven that stretch of road 3 times, so yes I know the areas you are talking about. ANY THOUGHTS? Yes! Lets use some common sense.
I often run several hundred miles to shows so I try to achieve some mileage as well. My 68 biscayne, 283, 305 80's heads, 266 cran energizer cam, edel 600 cfm, hei 3 speed manual , 26" tires, 3:36 cruised 65mph easy and got 24mpg. My 63 bel air, worn out 283 2bbl(HEI), 3 speed, 3:55's 26tire gets 16-17hwy. My 55 has a mainly stock 400 quad, performer intake, 200R, 3:55's gets 16-17 as well. It wasn't as good as first then I put in brand new hei and she ran better and got better mpgs. I'm convinced if it was a 350 I'd be getting 20 with it. 400's were never known for mpg but couldn't p*** it up for the price. I'm on the fence about a smaller cube motor for my 58 wagon. If its working too hard then mileage wil suffer. Maybe a mild 307 would be the call. Do the easier thing and test and tune your current and then try the 283. I like trying other combos besides 350/350 but I'm usually starting from scratch anyway not pulling a good running motor.
It Sure does make sense, its all a compromise. An engine could be built with a 1700 rpm sweet spot or a 7000 rpm sweet spot. Gear it accordingly and it will work the best at its intended purpose. Back when 55 was the national speed limit driving anything built in that period over 55 really hurt your milage. Since the limit was raised, most things built after that get ****py mileage @ 55 better if its higher soeed . My daily gets better mileage in 3 rd gear for anything under 57 mph. Yea lots of folks have trouble grasping the rpm sweet spot. Remember my "max torque @ cfm thread " ? Building and ending with Cruise rpm below the sweet spot rpm is going to cost plenty. Lugging an engine is hard on parts and fuel economy goes right out the window.
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