Does anybody have any ideas of what I should do with my problem of only being able to go about 60 MPH before my RPM's shoot up way high? My 65 originally came with a 6 cylinder, so maybe the rear end gears? Which ones should I go with?
Hello, You didn't mention if you still have the six cylinder or not, Or what transmission you have ,,,BUT... Your truck probably came with either a three speed column, a 4 speed ( with compound low ), or an automatic. The rear end ratio you have now, will depend on what trans came with it but the high RPM, ( and gas consumption) is a combination of trans and rear ratio. You will need to determine what you have now in the way of rear end ratio to figure out if changing things there is a good way to go. It will be a compromise of losing bottom end peppieness to get lower RPM's at the high end. I have the same problem that I am about to correct. I have a 4 speed and a 3 :70 rear. In January I'm ditching the manual trans for a 700 R4 and leaving the rear ratio as it is. I'm hoping to retain the low end performance and, by keeping the rear ratio the same, get it into the RPM reducing overdrive at 45 to 50 MPH. If you wish to keep the trans you have then the rear ratio is the place to investigate. Remember that you will lose low end torque by modifying the rear, so consider carefully what ratio would be best for your driving habits. Dennis
Yup I know the feeling. My 65' L/B has a new 350ci 320hp engine in it but I too have the original 3 on the tree tranny. At 55-65 she really whines. I have a 700R4 on my bench that needs to be rebuit and then I'm swaping out the 3-speed. And keep the rear for low end. The tranny swap is a major undertaking though. You of course have to have a cooler for the automatic and 12 volts to get the overdrive to lock up. Plus cut the drive shaft and move the cross member for the larger housing, yatta, yatta, yatta. Man, I may just put a manual 5-speed in it thinking about it. haha MC
Or host sells a beautiful book. How to restore your old chevy. In that book it covers a overdrive that came in trucks and cars ,both manual and electric. It takes some getting used too while driving. But i can promise you it is fun, different, and you can still be close to original. give it a shot
It seems that is the "classic" question with anyone working on these old pickups. I've been dealing with the same problem for years now, and haven't gotten around to fixing it. I have a Chevy 305 under the hood with a 350 turbo auto tranny. Originally, it had the 235 and 3 on the tree. It screams at 60. I've been told that the 700R4 is the best bet (as the other guys here mentioned) if you want to keep the low end power. Otherwise, you can swap out your rear end for a late model, or have the gears swapped. If you change the gears, you better go to someone that really knows what they're doing...otherwise, you'll be in a world of hurt. My suggestion, which is what I'm gonna do...if you got the $, go get a nice 700R4 tranny. The conversion isn't all that tough. Good luck. Regards, Arizona64
I went a different (and in my opinion - more desirable) route. I have a 1966 C10 shortbed stepside p/u. Originally had the typical 250/3 speed combination. 3.73 rear end. Ran pretty good at 60. Top cruising speed on the interstate was 65. Not good enough to safely cruise the SLOW lane in Atlanta traffic. I swapped the 250 for a 292 (with some hop up goodies - cam, headers, 4 bbl, etc.) and swapped the 3 speed for a GM A833 New process 4 speed. This is a transmission with 4th gear overdrive. GM used this tranny as an option in light duty full sized trucks from 1982-86. Has the very typical Chevy manual tranny bolt pattern and is a no mod fit for the old 3 speed - even uses the same yoke and clutch! You get a 3.09 first gear and .73 ratio overdrive. So now instead of turning about 3k rpms at 60, I turn 1900. I don't even go into 4th gear unless over 55 mph. 80 mph is only 2600 rpms - merely loafing! Only down side is the big drop from 3rd direct to 4th overdrive. It's a really wide ratio transmission. But the gears are almost exactly the same as the 700R4 (3.09 - 1.67 - 1.00 - 0.73). If you get the factory shifter it'll clear you bench seat too. Biggest mod is cutting a hole in the floor. A half day swap at most. ftyler
ftyler: I'm in the same situation you were in and your post helps me as I've been looking for a solution. I also have a '66 Step Side with three column only I have 230ci from a '66 Camino that someone put in it at some point. I'm in the planning stages for a full restoration and looking for a solution to upgrade driveability without too much modification from original. I thought I had the answer when I learned there was a 4 speed manual on the floor option for 1966 but turns out it was granny 4th which I don't want. I am not very knowledgeable about mechanics so I have afew questions for you if you have the time: 1) Why did you chose the 292 instead of 1966 option V8? 2) What do you mean by "only downside is big drop from 3rd direct to 4th overdrive"? 3) What do you mean by "If you get the factory shifter it'll clear you bench seat too"? Thanks for your post. Stephen
>>>I thought I had the answer when I learned there was a 4 speed manual on the floor option for 1966 but turns out it was granny 4th which I don't want.<<< You certainly don't want that boat anchor - at least not to fix the problem of low top end. The transmission I have is an all aluminum case box that resembles the BW-T10 and Muncie - just a little larger. It has a 10 bolt side cover and if you opened the case you'll notice that the 3rd gear is smaller than 4th. That's because the shifter lever for 3rd and 4th is inverted so that you "activate" what is normally 4th direct when you shift into third and you "activate" what is normally 3rd when you shift into overdrive. >>>I am not very knowledgeable about mechanics so I have afew questions for you if you have the time: <<< I'm not very knowledgeable either, to be honest with you. Looks like "dvalentine" is the resident expert. But I may be able to help out. >>>1) Why did you chose the 292 instead of 1966 option V8?<<< Strictly personal preference. I like being different. And because of the planned usage of my truck - cruising the interstates & state highways and occasional hauling to the landfill - I had no reason performancewise to go with a v8. You rarely see people keep an inline 6 in their vehicles these days. So it's really a surprise when I pop my hood and people see the straight six (with a 4 barrel & headers & crazy chrome). The 2 inch duals and Flowmaster Muffler gives the straight six a deep, throaty v8 sound. And for acceleration and low end torque the 292 can hold it's own against some smaller displacement v8s. And with the 11 inch clutch it's REALLY easy and effortless to spin the tires even on dry pavement. >>>2) What do you mean by "only downside is big drop from 3rd direct to 4th overdrive"? <<< I simply mean that the RPM drop is fairly significant when shifting from 3rd gear to 4th. As a result my acceleration is not very strong in overdrive. But then again overdrive is really for cruising, not acceleration. And because I usually don't go to overdrive until I'm at 50 mph (or above) I already have enough torque left to easily take me to 70-75 mph on the interstate. >>>3) What do you mean by "If you get the factory shifter it'll clear you bench seat too"? <<< This transmission was designed for work truck use. Therefore the shifter was made to clear a bench seat. I have a spare one of these that didn't come with a shifter. Once I put it to use I'll have to find a 4 speed bench seat shifter to clear a TRUCK bench. Have you priced a bench seat truck 4-speed shifter? NOT CHEAP! -ftyler
Hey Ftyler. Do you have the casting numbers off of that trans. I have a 56 and the shifter portion might be what I'm looking for. Ed
I have a spare one of these transmissions in my garage so I'll get the ID numbers of it. Should be able to lead you to the shifter. -ftyler
ftyler, would you want another 292 for parts? I have a basket case that had a piston pin walk out & score the block. The builder also dropped something on one of the rod journals of the crank & scratched it a bit, but it could be polished & the block can be sleeved. New water pump & fuel pump, only a few hours since a rebuild. Came out of a '67 C20 & I used it about three hours until the problem occurred. If interested, please e-mail me at: bud45@bellsouth.net I also have a complete 250 with an internally cracked block- blows coolant out the exhaust- otherwise ran well, other than the problem. The 292 ran also (drove it to the shop for an engine swap) before teardown/diagnosis. Bud
as I am no expert on chevys I have been around awhile so here goes depending on the trans you have. if it is a three speed with the 6 banger it more than likely has a 3.73 ratio depending on which tire you have will have a lot to do with your rpm. my 66 has the 3.73 ratio and i am running 275/60/15s on the rear my tach says about 2400 at 65 mph. most of the automatics had a 3.07 ratio, and the granny 4 speeds had 4.11 or 4.56 ratio. so to answer your question an overdrive transmision will keep your low end and let you cruise also. chief
