Hey guys, hope this topic hasn't already been beaten to death, I did a search but i couldnt find what i was looking for.
I'v been thinking about putting in some 4.10/4.11 gears in my car, i currently have 3.73's with my 700r4 tranny and 26' tires and it cruises great. i don't do alot of highway driving so not looking for high end speeds or anything but im wondering if anyone else is running higher gears with thr r4 and how it is on street? how are cruising speeds (60mph or so) Id like to change them but i dont want to be so high in rpm when cruising. Any feedback?

 

I never found them necessary with the 700R4. The steep 1st gear in that (truck-based) trans doesn't seem to need much rear gear to get out of the hole, usually well beyond the limits of traction in most applications. I say stay put for now. When you've finally had enough of that weak little 305 and step up to a 350 you'll be wishing for LESS gear, in all likelyhood.

I had a 92 RS with a mild 350 that I ran with the 700R4 and the stock peg-leg 2.73 rear for a while. It was just stupid getting it out of the hole, even on DRs, with one wheel spinning, as you can imagine. I dropped in a set of 4.10s along with a posi (I had them laying around as a set so I used them). The gears were too much. It then spun BOTH wheels as bad as it used to spin ONE with the peg-leg rear. I went from running 13.5 to running 13.3 with little increase in MPH. First gear was just stupid-steep. It was gone almost as fast as I could bump the shifter.

If I had it to do over again, I would have done the posi but with a mellower rear gear that I could just "plant" off the line and made full use of the limited traction that the stock-sized DRs were capable of delivering through the near-stock suspension.

 

yea that was a concern for sure, with my set up know with DR i can plant it out of the line and as you can see in this pic, she launches for an ol 305.
I was also thinking that with my cam maybe higher gears would compliment it, maybe a converter change? Only problem i have with my cam is i think it has too much duration for my small cubes, 232/236 @.50..

 

Unless you're putting 90% of the emphasis on strip performance, I'd say your 3.73 gears are ideal for the motor and tire size you're running.
IMO, any car with a halfway decent torquey V8 is downright annoying cruising on the highway with anything more than 3.73's on a 26" or smaller tire.

 

yea, as far as cruising, it does really good as is, wasnt sure how big of a change gears would do to that.

 

Not to bad for a 305 with stock heads.

 

4.10 would be good with a different transmission like a TH350 etc but not for the 700R4. The low first gear of the 700R4 makes it a perfect street transmission. The deep first gear means you don't need a deep gear in the diff to get you off the line quicker. Add in the OD and poor diff gears get better fuel economy.

From a performance standpoint, the 700R4 isn't that great. The ratio between first and second means the rpms drop down out of the powerband during a WOT shift.

Your current combination of 3.73, 700R4 and 26" tall tires is about the best you can get. The powerband of the engine probably isn't much higher than 5500 rpm so high reving with deeper gears isn't going to help.

 

Just a FYI.There is a company who's name I don't remember,that fixed the 1/2 shift ratios on 700r's.

 

We tried one of those gearsets in my buddy's low 10-sec NA Impala. No gain whatsoever in his setup: 385 SR, 4.88 gearing, 30.5" tires, 4200 converter.
With milder gearing and TC, you may see a difference, but I wouldn't even consider throwing that much money for at most a gain of a few hundredths.

 

Yea i was considering putting in a th350 cuss I know the r4 isnt the best, as soon as i started making any power it started having a 1-2 rpm flare, luckily the corvette servo fixed that issue. The only thing that is holding me back for the th350 is the fact that it is a 3 speed. Wasnt sure on drivability at that point.
Not to mention the r4 takes around 55 hp vs the th350 which is about 30hp. So also looking at free 20-25 hp between trannys.

 

The internet "stories" just continue to get even better! Don't believe that 25 hp difference for one second! Except for some high-dollar TH350 race builds compared to a factory 700R4, you'll never see that.
The bottom line is: Anything leaning more towards street than race will be quicker with the 700R4. The only way I'd swap to a TH350 is to gain that last tenth in class racing where the swap was permitted. And a good racing TH350 is not cheap.
One thing going for the TH350 is that nearly any backyard hack can put one together. The 700R can be built to hold over 500 hp, but those that can do it are few and far between.

 

I ran 4.10s in my 9" with a 700r4 for years(lots of highway). It wasn't to bad, (my car is very modded) but i'd never do it with a stock 7.5 housing/gearset because of so many pinion failures, even on street tires..