The Stovebolt Site Forums The Shop Area The HiPo Shop economy, your opinion

which engine do you think would get better mileage, 1956 265, 1970 350, 1958 235? Mated to T-5 and 3.42 open rear in S-10 chassis (working on rat rod), have several motors laying around. I'd like to stay low on investment, so carbed, maybe elec ignition, but no aftermarket fuel injection or anything. Hoping for around 18-19mpg.

I would bet that the 350 would be the easiest to squeeze mileage out of, then the 235 and the 265 last.

For economy it's hard to beat a turbo diesel. You could see mid 20's or low 30's MPG with the right engine and gearing in a small truck.

Why would a 265 SBC be the worst choice for economy?

You can get 18-19+ out of all of them. All factors being equal. As far as the 350, it depends on year and HP. The 1970 would be pre emissions and would probably get good mileage. But a rat rod is a hot rod and hot rodders don't get good mileage except with their right foot. If you are a "smoothie" Hot Rodder, you will be OK. EFI does not give mileage. The wrong carb/adjustment/brand= BAD mileage.

I'd say the 265 would get the best mileage with that gearing.
An aluminum intake with Q-jet carb & HEI. wood work slick. If you want a lot of power to show off the 350 would be awesome.

I have often thought of a 265 with a throttle body off a 4.3, electronic ignition and a 700R4 trans and a different ration rear end. Another I was thinking of was a 4.3 with a throttle body, 4l60E transmission, and a rear end. The 4.3 setup delivers 17-21 mpg on my 1994 1/2 ton.

Lots of engines will give that mileage but he has the three mentioned. Two V8's and a straight 6. The 265 mileage is lower than the 235 and 350 and may not achieve 18-19MPG like the other two. All gearing the same. etc., after reading some original mileages given, I have to say the 235 is the most likely and the 265 is the least likely to get there. The newer V8's get past 20. That's technology for ya. Remember, gas mileage is almost the most "exaggerated" subject there is on the planet.

well the stock 55 I had with the 265 and power glide would get

17.999999999999999999999999999999999999999999999999999999999

this would have been back in 61 when we did not think of it that much........

There's a joker in every crowd.

it is true,, just like this one it was mint, made 2 round trips to Long Beach, Calif from Tx
paid $650 for it, got out of the Navy in 63 and traded it in for our first new car
a 63 corviar..

I believe you. That is pretty good mileage. Bet you wish you still had that one. We all have two or three we wish we still had. In my case it's a 1934 Plymouth coupe with rumble seat (my first car at 15, $90 in 1961). Complete and running good, a 1956 Chevy 210 and a 1967 Mustang.

one like this would have been my first, back in 59 and to stay on topic I have no idea about the gas mileage, it had a 49 merc engine..

for sure Bart, I can think of many that I would like to have back.. the 52 I just sold and my 52 truck prior to that

About a 1000 factors to consider but one thing is for sure, a smaller displacement engine will get better mileage if both the larger and smaller are of the same design. If a 265 has the same internals as a modern engine like modern oil, ignition, low friction rings and valve train, and run at a higher temp like the newer ones then IT WILL get better mileage figures. The 235 has a lousy fuel induction system and exhaust but was a great engine for it's time. With the siamesed ports on both intake and exhaust it's limited on economy improvements. Of course if half pedal will give 70mph with a 350 and it takes 3/4 pedal to do the same with a 265 then throw all the above out the window.

Finished building my 51 Chevy/Shortbed last year, drove about 1500 miles this summer. My set up is, 4.3v6 Throddle body fuel injection, 700r4 Trans., 272 rear/end highway gears. At 60 miles per hour she will run around 1900 to 2100 RPM consistently gives 23 miles per gallon. Needless to say I am very happy with the power and performance of this build. Its just so much fun to cruise with it, highway or back roads.