6 cylinder top speed

[sawyerrm]

I'm looking at 55 - 57 Chevy trucks on EBAY and CL. They seem to be in two camps, those with original 6 cylinder and those that have a crate 350 etc. My hope is to drive the truck to work every Friday. This involves about 10 miles of SF freeway driving. Not looking for high performance but I need to safely enter the freeway and keep up with everyone ~ 65 mph.

The general question is driving a classic truck to work on Friday practical?

The specific question is do I need more power than a 6 cylinder provides.

Apologies in advance for the newbie question.

Rob

[dwcsr]

Simple answer is yes you need more power in that type of driving. what you put in is a whole another topic of discussion, If you want 6 cylinder look at a 292 in the 70's that way you can use an automatic trans or std trans and not have issues with highway speeds. 230, 250, 292 is a good swap, 350 is a very common swap. The question is do you want to keep up with the porches or not get run over by the Hyundai's.
230 to 292 is a carb engine. 350 can be carb or fuel injection. The Vortec 4200 is a great truck inline 6 with fuel injection that will give you performance and mileage, auto trans and the reliability of new technology.

[OrrieG]

235 has a redline of around 3900 rpm. The link in my signature will get you to a spec manual page. Scroll down to year index and click on the year you are looking for. In the manual there is engine dyno info and rearend ratio info for each model. With that you can find an online mph calculator and load in the rpm, rear end ratio, trans ratio at 1:1 unless you want to see want an OD auto would do, and tire diameter to get a mph.

from 76 to 80 I ran the stock 235 in 2wd. With the original rear end and three speed trans 50-55 was comfortable, 65 started pumping up the hydralic lifters (it was a 58 car motor). In 81 I change to sm465 four speed and 8 lug ton rear with 4.54 ratio because I was hauling a camper in the boonies and needed the lower gear. Highway speed went down to 45 but most of the pavement were mountain roads anyway. In 85 switched to 4wd, warmed up 283 and 3.74 rearend. Cruised all day at 75 with camper on or off, 283's don't mind higher rpm.

[wolffcub]

You don't need anything larger. A inline will perform fine at highway speeds if you just alter your gearing a bit. The truck stock i think were designed to do about 45-50 easily. A simple rear end ratio change and your good to go. If post some more info on exactly what truck / engine size, current ration and tire sizes i'm sure we can help you out better. I have a 55 235 mated to a different trans and a changed rear an i'm doing 70 (110 kph) at 2000 rpm and its a breeze. Even before the transmission change with the 3 speed and 3.73 ratio with smaller tires the truck was around 3200 rpm at 60 and it still seemed smooth but the exhaust note was loud.

[yossarian19]

When you say SF freeway driving, we both know you'll be lucky to hold 60 mph for more than a couple minutes. Unless South Bay traffic is radically different from the Easy Bay traffic I remember...

Anyway -
With 1:1 transmission gear & 4:10 in the differential, you will be running the I6 around 3,000 RPM. A bit high. You also only have ~150 HP as measured by 1950s standards. A lot less by today's measurement.
So, you *could* run either one of them on the way to work but I'd choose the V8, preferably with an overdrive transmission.

[joedoh]

brakes. brakes are how you go fast. if you upgrade the rear gear for more speed, get brakes too or you will either not stop from 65 or have a life altering experience trying to.

the stock motor should do ok at 65, if you have the right gearing. you can expect some tradeoff in acceleration if you change rear gears.

[curmudgeon]

Refer to the last 2 comments of above. I occasionally work in Redwood City and have driven my 6 cyl truck to work. Engine power is not the limiting factor, but you cannot keep up with freeway traffic with stock gearing, I swapped out my rear to 3.08 which will allow my truck to run 70-75 and stay within the rpm torque range of the 6 cyl. For safety, I also upgraded to power front disc and moved the sloshing gas tank behind me to the rear. I can now dawdle along in the slow lane at 65-70 on I-280 while everyone else blows by me at rush hour.

[MARTINSR]

I drove my truck all over California on the freeways when it had the six in it, with 3.90 gears even. "Top speed", we won't talk about that but it did 85 MPH in the quarter. At 16:40

I drive my '59 Rambler on the freeway all the time. Right here in the bay area (I'm in the East bay) with a 196 Flathead! 65 is pushing it, I usually drive about 60 the RPMs are WAY up, but I do it. If it was a regular thing I would put an overdrive in it (got one in the shed) but I usually stay here in town. It is my daily driver and have been driving it EVERY SINGLE DAY for over 4 years. But on that truck the rear end ratio as mentioned is the biggie.



Click on the image or the link to see a video.



http://vid200.photobucket.com/albums...r/DSCF0807.mp4



http://vid200.photobucket.com/albums...r/DSCF0804.mp4

I'm making fun of it in the video, but honestly, it works. I will hope on the freeway to go a 10 miles but that's about it. Any further and I am going to take a different car. But that doesn't mean I couldn't have.

I just realized something, my car had bad U joints when I took these videos! It's also with bias ply white walls. A year or so ago I put radials and at that time found that the U joints were bad! I had thought it was the tires that was causing the vibration but those U joints were the culprit. It actually cruises on the freeway MUCH better now.

Brian

[sawyerrm]

Thanks everyone for your comments. Last night I bid on a 6 cyl, 3sp with standard rear end and drum brakes. I think I would like to try adding power/disc brakes and 5 speed manual ( T5 was recomended ) and see how I do. If that's not good enough, then the rear end swap would be next. Finally, if still not happy, will add the 350 crate engine.

Thanks again for taking the time to respond to my newbie questions and to my new SF Bay Area friends, hope to see you on the road.

Rob

[MARTINSR]

But honestly, all it takes is just a little bit change of driving habits (ones that we ALL should do regardless of car!) to drive with those drums.

I drive every single day in a car with drums that don't even have self adjusters! And OMG even the single reservoir master cyl!

It actually stops damn fast. The real difference between drums and discs are that drums heat up when being used a lot and fade. That is the real difference. You would be hard pressed to drive my Rambler and my wife's mini van with discs and tell me that the Rambler doesn't have them. It stops CRAZY fast. Now my son's Falcon, they just had funky brakes and it takes a lot more pedal pressure to stop it, but they still work fine. Those too, single reservoir master.

Just service them, look them over once in a while. I go through mine and adjust them and check the fluid every year or so. I look at them more than that to be sure the hoses are good and leakage that sort of thing. But other than that, you can feel it in the pedal. Unless a hose were to just blow, you would see a slow loss of fluid in the pedal.


Brian

[yossarian19]

Originally Posted by MARTINSR

Just service them, look them over once in a while. I go through mine and adjust them and check the fluid every year or so.Brian

This is either a pro or a con, depending how you look at it. I figure, there's enough to do on the truck (and the house, and with the baby) that I don't need or want to add maintenance. Heck, my truck has been in the carport waiting on a leak fix for at least a month now...

[mikec4193]

I am doing a 235 stock (out of a car) with a stock 4 speed and a 1985 K5 Blazer rear end in it with 4.10 gears in it...I should be driving sometime in the next couple of months...

Honestly with the massive weight of these things...I would be surprised if I can get it to go 55 mph.....my goal is 60 to 65 but I think that will be down hill with a tail wind...

Keep us in the loop...I am really curious to see how it works out for you...

MikeC

P.S. a flashback from the early 1980's we used to race 250 cu in 6 cylinder Camaros at the local oval track an with that size and weight vehicle....they were a freaking blast...sideways in the corners and everything...they ran so fast I saw more than one of us up on our top....even wrecked one so bad I had to take an ambulance ride...so in a car they used to be fine....that was a different era then...

[sawyerrm]

Thanks for the info. I think I'm leaning toward the crate 350/automatic types. I looked into some that were still stock but they don't seem practical for driving to work on the freeway. On the other had I don't want a hot rod which many of them are.

I'm paying someone to inspect this one today

https://losangeles.craigslist.org/ws...285454366.html

And maybe have this one inspected next week

http://phoenix.craigslist.org/cph/cto/5273602099.html

They're both a bit over my budget so I might need to have a bake sale to pay for them.

Based on the inspection reports and how much I can haggle with them, I'll fly to LA or Phoenix and drive and buy one of them. It's a slow journey but I'm enjoying the ride and everyone on the site is so helpful. I'll post the reports on a separate thread once I get them.

Rob

[62 Barnfind]

Originally Posted by sawyerrm

I'm looking at 55 - 57 Chevy trucks on EBAY and CL. They seem to be in two camps, those with original 6 cylinder and those that have a crate 350 etc. My hope is to drive the truck to work every Friday. This involves about 10 miles of SF freeway driving. Not looking for high performance but I need to safely enter the freeway and keep up with everyone ~ 65 mph.

The general question is driving a classic truck to work on Friday practical?

The specific question is do I need more power than a 6 cylinder provides.

Apologies in advance for the newbie question.

Rob

I have a 235 in my 62 that I just rebuilt. I had it bored 30 over, put an oversized cam and two barrel carbs on it. I am still running the manual 3 speed and 390 rear end. i can run 75 no problem except for the high rpm. I just acquired a 3 speed overdrive that I hadn't installed yet but I know it will run great when I get it in. The six can do what you want if you set it up right.

[TJ's Chevy]

If you already Have the 350 laying around I'd use it. But if you like being different then the 6 cylinder won't let you down. They put 235's in large trucks so it Does have the torque to pull freeway speeds. Nothing taller gearing or more gears can't fix. The all out best option would be to go with a 250. They are the cheapest to add performance mods on. My 292 would cruise at 3000 all day if I wanted it to. Especially when I added the 4 barrel and headers. The improvement made in power and on the torque band was surprising. A 292 with a 4 barrel, headers, HEI will get fair mileage and more power at the higher range. Adding a T5 behind it to lower your RPM's at freeway speed will just make things better. But if you wanted to go into the motor and make it a street engine the 250 would be the choice. Mainly because its more affordable. I hopped up my 292 for power. Will be making around 310 hp and 340 torque at the flywheel and is backed with a TKO600 5 speed. That with the 3.73 gearing and 31 inch tires(66 chevy c10) I'll have Plenty of umph and Freeway RPM's will be around 2500. Lotta options to choose from out there.

[Foot Stomper]

Here is a great little site that calculates everything for you. http://www.advanced-ev.com/Calculato...ze/?ratio=3.08

Plug in three of the four data fields and it easily figures the fourth for you.
RPM, Tire Diameter, Speed, Gear Ratio.

I learned that my 261 6 cyl turning over at 1997 RPM with my Coker Classics 31.1 inch Diameter with my gear set of 3.08 will coast along 60 MPH.
OR
at 2300 RPM 69.1 MPH

[MARTINSR]

Honestly, you are thinking about this too much. Get the original six and drive it and enjoy it.

Brian

[bmwlrj]

I agree with MARTINSR......I have original 235, four on the floor in my 59 3200 and it runs fine on the highway at about 55-60 no trouble...just take care of it....oil, plugs, etc....235 is a workhorse.

[nail pounder]

Will my stock 235, 3spd column, 3.90rear end have enough cajones to push 31" tires? Im running 28" now and 55 seems like it's spinning pretty fast. I've used the calculator, I think 31" would keep my rpms down and I could run 60mph easier. I don't want to burn up my new clutch trying to move it off the line either.

[TJ's Chevy]

Originally Posted by nail pounder

Will my stock 235, 3spd column, 3.90rear end have enough cajones to push 31" tires? Im running 28" now and 55 seems like it's spinning pretty fast. I've used the calculator, I think 31" would keep my rpms down and I could run 60mph easier. I don't want to burn up my new clutch trying to move it off the line either.

It will be fine. I went from 29 to 32 on my 64 GMC 305 V6 with 4.10's and hardly noticed a difference.....even in speed.

[Foot Stomper]

Although my truck isn't on the road quite yet I'd say your fine because I'm running 235 with 31" Coker and 3:07 diffy. I expect no problems at all.

[Rude Dude]

Last time I was in the Bay area during rush hour the top speed on the freeway was 30 to stop and go traffic. What a nightmare

[nail pounder]

Originally Posted by Foot Stomper

Although my truck isn't on the road quite yet I'd say your fine because I'm running 235 with 31" Coker and 3:07 diffy. I expect no problems at all.

Manual trans or auto? What size rims? Original?

[mikec4193]

Originally Posted by nail pounder

Will my stock 235, 3spd column, 3.90rear end have enough cajones to push 31" tires? Im running 28" now and 55 seems like it's spinning pretty fast. I've used the calculator, I think 31" would keep my rpms down and I could run 60mph easier. I don't want to burn up my new clutch trying to move it off the line either.

Hi Nail Pounder

Currently my 1953 truck...it has 4.10 gears...stock 4 speed...235 cu in motor...31" tall tires....it tops out at 52mph....foot flat on the floor...and yes it is screaming pretty good too...like yours...

To be honest....driving a stockish truck this old faster than 60 mph wont be a real enjoyable thing to do....they were never designed for this speed...they wander around a lot too...they dont steer all that good either....stock brakes are a concern too...

Keep it below 50 and enjoy the ride...

Good luck with your project...

MikeC

[nail pounder]

Originally Posted by mikec4193

Hi Nail Pounder

Currently my 1953 truck...it has 4.10 gears...stock 4 speed...235 cu in motor...31" tall tires....it tops out at 52mph....foot flat on the floor...and yes it is screaming pretty good too...like yours...

To be honest....driving a stockish truck this old faster than 60 mph wont be a real enjoyable thing to do....they were never designed for this speed...they wander around a lot too...they dont steer all that good either....stock brakes are a concern too...

Keep it below 50 and enjoy the ride...

Good luck with your project...

MikeC

Yeah, I hear ya Mike. I'll put some miles on it before I do anything. Stock is cool and fine around town but I'd like it to be a daily driver. I've been spoiled with my 66,SBC 350,5 speed, PS, PB, it has me purring down the freeway 70-80mph. I love that truck and body style but the 55-59 have always been my favorite. I've got disks up front & dual master cylinder, just did the clutch and motor mounts, it's just slow. It's a work in progress, I'm reading about the t5 trans swap, that's an option. I want to enjoy this truck as much as my 66.