Hot Rods 283 sweet spot

Gregg : I know what it is....them funky spiked mirrors are causing wind resistance of the third order...
Just sayin....
Stan

 

Your probably right Stan. Don't tell my brother but I saw a pair of those mirror's that where roached on E-Bay. 300.00$ .So the the big question is did you go buy Pegs truck ?
Gregg

 

Still dodging that bullet...

 

Chicken

 

Do you have different blends of fuel for winter and summer,we do up in Ohio and the winter blend will get less mileage.

 

My '40 in the avatar gets about 15-17 @ 60-70 mph with a mild 283, 3:78 rear, stock 3-on-the-tree. 255-70's on the rear. No tach, but guessing 2800-3200 at speed is probably close.

 

WOW that's great. I'm not holding out for that but it would be nice.
Gregg

 

Jeff if we have different blends I don't know about it.

 

My wife read the thread. She states cut out the floorboards and do the Freddy Flintstone. LOL I drive a stock 66 GMC and it weighs about 4300 and pushes a lot of wind. 250 six with electronic HEI SM420 granny 4 speed. Its a half ton with 410 gears. And I run a 180 degree thermostat. I installed tall 16 inch tires on the rear. and It will run 65 pulling my stock trailer however at that speed it uses a lot of fuel. Normal driving it don't use very much gas. Back in the day most 283,s even with a 4 bbl carb from the factory ran a single exhaust. Put dual exhaust on a 2 bbl 283 and fuel economy suffered. Because you improved the efficeny of the air flow through the engine. more air flowing = more fuel being burned. and blocking the heat from the intake manifold crossover greatly reduces vaporization thus increasing fuel consumption. Years back Smokey Unick built a engine that got phenominal fuel economy. And he ran that engine at extremely high temps(it used a lot of cremacs). and it had a thing he called a homonizer that thoroughly mixed the fuel. Back in the day we had much better gas it made more power. Todays gas don't make as much power.

 

Well had a good news bad news kinda day. The good apparently the timing change and 500 carb helped my around town milage. went from 7.5 mpg to 9.6. The bad I took it on a 50mi. cruise on the highway at 65 mph and only got 9.8 mpg. I was stunned that the mileage was virtually the same for both city and highway mileage. I will install the 700 r-4 in the next week or two and see what that doe's.
Gregg

 

If the motor is fresh you might want to put a couple thousand miles on it before checking the gas mileage since its tight.

 

Maybe your right Jeff. I hope so but it's still getting an OD trans
Gregg

 

I read this whole thread and feel like you left me hanging!
Did you get the ****** in and have any better results? Did you try something else and achieve good results?
Take care- L7

 

dammit gregg...get back on here and finish the story

 

Yes I did put in the OD trans. Believe it or not it got worse. At 65 mph was only getting 10" of vacuum and 8 mpg at around 1400 rpm. This was in OD with converter locked. I wire converter to a toggle switch when turned off got 12/13" of vacuum and 1700 rpm. I found that 2000 rpm seems to be the (sweet spot) at that rpm getting 12/13 mpg and pulling 15/16" of vacuum. So 3 carb's 2 cam's 2 distributors and an OD trans it appears that 12/13 mpg is as god as it's gonna get. It get's 10 mpg around town. I kinda got disgusted and stopped posting about it. Good new's is the truck run's and drives great. It has become my daily driver so it is what it is as far as mileage . For me at least the 283 works best in a light weight roadster. If I build another truck it will have a 350. I have one in my 51 Chevy coupe and it get's 16 mpg all day. So I love the 283 but not apparently a good choice for economy in a larger heavier car or truck. I am going to pull the 350 from one of my roadster's and put it in the truck and put an 097 duntov solid lifter cam in the 283 and put it in the roadster . I'll throw some 4'11 gears in it and buzz the **** out of it. With the exception of the cam all parts changed out during this whole thing I already had .So while I spent a lot of time I didn't spend a lot of money.I learned a few thing's along the way. So it was worth it if this **** was easy everyone would do it.Thats the end of this saga.
Gregg

 

097 cam is the way to go. There's one in the 283 +0.060" in my '40 coupe. I get 15 - 17 mpg with Edelbrock 650, 225/75 radial, 3 speed manual and 3.78 gear. Even if it doesn't help mileage, it sounds (and runs) great.

HAMB parking at the Turkey Run this year?

vic

 

Yea Vic that is a damn good cam. I have one in my 29 roadster and love it. I think I'm going to love it even more as soon as I finish installing my 4 speed stick. Yes there will be HAMB parking again this year.
Gregg

 

Interesting thread. Probably not the results you wanted, but at least you reached a point where you know what you're dealing with. The main thing is it runs good and you're driving it.
I had 283's in two cars, a '39 Ford coupe and a '39 sedan. And I still have a 283 in my garage now that I hope to rebuild and use in something someday.
My '39 coupe had an auto with a boneyard '68 Chevy II rear, fairly tall gears (3:08's?) and 15" tires on stock steelies. Highway mpg was mostly mid-to-upper teens. Bone stock 283 2-barrel with factory intake and Rochester carb, only mod was dual exhaust and some chrome.
When I started pulling a camping trailer, the tires would rub a bit when the car was loaded down. So I put 14" alloy rims on it all the way around. Sat lower but level, no rake - less style but functional. With the lower profile radials on the rear, engine rpm's went up - how much I dunno, never had a tach in the car. But I found the non-towing highway mileage actually got better. Pulling a trailer, not so much. So yes, there is something to that "sweet spot" jazz. The coupe always seemed to run best about 10 mph over the speed limit!!
The '39 sedan ran a pieced-together 283 4-bbl., turbo, 8" Maverick rear with 2-something gears, and 235-75-15 rear tires. Somewhat gutless and I think the best I ever got with that was maybe 15-16 mpg. But I put quite a few miles on it, the car rolled down the road like a breeze and sounded great doing it.
As you have found out, 283's may not be the optimum mileage engine in a heavier vehicle but I always liked it when I popped the hood and someone would ask, "350?" I'd say, "Nope. 283".
And they'd always grin.

 

Gregg- Thanks for the follow up! Sorry you didn't really get the results you were hoping for but, sounds like you have it all under control. Have fun!