Technical Chevrolet 283 build for fuel economy

Hi!

I'm building a 283 Chevy for fuel economy and low end torque for my 1957 Chevy truck.
Bored .030
The block is decked and slightly milled 896 heads.
Compression is going to be 9.5:1

I need some help deciding the camshaft and intake setup.

Should I go 2barrel with the original Rochester 2GC carb and the stock 2barrel camshaft?
Intake Duration at .050 Inch Lift: 172
Intake Valve Lift: 0.333 IN
Exhaust Duration at .050 inch Lift: 172
Exhaust Valve Lift: 0.333 IN


Or should I go 4barrel with the stock 4barrel camshaft?
Intake Duration at .050 Inch Lift: 194
Intake Valve Lift: 0.390
Exhaust Duration at .050 inch Lift: 202
Exhaust Valve Lift: 0.409

And remember this is not a performance build my priority is a nice daily driver engine with good fuel economy.

Best regards
David

 

you have a 3.9 or 4.11 rear so go 4 bbl cam as cruise rpm closer to its sweet spot

 

I am going to run a 3.36 gearing and a TH350 with lock up.

 

I'm voting small 4 barrel and cam. The 283 I had in my 20's was flat tops, small Sig Erson cam, headers and a Q jet. Stay out of the secondaries and it got 20mpg with a 3.55 rear in a 3500 lb car.

 

When the cam lobes in my O/T Chevy truck went flat I asked my friendly speed shop salesman,
for a Crane RV Cam.
The result was many happy miles with a very light right foot.

 

Advance the stock cam to 6*. Remember it may be ground with some advance in it. Also your truck is a brick with very poor aero. Skinny tires with 45 psi in them. 15-16 mpg is attainable but done with an egg under your right foot…good luck. Best bet is a 3-speed overdrive standard trans.

 

This sounds like the perfect job for a freshly rebuilt QJet. Make sure the secondary air valve spring isn't set too loose. Use a vacuum advance distributor, single points should work fine. Make sure the mechanical and vacuum advance work as expected.

Then permanently install a vacuum gauge in the cab connected to full manifold vacuum. Watch how it responds to changes in throttle position and engine load. Learn how to drive, when possible, while keeping the highest possible steady vacuum reading.

Someone here will come along with better cam choices than I could suggest. Though you might consider installing it a few degrees advanced for better low RPM torque. But remember that at speeds around 50 mph and above you'll be dealing with the aerodynamics of a brick.

(Gotta learn to type faster . . .)

 

put the 4bbl on it, drop it in an early Corvette, and get 20 mpg.

 

I would not go with either stock cam shaft.
Cam design has come a long ways since the 283 was a new engine .

I doubt your going to see any drastic gain MPG wise with any flat tapped cam and carburation choice .

Choose a cam thats going to be correct for the speed you drive and the gear ratio you have . If your not going to wind it it trying to make HP up top then no need for a cam that peaks at higher RPM .

A set of aluminum heads that allow higher cc impression and a optimal deck height will likely yield better MPG .

Also are you planning on running regular fuel or premium??
Most times the engine that runs on the $1 a less per gallon fuel is the most cost effective option as far as cost per mile .
A 11-1 engine will make more power/ go further per gallon if the gearing is optimal but if its $1.00 PG more the 9-1 engine might be cheaper to drive with less HP and MPG .

The 283 is not really a torque monster with any cam . The short stroke means there better at a higher RPM so honestly id be looking at a 307, 327 or even 350 woth more torque and higher gears they can pull.

 

Call the tech/sales line of your desired camshaft company and tell them your build goal. They'll ask you to share what vehicle, drivetrain specs such as trans type and rear gear ratio. They'll then recommend a grind or perhaps offer a custom grind to meet your end goal. Along with the cam recommendation they may insist on a gear change for optimal performance (mileage) if they can't work around it.
Personally, I've had great results in the past with Schneider here in San Diego.

https://www.schneidercams.com/contact-us.aspx

 

I second the Qjet, best of both worlds. If it was mine I’d talk to my favorite cam grinder, give them all the details tell them what you want to accomplish and they will recommend the best cam for the job. I’d also run dual 2 inch pipes with you choice of mufflers (gl*** packs?)
Sounds like a fun project.
Dan

 

Man I type too slow, I’ve had excellent luck with Schnieder cams also.
Dan

 

Well sure . . . But how are you going to haul 4 x 8 sheets of drywall???

 

Stick a 327 crank and 307 pistons in it and call it a stroker motor that along with the right heads and a spread bore carb and even a 300 hp 327 intake will pull decent gas mileage and have decent low end torque. I had one we put together for a 70 C 10 that with a SM465 and 3.73 rear pulled 16 mpg on a road trip to Texas and I wasn't babying it. If I had stayed under the speed limit I probably could have pulled 18.

I like the quadrajet carbs because the small primaries are good on gas in most cases and when you do stomp on it it won't give you more air than the engine actually wants but can flow a lot of air if the engine calls for it. I'll probably run one on my 292 six rather than a 500 dollar smaller total cfm carb.

 

If it's fuel economy you are chasing, go to an overdrive transmission with converter lockup (700R4).
These type of transmissions have played a major role in fuel efficiency gains. Doesn't hurt drivability either.

 

my 396 equipped truck gets 10 mpg. I don't take it on 5000 mile road trips.

 

My combo I’m using is a .030 over standard flat top piston. Thin shim head gaskets, melling MTC-1 cam. Reworked power pack heads with a slight port.
3 deuce set up using Rochesters.
3 speed OD trans.
High teens, low 20s mpg would be great.
My current beater gets 6-7 mpg so anything over 10 seems like a win

 

Around 1980, I put a 283 together with a cam similar to the .433 lift one you mention. A 450 Holley carb that they made in partnership with some Japenese company adapted to an iron Quadrajet manifold. It went into a mini-truck with 4.10 gear and short,14" 60 series tires. It was hooked to a Saginaw 3 speed with overdrive. It got better highway milage than the 4 banger ever did (mid 20s, I believe).

Gary

 

MTC-1 specs

 

Small bore head gaskets? If yes, from whom?

 

Well, not really but smaller bore than the composite ones with my gasket kit. A lot thinner
Felpro 7733 sh-1

 

This photo is almost an exact replica of my friend’s high school 1957 Chevy Bel Air Hardtop. It was stock looking, but had the most modified motor of all of our sedans. And it was fun to drive with the installed 4 speed stick transmission.

Hello,

My friend’s 57 was the highlight of teenagers doing all they could, with the skills learned from early on in hot rods. We had the mechanical skills and a taste for high performance. Once that accelerator was pushed, there was no going back to stock, despite what car it was.
283 two barrel 185 hp
283 four barrel 220 hp

A 283 SBC motor with a two barrel carb came in a lot of stock Chevy sedans in 1957. The base model was 185 hp. The upgrade was a 4 barrel carb with the same internals. That came to 220hp. So, as minimal as 35 hp is or was, it certainly had more power. The dragstrip times were lower and the 0-60 times were also quicker. So, that was the easiest add on horsepower gain we could think of as teenagers.

My friend had a 283 with a two barrel. At the time he did not care if is had a two barrel, it was a daily cruiser and it got him everywhere he wanted to go. So, for a few months, he drove all over the place from the beaches, cruising around our local Bixby Knolls area and up into the mountains for a different environment. Enough power to get us there 40 miles away at the beach cove to 7000 feet up into the mountains for a thin air cruise.

The 57 Chevy was a 3 speed stick shift 283 stock as if it rolled off of the factory ***embly lines. But, as a teenager, it was a couple of years old. The price was right and at least it was a stick shift model. Cruising around was the highlight of our days and nights in Bixby Knolls. It was stock and so was the gas mileage for the 2 barrel. The 3 speed helped and he also had a 3:55 regular rear end gears. So, our cruising was done with little pizazz other than it was a white 57 Chevy Bel Air Hardtop. It ran fine and had some power. But, the two barrel was lacking that power needed.

He had a job afterschool and needed a good reliable car to and from home to school to work to home, plus the cruising scene on the weekends. The 3:55 worked well. When we put in my 4:11 Positraction complete third member, it made a difference. Better traction, instantly and alas… worse gas mileage around town. But, as I mentioned, gas mileage, was the least of our worries as teenagers. So, he bought a new 4 barrel carb set up and wow, what a difference in power for everyday driving and the weekly Cherry Avenue Drags location late night runs.

It was also one of the teenage cars parked in the prime location across the street from our high school. Almost every student that parked on that side of the school, walked by before school as the entrance was across the street.

So, the battle for the prime, top 3 parking spots was always a “race.” No one wanted to get to school early, but, in order to get one of those spots, one had to be somewhat early. My old flathead sedan delivery was stock looking on the outside and as slow as mol***es, but it was the camaraderie of teenage friends walking by and stopping to say hello, was the key. Countless boys and girls walked by and waved, etc.

Jnaki
Several days, we took his 57 Chevy to the beach. He was a good high school team swimmer, but after going out three times surfing, he gave it up. So, he concentrated on his 57 Chevy.
The 57 Chevy was the primary Christmas Tree delivery method for two seasons during our high school cruising days. It was a hit when it was parked in the lot and during deliveries. We always made it a point to cruise in the restaurant driveway next door to the Christmas Tree Lot. It had a huge set of 10 foot tall windows. The giant windows of the restaurant showed all of the teenagers having breakfast, lunch and dinners during the year. Even the local parents like the delivery method. Ha!
He really wanted to paint the 1957 Bel Air hardtop Red, but he decided to spend his money on go fast parts and equipment versus spending the cash on a new paint job. At Christmas, that vision would have topped off everything. a red 57 Chevy Bel Air Hardtop rumbling up to the driveway with a tree strapped to the top!!!

The 57 Chevy sounded cool with the flow through Hedman Headers and modified 283 motor. We kept going as the funds were available, so a 4 speed was added, and a dual quad set up from a Corvette was also the most significant add on item. Then a Duntov Cam and lifter kit, plus port and polish were also added to create a very quick Chevy Bel Air Hardtop hot rod sedan. He did not race at Lion’s Dragstrip, but the local late night “Cherry Avenue Drags” location was a short drive from his house.

One can wonder how all of the mods were done as a teenager. My friend worked after school and his job paid quite well. He was a hot dog maker. Not in a hot dog stand or restaurant, but the actual meat company warehouse located near our high school.

It was a process and watching it being made, we knew why he did not like hot dogs grilled or even with added chili. If one counted what was being ground up to make the “meat,” then it was a hard decision that our noses would take into account when the barbeque grilled hot dogs at parties were floating in the air.

Note:

During the 1961 Summer, I can remember the teenage days that my friend and I drove a 60 Corvette around for a day or so. The owner wanted to exchange the dual quad carbs for a single 4 barrel. He got tired of constantly running a dual quad system. So, a simple 4 barrel was now sitting on top of a 283 motor of my friend’s 57 Chevy Bel Air Hardtop.

A simple swap of both carb systems worked out well for both owners. The 57 Bel Air was fast before, but now, it was so much faster with the dual quads. Although we liked riding/driving the Corvette, it was not for us. We liked his 57 Bel Air Hardtop Sedan and my 58 Impala with the 348/C&O Stick Hydro set up for our daily cruising… The dual quad system made the gas mileage dropped from good to no so good, but the cost of gas was so low, that it did not matter to my friend. But, the power was so much more… YRMV

 

Those 2bbl 283's didn't do terrible with the land barges they were pushing. Best economy is in your right foot.

 

If you’re looking for fuel efficiency, you better go with a 2 barrel carb and maybe an RV cam (sound good)

 

Hello,

When the owner of the 57 Chevy first got his car, it had a two barrel carb. It was ok to drive to school and to the beach, but was lacking in power when we took it uphill to the local mountains for a Christmas holiday teen gathering. The long, steep, curving road kept wanting to push us back with gravity and the two barrel carb on the stock 283 strained to get to the top of the sloping grades. Plus, there were 4 of us.

When we went around a sharp curve and it was at the low end of the slope, now the car had to be in first gear with the long uphill power totally strained as one chugged up the hill. For that first time up the local mountain sloping road, it was not a fun as it should have been.

The two barrel carb is ok on the streets if one does not want power on acceleration. Pulling a small trailer? Not enough power. Loaded with suitcases and vacation gear and teenage friends in all of the seats? Difficult accelerating to say the least. Good gas mileage, excellent... we weren't worried about gas mileage... but, the whole scene lacked something...

Jnaki

But, if you are using it as your daily driver to go to work by your self on normal level surface streets, then it is satisfactory. Not wonderful, but satisfactory. A little blahhh, but it will get you to work.

Note:
The following year, we took my 58 Impala with the 348 motor up to the big Christmas teen gathering, up the steep sloping road to Big Bear Mountain for the week. YRMV

 

The Q-jet 4 barrel is a better choice than 2 barrel. The extra small primaries on Q-jet are better for fuel atomization at low throttle. Just keep your right foot out of heavy throttle. Like no more than half throttle so secondaries don't open.

The other bigger factor is engine rpm and speed. A big reason new cars get good mpg is the tall effective gear ratio with OD. Speed not only increases engine rpm, but the big influence is aerodynamic load. Aerodynamic starts having bigger percentage effect above 60 than below that speed. Lowering your car has slight benefit for reducing aerodynamic drag.

 

I would look at an edelbrock streetmaster or sp 2p(somewhat controversial)intake manifold , r even the stock 4 jet intake, with a 4 jet, early afb or holley economaster for induction

 

Efficient engines make more power with less fuel thereby getting better mileage .

 

Doesn't matter what you do. Just add 5 MPG like everyone else does when bragging about mileage.

 

Q-jet with Edelbrock SP2P intake, it has tiny port runners. And fine tune the cruise air/fuel ratio to 16:1 using a O2 monitor. The later model Q-jet has adjustable part throttle that can be adjusted without removing the top of the carb.

Another carb option is the Dual Jet and corresponding factory intake. These were used on late 70's 267/305's if you find one. It's the front half of a Q-jet, and were designed for economy.