Hi all. I bought a '62 235 of craigslist. It's got a Patrick's cam and I'll be putting in Fenton exhaust and an offy dual carb intake. I have '57 3 speed overdrive for it and it will all be going in to my '52 styleline. I am looking for info on rear gear ratios. I'm a math teacher, so I can work out all the speeds-at-rpm's and such, but I just don't have the experience with 235's to know what rear gears will impress and which will disappoint. I live in LA and will be driving in both stop and go (0 to 50mph) as well as highway cruising (70 to 75). I'm not trying to make my car a speed demon, but I don't want to bog down on my daily commute (which includes a large 5% grade climb) either. From what I've read, S10 4x4's are often loaded with 3.42's, or I could find a '57 powerglide rear with 3.55's, or I can change to 3.73's, 3.90's, or 4.11's in either axle. I am wondering what axle ratio will give me enough acceleration without buzzing around uncomfortably. I plan on using 26-27 inch tires. If you've had any experience with a similar setup, I'd love to hear about it. Thanks
My high school 54 Chevy came with 3.78s with a 3 speed. Make sure you have intake heat or it will be terrible to drive around in town unless maybe you live in Arizona. It was bad in Fla and I had to figure out a way when I put the 2-1s on it. You can get away with higher gears with an automatic & a torque convertor
10 bolt from a Camaro or Nova will go right in if you knock off the old spring perches & weld in the appropriate ones for the narrower springs. BD code 10 bolt comes w/3.36 which should work well. Casting codes
I ran a 235 with a saginaw 4 speed and 57 with rear 3.55 gears in my 40 chevy and it was great around town. A little buzzy at freeway speed but no OD. I would be thinking T5 trans and shorter gears if I was to do it again.
all great responses. Please keep them coming. With the overdrive I end up with the following gear ratios 1st 2.94:1 2nd low 1.68:1 2nd high 1.18:1 3rd low 1.0:1 3rd high .70:1 My rear of preference is 3.55, so has anyone struggled up hills with this at 75?
Been through this about a billion times. It drops in without the changes - the pins locate it, where's it going to go? If mine acts like it wants to move around I'm just going to put a filler block in there.
My 54 has mildly built 235 single carb split exhaust,61 car 3spd. I run a 70 Nova 10 bolt with 2.73s in it. The motors pretty torquey so its OK around town and flys on the hiway. I can cruise 75 comforatable all day. I think 3.08s or 3.23s would be the best of both worlds and a bit more practical.
Drove a '55 for a while with a 235, 3 spd with overdrive, 4.10 gear and 30 " tires. Did well but seemed to be winded at about 65 mph. With 30" tires I'd reccomend 3.73 gears. With 26-27" tires the 3.55 should do fine. The 3.73 might be winding a bit tight at 70, and the 3.55 might load down a bit on long steep grades. You can have anything but you can't have everything.
Wow, 2.73's? And you don't bog down climbing hills? With the overdrive, I should be running about 2400 at 75mph with 3.55's. 2200 at 75 with 3.42's. I wasn't even considering going lower than that. I didn't realize these motors had enough grunt for that. Where do you find your torque kicks in? I may have to rethink what I was considering my comfortable cruising range, I was thinking the 2000-3500 range.
Ya I was suprised. It will pull most mountain passes here at about 55mph with the foot on the floor. I usually stick it in second early and keep it under 3000rpm, about 50mph on long pulls. Like I said 3.07s or 3.23s would be optimal for all around driving. BTW I run 205-75-14s about 26" tall. Oh and it loves to sit about 2300-2500rpm, pulls about 12-14" of vacume there and gets 19-20 MPG. I live at 3000ft above sea level. When I get to the coast it pulls noticably better.
http://www.onlineconversion.com/bigger_tires.htm Here you go, play with these, FWIW, I run a 3.90, '62 3sp+od, '56 235, 31 inch tire (215 85R 16) in my '49 Chevy 1/2 ton.
Those calculators are great cosmo, and a great resource. I would suggest that people looking to make changes with any old cars bookmark it. But I'm a math nerd, so I already wrote programs for my graphing calculator that does the exact same thing. I know what speeds theoretically happen at what rpm, I have even graphed it out with different rear gears and tire sizes for comparison. I guess what I really need to know to map it all out is what is the sweet spot for these motors. I was thinking it would be from about 2000 to 3500 rpm, with torque peak at ~2300, so I should try and keep most driving in this range. But like I said, I don't have much experience with these motors.
I have a 55 Chevy pick up with 3.9:1 rear end and run 235 75 15 tires on 8" rims and the engine has an HEI ignition, Fenton cast iron headers and a Clifford intake manifold with a Holley 390 CFM four barrel carburetor. In third overdrive at 70 mph I am turning 2300.
You can drive it anywhere any time and as far as you want to go but it might just take a bit longer than in a new rig. If the engine and whole drivetrain is in good shape I don't see a real issue. It's when you start cutting corners and trying to run tired components that you run into trouble.
Anybody got an opinion on what rpm range the 235 is most comfortable running in? Because of the overdrive I've got a pretty good ability to cruise and acceleration shouldn't be bad, but I want to tune my cruising speeds (mostly ~45mph in town and 75 on the freeway) to the most comfortable range, and I want the car to be able to cruise straight up the local hills without needing to move into the truck lanes.
Depends on the cam. You mentioned Patrick's cam and he likes to sell Delta's 'Bulldog' grind, with peak torque around 3000 rpm. But maybe you have the 261 cam that was stock in the later 235s. You get best mileage around peak torque and the late 235 with stock 261 cam and good breathing really likes to run smooth and quiet around 2500 rpm. Maybe not the best cam for an overdrive on the freeway, but your car is relatively light around 3000 lbs. I have stock 3 speeds and 3.55 rear and 28" tires on both my rides for over a decade and it's all I'll ever need for street and freeways.
Yeah, I was told it was a Patrick's cam, but the specs are unknown to me. The motor is in the car now with the original 3 speed (not the overdrive) and original 4.11 rear axle with "torque tube" or whatever the enclosed driveshaft is called. It runs fine, idles easily at about 800 un-tuned. Not particularly lumpy, so I don't think the cam is too far from stock. I was hoping that would mean the torque peak was closer to 2300 than 3000, but like I've said before, I don't have much experience with these motors.
I don't mind cruising at 2500 if that is what the 235 likes. That would mean using a 3.73 gear with 26-27 inch tires. Should make climbing/accelerating easier.
I got a 235 in a 54 210. 2.93 Nova rear. 3.50 1st Saginaw. Howard#7 cam from patrick's. Fenton, 2 RochesterB's. HEI. There's nowhere I can't go on the highway and have to downshift for hills. It pulls like a freight train. It will walk away in 4th from 1000 rpm. 25 mpg for highway mileage. will cruise all day at 70-75. Solid lifter cam, it will spin to 6000, but runs out of steam around 5000. But is real happy running between 2500 and 3000. The little motor is real torquey. It's a pleasure to drive. It's not a rocket, but will keep up with traffic. And go around the smog mobiles on hills. And nothing else sounds like a 6. frank
Take it to a dynamometer and see exactly what RPMs it likes. Put a vacuum gauge on it to see where it will get the best mileage, too. Play with the timing and the carburetor a little bit. No risk of guessing, bad advice or wasted money on the wrong parts. Costs around $75 to $100.
That sounds great pumper. I was under the impression these motors didn't like to spin over 4000. Must sound incredible. The vacuum pump is also a great idea wsdad. I'm a teacher, so dyno time is an expense I'd like to avoid. I know my combo isn't all that odd, so I thought first of polling experience around here. I already have the 57 3 speed with overdrive, so I will be using that. I was going to go with an s10 t5 until my Dad stumbled on this 3 speed overdrive. I love the idea of keeping the column shifter and the thing sounds like a kick to drive. Plus then the wife can sit next to me on the bench seat without having to have a shifter between her legs.
Re-reading that last post makes me wonder... Maybe I Should position the shifter between her legs... Sounds like it might be more fun to drive.
Even if you go a little over or under on the rear end ratio, the money saved on the dyno could be used to purchase new gears once you drive and get a feel for your own car. Plus, there's a good chance you may hit the bull's eye the first time with a little advice. That makes a lot more sense.
I may very well choose to go to the dyno later, but not for now. I plan on going fuel injected with megasquirt when I go to the offy dual carb intake, so dyno time makes sense then, but for now I'm looking at numbers, charts, and data in order to make my best, well educated, and hopefully informed guess. If I don't get the rear ratio exactly where it needs to be the first time, swapping in new gears should be cheaper than the dyno time I would buy before installing my throttle bodies, computer, hei, etc. I have to believe that people on this site have enough experience with these motors to know where the sweet spot is for near stock cams, a set of fenton duals, and a dual carb intake. It's just too common a setup. My Dad's got several friends who have rodded out tri-fives, he's going to see if anyone's still got their old powerglide axles. That would fit nicely and the 3.55 gears I had planned still sound best from what I am reading. Please let me know if you disagree.
I was running a 235 dual carbs and split exhaust with a saginaw four speed and nova rearend. 80mph down the freeway was no problem......
What SIZE would 27-28" tires be, Teach? I'd look for a '55-'64 housing, as the pumpkins are a pure drop-out - NO c-clips to fool with as with 10 or 12-bolt diffs. Stock ratios are 4.11 (OD cars), 3.70 ('55-6 sticks), 3.55 ('55-6 auto, '57-up sticks) 3.36 ('57 auto), 3.08 ('58-up auto). I think a 4.11 or 3.70 would be a good place to start. I wouldn't go taller than a 3.55, depending on tire size. Pumpkins range in price from 50-$100. I have extra axles and housing, several pumpkins - need to go and check the ratios. Usually, the tooth count of the R&P is stamped on the outer edge of the ring gear, next to the PN. PM me if I can help with parts - I'm in El Cajon. Check with Patrick about the power range of his small cam, which I think you have. I'll guess it runs from 1800 to 4500 RPM. Having driven cammed 235's for 30+ years, I'd say the sweet-spot would be in the 2250-2500 RPM range, with plenty of pedal left for freeway passing. Max torque stock was at 2400. At 45 MPH, what gear ratios would put you around 2500 RPM in 2nd-OD or 3rd-direct? A buddy has OD in his '65 Stude, takes off in 2nd with OD engaged, shifts once to 3rd. The OD does the work like an auto, pretty cool!!! Be dang sure to HEAT THE INTAKE - water or exhaust, doesn't matter. Without heat, I ALWAYS had a flat spot off-idle. A water heat kit from Tom Langdon cured it, only need to drive 3-4 blocks with the choke on. Clean and lube the mechanical advance in the distributor, check vacuum advance as well - use manifold vacuum. Better yet - check out Langdon's HEI dizzy for the 235, with vacuum advance. Uses .060" plug gaps for better mileage and power. I run 10 degrees advance on 87 gas. Hook up a tach and vacuum gauge before you start tuning for the road. MAKE ONLY ONE CHANGE AT A TIME, take down good notes, record fuel mileage with an accurate odometer. Finally, keep in touch with us with your progress! We want to know "...the REST of the STORY". Should be a lesson or two for the troops here who LOVE them ol' sixes!!! Good Luck, Tim
Sounds like theres a few guys that replied here have really drove these things and know there combos. Ive built about a dozen of these motors with different mild combanations and they all have a definite sweet spot at 2300-2500rpm. Anything over 3500rpm seems to be a waste of time. Manifold heat is a must. The combo in my 54 car has been my daily driver for 5 years and gets 15-20k a year on it. Like I said a little lower than Im running would be perfect. Gas Pumper is on the right track too. I think 3.08s or 3.23s would really work well. My dyno is miles of open road a tach and vacume gauge. I stick with the higer gears because I like to drive 75-80mph on the hiway all the time.
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