[Les_Paul]

Hey all,

I'm going to purchase a 73 step side Chevy C30 with a 4 bolt main 350 small block engine this winter. It's in more than good enough condition to be a daily driver, but I might want to make it faster. I don't remember the exact transmission off the top of my head but it has a granny gear. Would switching transmissions alone make the truck faster? What else (other than standard exhaust and air intake methods) would potentially make the truck faster? I'll attach a photo of my soon to be vehicle! By the way, it has 50k original miles...no rebuilding nothing. Just plain awesome!

 

[327NUT]

I had an '88 Chevy 1 ton 4x4 with the "granny" 4 spd. and 4.10 gears = 3000 rpm @ 60 mph....hated that trans!!!! I ended up having a built 700R4 installed and it was absolutely a different truck. It wasn't any faster really just so much more enjoyable to drive. If you want faster then you'll have to get into the engine.......but if I were you I would do the trans first.

 

[spinn]

My c10 has 305/th350c and 3.73 gears and 28" tires. Drives 2800 rpm at 65mph in lock up. To me that is busy, but okay. 15-16 mpg cruise control on.

Gears and good heads do make a noticeable performance difference from behind the wheel.

One of the biggest improvements you can make is to the launch. A stock converter is not satisfing. A dynamic 3000 stall is, but will not work well with a 2.76 rear gear. A 3000 stall will probably accelerate around 4x faster from the hole with no loss in driveability. Not enough rear gear or engine, and it will feel slushy which is bad. My 305 only has a performer cam, that is small but sufficent for what I do with it.

That is not a trans dipstick in the picture. Undertand better now after a closer look. Disreguard stuff.

 

[Les_Paul]

Wow. I really don't know anything...I'm just getting started in the true mechanical aspect of vehicles. I have an understanding of maintenance and such but not more advanced things. Having said that, what is a stock converter?

And to 327NUT, what is a 700R4?

Thanks for the help!

 

[spinn]

Start reading up. A 700r4 is a overdrive version of the th350 auto transmission. A stock converter is the turbine sandwhiched between the engine and transmission. It multiplies your torque at a certain rpm for break away. Most drag racers will tell a race is won at the starting line. Launch is directly related to this. You can tune the driveline to the engines power band. Any mild build will benefit from a 2400 stall. It is the perfect compliment to a small cam/intake/header package. Don't stop short with your mods pull that trans back and launch hard.

A manual trans has the advantage of slipping the clutch with your foot. However you do not get the Fluid turbine torque multiplication at stall speed.

Good luck.

 

[OneMoreTime]

Having over the years several rucks with the granny gear I have never used the granny gear unless I had a need to go very slow like out in the field loading hay or something..I always stated out in second for my daily driving. Try that before getting into changing things..

Sam

 

[Silver Surfer]

Granny gear on a Chevy Truck. Then this is a manual and you do not have a torque converter. At least I have never heard of a granny gear auto trans.

What is the shift pattern? "H" with reverse down and right? You probably have a Muncie SM465. The low gear on this trans is NOT synchronized, so don't worry if it grinds when you try to shift into Granny mode.

Gear Ratios are:
First Gear - 6.55:1
Second Gear - 3.58:1
Third Gear - 1.70:1
Fourth Gear - 1.00:1
Reverse - 6.09:1

You can google pics of this trans and compare. It has PTO's on both sides of the trans case and covers that are held on with 6 bolts. There is another similar Borg Warner trans (T-19 I think, but I don't think that was ever used on Chevy trucks).

 

[Les_Paul]

Start reading up. A 700r4 is a overdrive version of the th350 auto transmission. A stock converter is the turbine sandwhiched between the engine and transmission. It multiplies your torque at a certain rpm for break away. Most drag racers will tell a race is won at the starting line. Launch is directly related to this. You can tune the driveline to the engines power band. Any mild build will benefit from a 2400 stall. It is the perfect compliment to a small cam/intake/header package. Don't stop short with your mods pull that trans back and launch hard.

A manual trans has the advantage of slipping the clutch with your foot. However you do not get the Fluid turbine torque multiplication at stall speed.

Good luck.

Thanks! Where would be a good place to "start reading up"?

Having over the years several rucks with the granny gear I have never used the granny gear unless I had a need to go very slow like out in the field loading hay or something..I always stated out in second for my daily driving. Try that before getting into changing things..

I have heard that also...I'll be sure to try that next time.

Granny gear on a Chevy Truck. Then this is a manual and you do not have a torque converter. At least I have never heard of a granny gear auto trans.

What is the shift pattern? "H" with reverse down and right? You probably have a Muncie SM465. The low gear on this trans is NOT synchronized, so don't worry if it grinds when you try to shift into Granny mode.

Gear Ratios are:
First Gear - 6.55:1
Second Gear - 3.58:1
Third Gear - 1.70:1
Fourth Gear - 1.00:1
Reverse - 6.09:1

You can google pics of this trans and compare. It has PTO's on both sides of the trans case and covers that are held on with 6 bolts. There is another similar Borg Warner trans (T-19 I think, but I don't think that was ever used on Chevy trucks).

I can't remember the exact model but I do know it is a Muncie transmission. What does it mean to be synchronized? Thanks!

 

[spinn]

Read here. The wiki and crankshaftCoalition have a wealth of knowledge. Become familiar with the parts of the engine and driveline. How distributors work, why they become a tooth off, or how the curve relates to engine power. Sometimes TDC compression and exhaust stroke are mistaken for another, How to recognize the condition. There is a lot of tradition with brands and carb tuning. Communities and forums can help clear the cloud, ask good specific questions. You can get your vehicle performing like you want and not spend a fortune. Although some still spend a fortune.

In post 3 I took a closer look at the 3rd picture, and it was not a auto trans in the picture.

Contributors like F bird88, double vision, ap72 , cobalt327, latech, cool rock daddy, 327nut, etc, play harder than me and tell it straight.

 

[Silver Surfer]

I can't remember the exact model but I do know it is a Muncie transmission. What does it mean to be synchronized? Thanks!

The SM in the SM465 means "SynchroMesh"...which is kind of a lie seeing as how granny gear isn't synchronized. Basically there are little spring loaded brass keys that engage inside the transmission, before the actual gears mesh together. This allows the gear shafts (which are spinning at different speeds) "catch up" with each other (synchronize) so that when you push the shifter all the way, the gears do not grind. A manual transmission rebuild kit will contain the parts needed to rebuild the synchros.

Before synchronized transmissions drivers had to double clutch. Clutch in, move gear selector to Neutral, clutch out (to allow gear shafts to synch), clutch in, move gear selector to next gear, clutch out.

The SM465 is a beefy transmission. It was used on 3/4 and 1 ton trucks. Heavy duty and hard to break (I think it weighs 185lbs too!). What is the rear axle in the truck? 14 bolt? It is certainly not a performance/race tranny.

Not sure your budget, or what you mean by making the truck faster. But a Borg Warner Super T-10 or New Process A883 transmission would be good. The ST10 is a 4 speed and 4th is 1:1. The A883 is also a 4 speed, but it is also over drive (!) and is significantly cheaper than just about all other quality transmissions you will find (but not as sporty as the ST10). The old Muncie transmissions (rock crushers) are good too, but definitely more priciest.

I have an 81 C10 with a ST10 and 3.73:1 rear end with Posi-track. It is like driving a go-kart! Much fun! But not fun on the highway, have to cruise around 2.5-3K RPMs and that like like 55-60mph (hence my A883 suggestion for over drive). I also have a lifted 84 C10 with an SM465, and it is a clunky loose trans with a long throw to shift gears.

Read here too for a similar question: http://www.hotrodders.com/forum/want-4-speed-219472.html

 

[Silver Surfer]

See here for actual pictures to match...

http://www.motivegear.com/tech_info/tranny_guide/tranny_guide.html
http://www.mackstrans.com/transID.html

 

[75gmck25]

There are at least 4-5 comprehensive sites dedicated to the 73-87 trucks, and you can get a lot of good info on the body restoration and model-specific info. The hotrodders forum is good for drivetrain info, and many of the other parts of the truck are identical to other GM products (e.g., steering column, brakes, axles, etc.).

73-87 trucks are all the same body design, but models were updated as the years went by. For example, HEI replaced points in '75, power locks and windows started in the late 70's, the overdrive 700R4 started in '82 and TBI fuel injection started in '87. In many cases you can install the newer feature on your '73, but sometimes it can get complicated. You can also use many parts from 88-91 Suburbans and 1 ton pickup trucks, since GM kept the old body style longer on those vehicles.

Most parts for these trucks are also relatively cheap, since they were widely mass produced for GM and for third party suppliers.

Bruce

 

[Les_Paul]

There are at least 4-5 comprehensive sites dedicated to the 73-87 trucks, and you can get a lot of good info on the body restoration and model-specific info. The hotrodders forum is good for drivetrain info, and many of the other parts of the truck are identical to other GM products (e.g., steering column, brakes, axles, etc.).

73-87 trucks are all the same body design, but models were updated as the years went by. For example, HEI replaced points in '75, power locks and windows started in the late 70's, the overdrive 700R4 started in '82 and TBI fuel injection started in '87. In many cases you can install the newer feature on your '73, but sometimes it can get complicated. You can also use many parts from 88-91 Suburbans and 1 ton pickup trucks, since GM kept the old body style longer on those vehicles.

Most parts for these trucks are also relatively cheap, since they were widely mass produced for GM and for third party suppliers.

Bruce

Thanks for the advice. The person I'm buying it from restores vehicles so I'm sure he'll be able to help me out too. The amount of knowledge everyone has here is baffling.