The Stovebolt Site Forums The Shop Area Engine Shop Improving Driving Speed?? Maybe to 65MPH?

Hello All, My Name is Danny I'm new here. I have just purchased a 1960 Chevy C10 Stepside with a 235 and a four on floor. I got this truck becuase my dad had one when I was a kid and well It's a sharp lookin' truck i think....Introductions aside my question is what kinda relatively inexpensive things could I do to increase top speed? ( I want around 60-70mph) I was thinking a new rear end, but what kind and from what vehicle can I use that would require the least amount of modification. Also I've been trying to identify my head casting number. any clues... #3836848 thanks all!

You have a few options. Fewer if you want to do it on the cheap. If you want to have the best of both worlds and go broke, do what I did and add a Gear Vendors O.D. You get to keep your original tranny and gears, and you can overdrive 2nd, 3rd, and 4th. I have a 3:90 rear and can go 70 mph at 2400 rpm in 4th over. Of course, to handle smoothly at that speed, be sure your brakes are good, and tall radial tires are ESSENTIAL. Another good option is a NEW tremec 5spd. A bit less than the O.D. money wise but a nice drivable tranny. You lose your granny gear, but get a nice driveable gear range with 5th gear being O.D. And if you have skills and time, the cheapest way to go would be to salvage a 5spd from a Camaro or an S-10. The downside to this is you may not know what your getting quality wise and of course, no warranty. And then there is changing the gears. Not an option in my opinion because you lose workability and the ability to accelerate nicely while driving in town if you want to keep the 235. Keep searching the archives, there is a ton of info on this. Good luck.

Welcome to StoveBolt Danny - 848 is by most guys opinion the one to have on your 235. I ran 3.36 gears in my car when it had a 235. Worked good for me cruising at 55-60.
Do you know John at www.57rustbucket.com ? He's up in your area.
Doug

Another option would be to change your ring & pinion gears to a 3.38 ratio. This is not cheap but it accomplishes what you want.

My '54s have 3.90 rear ends and I find that I can cruise at 65 mph because my tires (truck radials) are about 3.5" wider diameter than stock tires. My brakes parts are all new and all front-end parts are in good shape, so I do not worry about the higher speeds.

scout the salvage yards for an automatic truck it should have a lower number gear...doc

I like the S-10 5 speed conversion. It is reasonably easy to do & is fun to drive. The 3.38 gear set is a good way to go but is a little expensive & you need someone good to set them up. Changing rear ends in that model is kinda tough. You need a good welder.

Danny-
I have to agree with Wrenchbender here. Keep your stock rear gears and put in the 5 speed.
At 70 MPH you should be turning less than 3000 RPM and you will still have lots of pulling power.
First time you get it out on the highway you may decide to go through the front end from top to bottom so it doesn't scare the s**t out of you.
Don't worry, rebuild kits are readily available and will get everything right up to snuff.
Good Luck and keep us posted!
Guy

What year S-10? and would it bolt to the 235? What modifications would need to be made? the world of Chevy is new to me as I grew up a ford man converted to Chevy.

One thing that did help on my 235 to improve top end response was to install a 2 barrel Holley/Webber carb from Langdon's Stovebolt. Then I was able to smoothly and consistently drive it at 3800 rpm plus, taking me to around a 72 mph top speed on a 4.56 rear end. That was only for bursts of speed. But I routinely averaged about 68 mph on the highway.

There's no way I could have gotten that kind of throttle response with the Rochester 1 bbl.

easiest, and maybe cheapest change would be to find an OD 3spd, late 50's to late 60's .... straight bolt in

Bill

From any Car or Truck with a 235??? would a 3spd OD really give me that much more speed?

Oohhh yeah. Got one behind my 235, cruises fine at around 75-80 @2500 rpm with 3.9 gears and a 30" tire. Any car or truck unit will do, just keep in mind that that most car units have a speedo drive gear for a 4.10 rear gear, so the speedo will be off.

any engine ... the OD gives a 0.7:1 high ratio

Bill

There has been a world of info on the T-5 conversion on this websight. Check the tech. tips & do a search. 87 on back is the best one. It has the mech. speedo drive. If you have a electronic speedo you can use the 88 up.

Since you currently have a 4 speed trans, any transmission conversion will also require a driveshaft modification. Fred

Hey all. Not to steal the show or anything, but I've been wondering pretty much the exact same thing as Danny -- I've got a 65 C10 with the 230 in it. Everything is original, but it just seems to really work the motor on the highway. Is highway speed too much for that motor as it is stock? Or am I just not used to hearing what a stovebolt sounds like on the highway? Keep in mind this is the first straight six I've ever owned...

Dearth, the main problem w/ all these ol 6's on the highway is the rearend gearing - you've prolly got a 3.90, which will put any engine up at it's max RPM above 60mph, so yes ... they all sound like that stock

Bill

Something that you have to keep in perspective is these trucks were built as work vehicles and the highways weren't as fast as they are today. The second thing is that who would have thought they would last this long - certainly not GM, they like to sell new ones. If you want to compete with the crazies out there you have to upgrade to an overdrive or better set of gears. It's also a good idea to update the brake & steering systems.
Fred

I think the easiest and cheapest would be to pick up a set of 16" wheels and a decent used set of LT235/85R-16 tires for it. If you're running a 4.10 rear end,you'll be running about 3,110 rpm at 70 mph,that comes down to 2,900 rpm at 65 mph. You'd probably be into it under $200.00
Speed

yeah my rear end is the 3.90. I was thinking of going down to a 3.38 ratio rearend. I'm just still kinda torn between the 3 spd OD or the rearend, I'm crunched for cash and only would want to spend about 500-600.00 on this.Plus I would think putting a rear end in would be less time and labor wise as a tranny But the thing is I have time on my side as my truck drives beautifully right now in the city. Anyone know out there about what I would be spinnin' RPM wise at about 65MPH with the 3.38 rear gear?

What size tires are you running?
Speed

That’s true Dad,
In ’63 I had a ’60 Biscayne, I was a budding parts man for Chevy and scrounged a GSD’d intake and carter four bbl carb. Milled and brazed the manifold up to take the 4bbl and it really improved the top end. Didn’t improve the lo-end and I was told by some old timers that if I wanted low end response to go with multiple carbs instead of the single one. Never tested that theory out.
By the way, what tires you running on your 3/4 ton? I have a ’50, 3604 with 7.00x15 two pc rims, 4speed and rear is of course the stock 4.57 and at 60 she’s just screaming. Don’t have a tack so I don’t know what the revs are.

Beg to differ with ya on the highway speeds, back in the day. I was a teenager in the 50’s-60’s and the hiway speed were 65, anyone that could, drove faster than that though, just like today. I got a couple of speeding tickets every year because of it, but back then ya just went down to the judges office and slipped a couple of bucks under the table and the ticket disappeared. I remember when they dropped the speed to “stay alive at fifty five” and every one *****ed about it, just like they do today.
Of course you’re right, we didn’t have the super hiways and we didn’t consistently run 80-90 mph like we do today.
Denny Graham
Sandwich, IL

I've got GMC chrome wheels from the year 2000, running a set of modern Uniroyal steel belted radial 235/70R-16's if I remember right. That alone made it feel like I wasn't taking my life in my hands over 45mph.

I have the same rear end ratio as you, and picked up a small tach and mounted it to the steering column. It is electronic, so it wires up to the distributor.

According to my tach, at 68 mph, I'm running about 3500 to 3600 rpm. I dared not rev it above 3800 rpm, even though with the Holley/Webber carb, it wanted to. And that took me to short bursts of speed at 70 to 72 mph, so that I could ALMOST keep up with traffic.

My 235's got a crack in it. Still runs, but I only can drive it a few miles at a time with fresh (cheap) oil in it, because after 5 miles, it's mixed with water. I could re-sleeve the block, but it's not worth the money I'd have to spend to rebuild it. So I'm trading my 235 for a Napco 4WD set up.

I'm currently planning on building a 400 for it. I thought about converting it to a 292, and that would be cool too, but I already have a spare 400 motor, sitting in storage. For rear gearing, I'd like to get something taller. Probably a 3.73, because even with a V8, 4000 rpm at 75 mph is really buzzing the motor.

two questions on the GMC wheels, did you have any trouble with the center hole regestering on the hubs? the newer Chevy center holes are to small to fit over the hubs. And how bout the offset clearance, seems like all the newer rims have more than a 3" offset?
Denny Graham
Sandwich, IL

At 68 mph,my GMC runs 2100 rpm.
Speed

Speed, that's pretty good. What's your combo? I get 2400rpm at 65 in 4th over, and 3000rpm at 65 in 4th. And for the 1st time I really revved it today just because of this post. I hit 60mph in 3rd over at about 3800rpm. Of course this is all possible because of my new tach

Wow! a cracked 235 for a Napco setup? Good job! That's got to be the deal of the year!

I thought so.

My 235 ran EXTREMELY well up until it failed. He's been in it and was impressed. I think he wants to use it for parts, since the rest of the engine, block notwithstanding, is still quite good.

It's got a nice carb set up that he wanted. I was going to trade just the carb with some money, but I think I'll give him my original rear end when I swap over to the Dana 60 in addition to my 235. Mostly because he could use it, and I don't really have a place to store stuff.

The three speed with the overdrive is probably the easiest and you keep your rear gear for loads or trailer pulling. It's pretty much a bolt in and you can hit the "search" icon and get alot of input on it. If your rear is a 3.90, when you dropped it into overdrive it would give you a 2.73 final drive ratio--a real cruising gear.