3.07 gears 3 speed with a 292?

[davidh]

Instead of looking for an OD or finding the right T5 for my 67 C10 I thought of changing the rear to a 3.07. I have both a 3.73 and 3.07 5 lug. In the process of changing out front end.
I plan on using this as a truck but if its a real heavy load I'll just get my 3/4 ton. Might hall the occasional one axle trailer, bed full of parts, tree limbs etc. I'd like to be able to run 65 to 70 mph empty on the hwy. I have a freshened up 292, 3on the tree. Previously I had a low mileage 67 with a 250, 3speed and 3.73 with the 30X9.50's it wasnt bad with the little taller tire..
Anyone run this combo 6cyl and 3.07?

[Green Machine]

292 should have plenty of torque to pull the 3.07 gears. I'd do it !

[BCOWANWHEELS]

i,d hunt a sm465, 4 speed trany personally that way you still have a low enough 1st gear to pull a load on takeoff . where it will kill you is backing up and pulling out and if your on a incline it will kill your clutch. been a 3 on the tree man all my life and been there done that.

[Longhorn Man]

the 4 speeds came with a 3.07, so i don't see where this would be any different as far as clutch wear. Do it. If a 292 can't handle an empty truck witha freeway gear, then it needs pitched.

[special-K]

Sounds like a good plan.I just don`t like 3spds.As said,1st/reverse is so high you get chatter on hills and with loads when starting off.You can find a granny 4spd and slap it in easy and cheap at some point.

[BCOWANWHEELS]

4 speed tranys have a much lower first & reverse and i,ve never seen one come factory with a 3.08 gear

[Brad]

I realize this may be apple & oranges, but fwiw I put 3.07 behind a 250 in my old '67 and while it did great at cruising speeds and above, I had to use alot of clutch at stop signs to get it up and going.

[Shaky]

We put 3.07 gears in my buddy's '67 C10 with a 250 and 3/tree. Drove it to Alaska. No problem. Heavy load might be tough on the clutch though.

[54blackhornet]

I have a 68 GMC custom 1500, it was original with a 250 3 on tree.
GMC's have no spid so I can't tell what rearend I have, It now has a 292 30 over in it, you have to slip it pretty good to get it going but boy does it have torque. Any suggestions on how to determine what gear I have

[Shaky]

Originally Posted by 54blackhornet

I have a 68 GMC custom 1500, it was original with a 250 3 on tree.
GMC's have no spid so I can't tell what rearend I have, It now has a 292 30 over in it, you have to slip it pretty good to get it going but boy does it have torque. Any suggestions on how to determine what gear I have

Make a chalk mark on a rear tire. Hold the other if it is an open rear. Rotate the tire one revolution and count the number of times the drive shaft turns. If you're careful doing this you should be able to figure out the ratio.

If you pop the rear cover, look for the numbers on the outer diameter of the ring gear. Should say 40 13 or 41-11. Divide the big one by the little one. 40/13=3.07, 41/11=3.73, etc.

[68gmsee]

Originally Posted by 54blackhornet

I have a 68 GMC custom 1500, it was original with a 250 3 on tree.
GMC's have no spid so I can't tell what rearend I have, It now has a 292 30 over in it, you have to slip it pretty good to get it going but boy does it have torque. Any suggestions on how to determine what gear I have

My 68 is original with a 250 three speed on the column and has a 3.54 dana 44 rear axle.

[Longhorn Man]

pop the cover off and count the teeth. The oil os probably 20+ years old anyways and no longer doing the job it was designed to do.
And not all GMC trucks were SPID-less.

[Tx Firefighter]

In my 72, I used to run a tired 292, 3 speed and 3.08 gears. No complaint ever. Even my tired 292 never dissapointed me.

[vasquezmrysvll]

sorry to hijack.....but, i have a 67 shorty with rebuilt 250,hei,powerglide and 3.07 rear. im not planning on hauling loads,just cruisin. will this thing get out of its own way? i drove it on the property, never fast enough to get in to high. again sorry for the hijack.

[Brad]

Originally Posted by vasquezmrysvll

sorry to hijack.....but, i have a 67 shorty with rebuilt 250,hei,powerglide and 3.07 rear. im not planning on hauling loads,just cruisin. will this thing get out of its own way? i drove it on the property, never fast enough to get in to high. again sorry for the hijack.

It's got to be sluggish off the line, especially with that PG. Seems you've already figured that out.

[Shaky]

Originally Posted by vasquezmrysvll

sorry to hijack.....but, i have a 67 shorty with rebuilt 250,hei,powerglide and 3.07 rear. im not planning on hauling loads,just cruisin. will this thing get out of its own way? i drove it on the property, never fast enough to get in to high. again sorry for the hijack.

I've had a number of GM cars over the years that came with a PG and 250. The easy fix was always to swap in a TH350. No driveshaft change. Even the shift linkage would bolt up, but you wouldn't be able to get 1st.

The nice thing was you got a lower 1st gear with the same top gear. Made it a different vehicle.

[vasquezmrysvll]

i may do that. as for not getting first, the column is from a th350 truck. now i geuss i need to look for a radiator with a cooler. my glide is air cooled

[Shaky]

Originally Posted by vasquezmrysvll

i may do that. as for not getting first, the column is from a th350 truck. now i geuss i need to look for a radiator with a cooler. my glide is air cooled

Or just run a big stand alone cooler. Ditch the air-cooled 2-speed.