Ring and pinion gear ratio

cstew47

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Well, I also thought he went and got a new truck... even though I had seen previous posts about him getting the axle rebuilt. It wasn't until I got a few posts in that I put 2 and 2 together.

Mine is 4.10's, 35's, and a 350... it will do 65mph without too much issue, but is definitely not "cruising". It will eventually get a 4L80 to calm it down when the 454 goes in.
I went with the 4L60 because I didn't want to mess with electronic controls. This tranny should be good for my 400hp 383. Sounds like you're planning a torque monster. That 4L80 is nearly bulletproof.
 

82sbshortbed

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I'm having trouble following you. You said initially that you have a 3.73 then later you say 2.73? You don't say what engine you are running so I don't know what kind of torque you are generating. I assume you have a TH350 or possibly 400, so, if you are concerned over 2700rpms at 55mph, a reasonably torquey engine should be good with a 3.23 gear set. I have always run 700r4's so I can run a lower gear.


3.73 in replacing the old 2.73 gears. Th350 and 28" tires.
 

DoubleDingo

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3.73 in replacing the old 2.73 gears. Th350 and 28" tires.

I bet it hauled ass with 2.73s in there. May have been a dog off the line, but once moving no lack of mobility. Any idea which route you're going on this? Re-gear? Tire change? Both? Overdrive?
Yes he said 100 bucks fir set and 10 bucks for the crush sleeve for 3.08. That's why I was thinking cheaper than trans and rims and tires.

I'm gonna drive it some more with new better radiator and see how I like it. It sure gets better traction with that posi and shifts hard. I do like that about it. We'll see, that's why I like hearing different people with different gears give their experience with real time driving.

Looking again at your list of gear options, it definitely looks like 3.08 is the good gear to go with if no overdrive is being installed. 2,772 rpms at 75 mph. You could still drive 80 along with everyone else and get better mileage on the slower roads, which are rare over there...lol...

I still crack up every time we go to Texas, and end up on a beat-down two lane road with massive potholes, no shoulder, and maybe 6 inches of pavement beyond the edge line if there is one, and the posted speed limit is 70.
 

illmanners

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A chevy small block in good condition will run all day long at 2700 rpm without doing any damage. My concern on that issue would be gas mileage, not engine wear. (given that the engine is in good condition.) However, a ring/pinion change would be the least expensive way of lowering highway rpm, but you won't see a lot of RPM difference (at 55 MPH,) between 3:42 and 3:73 gear sets. If your goal is lower RPM at 55 MPH, 3:08's are the ticket, but you are going to lose some low end power. It's a compromise. Hope that helps.

illmanners
 

Bextreme04

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A chevy small block in good condition will run all day long at 2700 rpm without doing any damage. My concern on that issue would be gas mileage, not engine wear. (given that the engine is in good condition.) However, a ring/pinion change would be the least expensive way of lowering highway rpm, but you won't see a lot of RPM difference (at 55 MPH,) between 3:42 and 3:73 gear sets. If your goal is lower RPM at 55 MPH, 3:08's are the ticket, but you are going to lose some low end power. It's a compromise. Hope that helps.

illmanners

He has a 454... high RPM is a bit more of a concern
 

82sbshortbed

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A chevy small block in good condition will run all day long at 2700 rpm without doing any damage. My concern on that issue would be gas mileage, not engine wear. (given that the engine is in good condition.) However, a ring/pinion change would be the least expensive way of lowering highway rpm, but you won't see a lot of RPM difference (at 55 MPH,) between 3:42 and 3:73 gear sets. If your goal is lower RPM at 55 MPH, 3:08's are the ticket, but you are going to lose some low end power. It's a compromise. Hope that helps.

illmanners


I agree but have a bbc 454 in there and want to drop the rpms. If I change the ring and pinion I'll most likely go the 3.08 gears. The BB has enough low end torque to even spin the tires from stop with the 2.73 in there. Lol

And then before the swap I could run 60 at about 2200.
 

82sbshortbed

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I'm looking at a better radiator for it. I was gonna put a new one in anyway. Then move the temp gage outta the gage cluster because I can't see it very well in the old clocks place. When I drove it home I couldn't see the temp very well till I got home and it was about 220. Not overheating but, could be a problem if I keep getting it that hot all the time.

When I killed it jumped to over 235. That's what got me concerned about it.

Eventually I think I'll will put a 700r4 so I'll have od and I don't think the 3.73 will be bad then.
 

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