The Stovebolt Site Forums The Shop Area Engine Shop cruzin' at 70

Texas is a big State. In Dallas people like to do 70. My 55 has the orginal 235, transmission, and differential. What are the options of simple solutions for staying up with traffic. Or being able to cruise to Austin. Is it as simple as finding a 50s sedan (235 engine) with overdrive and changing the transmissions? If there is such a beast - Would it fit? Do I need to change out the differential gears? What have you guys done? TIA

Choices: ring & pinion change--most suppliers have what you need, rear end change to get taller gears, trans. w/OD (mid 60's trans. necessary for syncro low--coarse splines on front, fine splines on rear) or perhaps a combo.

For a 235 I wouldn't turn over 2500 rpm for long periods of time. So you'd ideally like to keep your rpms at 2500 (or lower) at 70.

There have been lots of discussions in the past on adapting the T5 5 speed tranny to the 235. And someone out there makes an expensive adapter plate that allows a direct bolt up. On the flip side there have been questions raised about it's durability and mixed opinions.

Bumping up your cruising speed is great. It'll get you good attention on the freeway. Just make sure you can stop. A thorough inspection and rebuild of your braking system wouldn't be a bad investment.

I'm glad I don't have this issue with my '66. Even with the 3.73 rear gear the 230 still manages to hold 60-65 mph for hours and 70 for short stretches. I can't wait to get the 89mm in with its .73 overdrive. I see 75-80 mph cruising in the near future.

Go back a few days and read this post
Topic: 216 top speed???
There is a lot of other things to take into consideration when you want to run at higher speeds in old stovebolts.
Myself I figure if they wanted in front of me they would have started 15 min sooner...LOL
And when they see you in your bolt you will get more thumbs up than in a brand new Duramax
The mentioned post is well worth reading before going 70 MPH........be safe

I would change the rear-end gearing and see if you can live with that.
I have a 327/th350 set-up with 2:56 rear....I can go real good BUT I gotta watch it cuz I have stock brakes and front-end. It's all in good shape,but the truck just wasn't designed to go too fast.

Well, I don't think its safe to have a truck with a top speed of 55 mph. Here in CA we have some big freeways and I am stuck in the slow lane. Sometimes I have an exit on the left and have to merge across 4 lanes of 70mph traffic. This is never a good feeling. When traffic is light this is no problem but when heavier they just don't let you in going that much slower. I am going to do the gear change on my rear end, well, my truck's rear end.

It will also let me get away from the idiots merging onto the freeway. Here I am coming rumbling along at 50mph in the slow lane, the rest of the lanes doing 70+ and some idiot merges into the slow lane from the onramp at 40. What do I do? I can't change lanes to go around him, as soon as I do he is up to speed and I never get by. I have to slow down to his/her 40mph and then when they get their act together I am back to 50.

I hate it.

Just because your truck can do 70 doesn't mean you have to. But, I would sure like the option. My F*RD does over 100 but I never tried and it has anti lock brakes.

Thanks for all the thoughts and info. Yesterday, I drove to Oklahoma (business) and was thinking. Woodhick you are right about the stopping ability, and I was not planning on changing the brakes. So a 50s truck with 50s stopping ability is scarey at best on the Dallas freeways at 70 miles an hour. But I was thinking more along the lines of Tony M. If need be, I would like to be able to zip up to 70 for passing purposes or whatever (if safe?) without thinking the whole truck is going to come unglued. Also, I was at two swap meets in the last month and the same rear end (differential) was on a trailer. It looked like it was out of a 55 (or so) sedan. I was going by the hub caps. I seen it twice (ohh, ohh) and got to thinking. I was wondering if the sedan and truck rear ends were the same width and if the gearing was different? Are they interchangable? Would it give me any advantage in todays traffic - for just being able to go a little faster? Or is it not to be? And Woodhick I did read the earlier series of posts on how fast a 50 would go (or something like that). I am still confused if this is even worth it or just keep cruzin' at 50 and stay in a 50s frame of mind.

Stock brakes in good condition will stop you just fine from 70 if they are just used for that once and then let cool for at least 2 miles. They will not work well for stop and go traffic. They fade quickly after two stops from 70 mph. Using a semimetalic lining will help but will shorten lining and drum life. I suggest you stop hard numerous times from 60 mph on a lonely road so you get a feel for how the brakes fade. You should notice that it is harder to stop but you will still be able to. Once they fade (they will start smoking too) pull over and let them cool off by parking with the engine off in gear but without setting the parking brake and let you foot off the brake. That will keep the drums from warping.
I check my car and truck's fade resistance every time I do any brake work and about every 20k miles just as a precaution. I own a sports car and drive on the twisty back roads a lot and it really sucks when your brakes fade and you should know what it is like. The idea is to know the limitations of your brakes and either drive below them or upgrade them.
(edited for lysdexia)

Interesting post , 4onthefloor ,,
I've been driving pre war chevy trucks , some with mods , for 28 years , NEVER have I had brake fade !
I'm just guessing here , , but it sounds like you are a much more aggressive driver than me .
I find that normal defensive driving practices usually get me thru the day , you know , ,watching my following distances , looking a long way ahead as well as right in front of me , planning my route , anticipating the other drivers etc ,etc .
Some days I get almost right into the city before I need to use the brakes . Heck even with the 3.9 diff , just lifting my foot off the gas ,slows the truck right down .
Ok , Ok , so we have really different styles , thats fine ,I 'm not picking on you , ,just pointing out that stop / go driving seems to be a slow process and brake fade is really unlikely .
If you are stopping hard , OFTEN , from 60 - 70 mph , then I suggest a new approach to driving style would be more economic on your trucks wearing components .

Yes, while I may drive my car aggressively once in a while, I don't drive my truck that way. I harly even use the brakes on my truck. Keep in mind too that hauling a load is much harder on the brakes. I only hit brake fade when I am trying too, I am only suggesting it here as a way to get the feel of your braking capability and determine your margin of safety. The original poster suggests that he is trying to keep up with dallas/la/boston/ny style traffic which can be stop and go where you go 70 for a while and have to slow down to 10 and then speed back up to 70 which is tough on brakes and drivetrain.

Ok 4 , I see where you are comming from ..

If you drive 70 here, you will get ran over!!!Let alone 50 or 55!

Hey, Oldblue-just a couple of thoughts. First, how about a front disc brake upgrade, coupled with a dual reservoir master cylinder? You can get them in six lug, if you want to look original.Inspect your frontend components for wear, repair/replace as necessary.

Now that you can stop better, to go faster, you need better gearing. Perhaps a ring and pinion change, then some sort of add-on overdrive unit for your tranny? I seem to remember reading an article on one in one of the old truck mags a few years back...I'll check the archives and see what I can dig up for you...

Wannabe

Hey Dennis, there is a place over in Royse City Texas that has kevlar lined brake shoes that I am going to try on my truck - they are supposed to have 40% more friction than the old asbestos cancer causers. I have the info if you are interested - its like performance dyno brakes or something like that. They were written up in one of my truck magazines.

I also am hoping to get the great rust mountain up to 70, and I thought I would put the brakes right first before I started moving it around, but the gearing issue is one for me as well.

has anyone been able to up the ratio on the rear end of a 1 ton?

This post has changed from going faster to making sure IF I AM GOING FASTER to being able to stop - and repeatedly. - Make sure it stops before it goes (GL quote). - This is good.

Next question on this train of thought. How can I check the front drums to make sure they are within spec's. If the lining of the drums are thin (from the 47 odd years of service) (and if they are original), reason has it that, there will be serious consequences caused by a brake system failure? I noticed LMC (got the new mag yesterday) has the drums for about $45.00.

If I had a digital camera I would start a web page (I treasure Mr. Laroke's) and call the old truck Don Julio or Dona Chulita. Nice spanish names for here in Texas.

Dennis,

We are driving our 52 Chevy car here in the North Dallas area daily. Fifty five on US75 does put you out of the traffic flow. We changed the rear end (3.73) and did the T-5 which gives us a steady 65 with no sweat. We also did a front disc conversion and dual master cylinder. I think stopping is more important than doing 70 mph. I used to drive my Coupe with original style brakes and it was not possible to be within acceptable safety margins. That was six years ago and the traffic has gotten worse. Just finished rebuilding the front end and that helped a lot, it was worse than I thought.

If I were going to rebuild to stock, I would buy new wheel cylinders, put in new brake lines, check specs on drums, bring the front end up to snuff and then convert to dual master cylinder as the bare minumum for driving on 635, US 75 or the Tollway.

Most of the drivers honk and wave and tolerate the slow, but they have no idea how poorly you will stop if there is an emergency. Also a worn front end will cause additional problems in a panic stop. Add a little rain, vacuum wipers, skinny tires, no signals, tiny, dim brake lights and you become a real hazard to yourself and others.

If you want to ride in a stock 235 with updated trans, rear end and brakes let me know. We'll cruise to Sonic for a burger.

Patrick

we're about due for another north texas informal meet anyhoo.

Patrick, I live in your neck of the woods (north Dallas) near UTD and will take you up on the trip to Sonic. I can use all the help I can get - and a jalapeno burger. My budget won't allow for the disc brake conversion (it looks like it would cost about $1,000). I have replaced the front shoes and plan to replace the drums and cylinders.

Thanks to everyone else for your help and patience.

Hey Dennis, I found the link, check this out for the advanced materials in brakes shoes, etc. I will probably be giving their stuff a try in my vehcile.

http://www.praisedynobrake.com/index2.htm

Your 55 2nd came with optional three speed overdrive, though they are rare. This option included a 4.10 rear instead of the 3.90. This should be a bolt in. I have run them, they allow you to cruise a 70 but are tough to find in good shape and parts are getting scarce. Instead I now use a T-5. Holds up fine behind my 6 so far. I have a article in the Tech section, no need for an adapter plate for early models of the T-5.

As far as brakes, I use the Kevlar shoes from Dyno Praise and have never noticed any fade. I have 35K on them now and they are still in good shape. I also like to run radial tires and a aftermarket sway bar. The truck stops and handles well, though I feel I am at a disadvantage compared to most vehicles, and I try to keep that in mind when driving.