The Stovebolt Site Forums The Shop Area Engine Shop Changing out from a 235 to a 283

Hi guys,,
Have a 1962 C-10 235 short bed fleetside with the SM 420.. Changed out the rear end and put a 12 bolt 3.07 R&P one legger in the rear end.. I pulled from a 69.. Pretty much bolted right up.. Aren't Chevy's awesome..??!!
The truck runs great now.. And about as problem free and efficient as I'm gonna get her.. But I'm not totally happy with the gas mileage.. You would think it would do better then the 8 cylinders but truthfully it does worse.. I think it's because it takes a lot more work from the smaller motor to push all that steel.. My friend drove his 59 chevy panel from San Diego to LA last weekend.. He got between 17 and 18 mpg with a 350 and a 2 barrel carb.. My truck would have done 12 mpg maybe..
Anyone have any thoughts on this? Anyway, I thought a nice small block with a two barrel and a different transmission might do the trick.. I know it would definitely push my truck along a lot easier then my current set up..
I think I want to get a 283 with hydraulic valves and not sure about the tranny yet.. Any suggestions would be appreciated..

Put a small v-8 in & leave the rest alone. The 3.07 rear end is the right ratio for it. An o-drive would not be worth putting in unless you had a strong 350 engine. A q-jet carb is good for gas mileage. An HEI dist helps too.

Thanks,,
Can't use the sm420 i currently have.. I don't believe it will bolt into the 283.. So definitely need to get me a good tranny to.. Not sure what to get.. Any suggestions?
Thanks for the carb tips.. is the Q-jet a 2 barrel??

Hy Richie Blue, the sm420 will bolt up to the V8 if you use the correct bellhousing. I think your truck uses a hydraulic clutch, so that bellhousing is a little more difficult to find, the clutch fork comes out the right side of the housing on a hydraulic clutch. The q-jet is a four barrel carb, but a good mileage carb.

Thanks 3B.. yes I do have a hydraulic clutch.. Not sure what to look for as far as bell housings.. The 420 is a great tranny for sure.. A bit barbaric but none the less pretty solid.. So I'm not oppose to keeping it if It's the best choice for my application..

Yes, it does bolt up. I've got a 350 in front of my SM420 and it does a beautiful job. That is one stout transmission. It does feel like it's about one gear short, and that's probably because the first gear is a 7.06:1 ratio. You can probably almost walk faster.

The bellhousing was from the early 70's. I think it might be a 292 bellhousing, but not sure. It's iron though. It has exactly the same spacing from the back of the block as the original 235's bellhousing had. I used a 1968 Corvette clutch because I had a '68 Corvette flywheel. I did use the original 235's clutch fork. It fit in there just fine.
Yes, it works great.

My 235 I used to have, got a solid 16 mpg though. I experienced a huge improvement after swapping the stock Rochester 1 bbl for a Holley/Webber 2 bbl carb. I also recommend the Pertronix conversion for the points.

But if you're going the 283 route, that's a good little engine. Know what though? A 305 might offer better low end torque, and they're a dime a dozen. It's a 3.48 inch stroke compared with the 2.83's 3.0 inch stroke. But if you have a 283, it's a good motor, go fer it.

Hot Rod Dad.. I have to be honest with you.. I have nothing against the 235.. It's like working with stone knives and bear skins.. I love the simplicity of it. I can take the whole engine apart and put it back together with my eyes closed and it won't die even if i'm trying to kill it.. That being said, the only issue i have with it is that i'm [censored] off the 8 cylinders get better gas mileage then me.. I have the one barrel rochester call out on it. That carb seems like it was made with a hammer and a chisel.. No tolerances, leaky and a giant .56 thousands jet that you can stuff a pea through..
I found a rochester 4 year carb they used on the c-10 up until 1974 i believe.. one barrel with a manual choke.. it is what they call a mono jet (which i believe means it's adjustable).. So you can lean it out as much as you need to. Plus I'm sure the tolerances are better and i'm sure it doesn't leak as much as the 62 call one barrel..
It has the same exact bolt pattern. I thing I could block the extra vacuum hoses and replace the linkage with a cable.. This is one last thing I was going to try before the 283 motor.. This 2 barrel you speak of sounds tempting as well..
Have you ever tried to use later model one barrels?

i'm going with a 235 swap from a 216, but if i don't like it for some reason/g mileage, i have a rebuilt jeep 304 in the basement that's ready to go. i like it in my cj7 with a holley 4b, but it hasn't been a daily for quite some time, and i don't remember the mpg

Oh, incidentally Hot Rod Dad, I did upgrade to the electronic ignition and the converted to generator to an alternator.. Running 235 75/R15's..
So I have done all the indicated things for fuel economy.. I really think it's that rochester 1 barrel carb.. But can't be sure until I try something else.. You think those 2 barrels gave you better fuel economy?