I'm looking at building my 50 mercury as my daily and with that fuel mileage is a big deal. What kind of fuel mileage do guys get with mercury both swapped with small block chevy etc? Please list motor and fuel mileage you usually get. I'm thinking about a 350 chevy with a 700r4.
My mild 8BA with dual 94’s get 15-18 mpg on the highway on my 37 coupe original 3 speed with highway gearing. I can’t see a SB getting much better than that.
Insufficient information. The 350" has been built for more than fifty years, with different compression ratios, intake systems, exhaust systems, ignition systems, with and without digital controls. Then, you haven't chosen a rear gear. Tire width and construction is a real factor. There's a potential of 5 MPG spread between the best and worst combinations. A WAG would say between 17 and 22 at cruise. In town, 16-17. jack vines
Your build, your money, your decision, but 2.90 is pretty tall. In overdrive lockup, it's down to 2.03. With typical HAMB 27" tires, the 350" will be cruising down around 1600 RPM. That only works with the later EFI, electronic control of ignition and a knock sensor. Trying to pull that gear in a Merc with a carb and vacuum distributor maybe not so much. jack vines
chevy made them work with gearing like that with a Quadrajet carb....but it would be more fun to drive with gears in the mid 3s.
I think it depends on the type of driving you are doing. Around town, highway? Wouldn’t want to drag some 2.90:1 gear around town for sure. I’d also consider a 2004R trans. Much lighter and lighter rotating weight. That and a 3.50:1 gear have some fun!
I've got a 3:00 in my car behind an AOD. It won't stay in overdrive at speeds less than 60-65, so when cooler weather gets here I'm putting in a set of 3:55's. I'd say 15-17 mph is a good guess.
This is a traditional hot rod forum. I was there in the fifties, sixties, and forward. I don't remember even thinking about gas mileage until I bought a new '73 Riviera with a 455 6 weeks before the first Arab oil embargo.
I had an O/T '92 Roadmaster, and I expect the engine/trans/rear combo were the same as in the '91 since it did not have the trailer towing option. I consistently got 28 MPG on the highway with it at 60 MPH. I have a light foot when in a daily driver.
Well as far as traditional goes it was done by young kids without a ton of cash. I myself don't have a ton of cash and with gas over 4 bucks a gallon if I want to be able to enjoy this car I need to get as good as possible.
around 20mpg would be my guess. A friend has a 50 merc. 350/th350 w 2.73 gears and gets 18mpg at 70mph.
Is it roller hydraulic cam? Personally you are on the right path. There is no reason why your combo would be worse than the donor vehicle. Consider it a body swap. The Mercury should be almost 1000lbs lighter than the Buick While you are at it, cannibalize the front brakes and M/C to match the rear brakes . After all this, if you are still motivated by economy, install 305 heads (better still L98 heads) a short duration cam, and recurve the HEI. 25 mpg is an easy goal with a very user friendly cruiser.
A 91 Mopar was EFI, is the 91 GM going to be? Makes a huge difference concerning drivability with the rear gear choice and OD. I would expect 20- 24 highway (65-70 mph), and 13-17 city (25-30 mph), but how you drive it will probably have more effect then what it is. Neither my wife nor I drive for the best mpg, but in the same vehicle, I usually get 2-3 mpg better then she does.
My friends '50 has a 283 with a stock 350 cam profile, 3x2 (2 jets), Saginaw 3spd with o/d and a stock Merc rear (3.55 ???). He says he gets around 19-20 mixed (mostly freeway), he was driving it daily. @Some Guy
I'm thinking the same, ***uming the wheel diameter remains roughly the same (that affects total gear ratio), and the aerodynamics aren't extremely different (the latter being most relevant at high speed).
Daily drove my 1950 merc for 9 years. Built it for my 20 miles to work and my 20 miles return. Stock rebuilt 283 with triple deuce carbs. Summit SUM-1102 camshaft. Original 3spd on the tree overdrive transmission, (after about 7 years I swapped to a Saginaw 3spd overdrive). Original dana 44 rear end, rebuilt and re-geared to 3:55. Stock suspension (lowered). Stock steering (changed to power after about 8 years). Jamco front disk brakes. Radial WWW tires. Hugh MPG improvement over bias. I average about 16-17 MPG or just over 2 gallons on my mixed freeway, side street commute. Took the car off the road a couple of years ago to do alot repairs and new interior.
Just my $0.02. Why do you want to daily the '50 Merc, especially in SE Iowa, where the weather is suspect at best? A few years ago, I moved across the country for a new job. I showed up at the new location with my '85 F350 Dually and 24' enclosed trailer. That truck is great at pulling the trailer full of furniture, but not so good for commuting the 60 miles round trip each day I had to go from the apartment to work (14 mpg - highway, unloaded, diesel). I bought a cheap little Ford Focus. 5 spd manual - 42 to 45 mpg. The loan payment + gas for the Focus was less than the fuel alone for the F350, let alone the extra maintenance expense that comes with keeping a 35 year old diesel pickup (and one that was built during a time period where quality was not exactly "Job 1") going on a daily basis. The same thought process applies to your situation. Why not purchase a cheap little reliable car with a super low cost of ownership for commuting and put the extra money saved into the Merc? Than you can build it and drive it how you want and not worry about silly things like fuel mileage which should have no bearing on a custom car.
Because for me that is not the point of the car. I wont drive it in the salt but I will in the rain and sunshine. No point in putting in all the work to just park it and stare at it and shine it. I HATE little gas cars and already have a van that gets 26mpg now. I want to build my merc to drive it daily and enjoy it. I have no interest in taking it to car shows etc, just want to drive it. The cheaper it is to drive the more I can drive it. I plan on taking this car down the entirety of route 66 with my 3 kids and my wife. I'd like to do that at better than 12 MPG. And like stated before I want to daily it, I don't want a mint show car
I fully understand Tony's point of view. I drive my 48 Plymouth an average of 8,000 miles a year, but covid dropped it to about 6,000 miles the last couple years (hard to drive when no place is open to use a rest room or buy food). I'm retired now, but drove the coupe for about 7 years before retirement, but I was self employed and worked out of my home garage. Sometimes the change in weather between the morning drive to work and the drive home after work can be dramatically, just be sure your chosen ride can handle a really rough drive home if the weather turns bad. I promise if the weather turns to ****, the gas mileage will not be your biggest concern (unless your nearly out of gas), it will be being able to see through the windshield. Functioning defrost (and wipers) are more important then heat, AC, or fuel mileage. Been there! In my book, 20 mpg is a reasonable number for a daily driver. Life is short, if you got to drive, might as well enjoy the drive. Hard to enjoy driving a cracker box, even if it gets 2x the gas mileage. Driving an old car home can vastly improve a bad day at work. Gene
I just did a build with a SBC/700R4/3.08/27.7" tire. Engine has dual quads on Edelbrock C26 intake, headers, true duals, 8:1 compression. It could use more gear in the rear. I mean, it runs and drives fine, but it lugs on the highway because to run at a 70 or so, it's below the power band. When it starts to get into the power band, I'm running the risk of a bad speeding ticket. I agree that a 3.50-3.73 would be optimal, depending on tire size.
I checked curb weight on the 50 Merc (3640 lbs.) and the 91 Buick Roadmaster (4096 lbs.). Difference is 445 lbs. Theoretically, your Merc should do just fine with the drivetrain out of the Buick. With that drivetrain, the Buick got 15 mpg around town and 23 mpg on the road. I'd say go for it.
I once borrowed a 2015 Ford F-350 from a friend to pick up an antique stove. I got 17mpg out of it. He asked me if I pushed it most of the way because he always got 12mpg! Driving technique is always a big factor in the quest for better fuel economy.
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