I`m running 3:50 gears in my `29 roadster. 283/TH350 and it buzzes around 2500rpm @ 60 mph. Not much for gas mileage. In comparison the `35 Slantback has a 3:00 ge****t with a 355/700R4 and cruises at 1600 rpm @ 65 mph getting almost 22 mpg but it has a lot of rpm drop between shifts so it seems lethargic stoplight to stoplight. With todays gas costs I`m leaving it alone.
I am not going to get into the whole high low thing with anyone. It is a dumb arguement to have and can't be won by either party. now as far as your gears, a 2.75 gear is an airplane gear, it will put your cruising range up so high that you will own every county courthouse in a 4 state area. Unless you are going to bash the salt you don't need legs that long. I would shoot for a gear in the 3.0:1 range. I like a 3.26 gear for a tradeoff and it is an off the shelf ford gear, pretty easy to find.
Okay, so here comes the stoopud part...... I'm ready, beat me up, Can an auto trans (C4) "lug" an engine? or does it just "kick down" a lot when you need acceleration?
It shouldn't kick down at speed unless you mash the go peddle to the floor. It depends on how everything is adjusted. The deal on gears is that you want your engine to be close ot if not right at the bottom of the torque band when you are cruising. You small block is not going to like pulling a load @ 1800 rpm so you want to be cruising where it wants to start pulling a load. Remember that at highway speeds you are oulling more of a load than at say 25 MPH, you are not driving a ****er knife you are driving a brick and it is going to be pushing a lot of air.
I am with traditions racing on this one . Always was and always will be a 4:11 is a low gear rearend and a 3:08 is a high gear rearend. Higher the no. lower the gear ratio. Its like putting a 327 in inplace of a 6 banger and still running the stock 6 cylinder rearend. The higher no.rearend holds the engine back on topend. Tell a professional racer to put a low no. reargear in his dragster and he'll look at you like you are a TV racer that knows nothing about cars at all.
Which first gear ratio is your C4? Keep in mind, you will see a 300 rpm difference for every gear jump. Thats a rough rule. Meaning.... If you run 2000 rpm at 273, then you will be 2300 with 308s. I personaly think your gonna be close, perhaps right where you want it. If you havent picked up a TQ converter, that may be the deciding factor as well.
****** puts it well. 3.08 was long winded but not bad for a light weight A model, esp w/a torque converter in line. Even from a 2.73 you'll notice an improvement.
I had a 3.50 in my coupe with a 700r4. I was very happy with it. I also had a complete pumpkin with 2.70 gears. For the summer, I'd throw in the 2.70, because it was great on the open road. The 9" pumpkin is so easy to change it wasn't a big deal.
HA! the "douche bag" comment wasn't meant to be a parallel to you. I had an actual person in mind in my friend group who always does it...
I tend to add the word "numerically" to my comments of gear ratios being high or low, because when I leave it out, a side discussion of what is and what is not frequently and somewhat justifiably breaks out. http://www.508pir.org/events/images/2009/normandy/2009_sme_odonnell_34.jpg "It depends on what the meaning of the word 'is' is. If the--if he--if 'is' means is and never has been, that is not--that is one thing. If it means there is none, that was a completely true statement..." - William Jefferson Blythe III Clinton
I agree with your ****ogy and am feeling that 3.00 or 3.25 may be better to keep the engine in the sweet spot. Very well put. It is an easy change. For about 2 hundred for another R and P, if the 2.75 doesn't work, it's an easy fix. What I've gathered from all this is that the 2.75 is in worth a try and if it falls on it face, I'll do a switch. Thanks guys!
I had 3:00's in my '32 3 window and it worked out as a good compromise, however, there were times I wished I had higher gears, Like cruising with the "Early Times". Those guys don't cruise, they race! My '49 Ford had 3:55's which would lay rubber all through first gear, but she rev'd high on the freeway. I switched to 2:76's and cruising at 75 was no sweat. I did lose acceleration with the 302/C4 combo, but I prefer long distance cruising anyway. Not to mention, better mileage.
There is no absolute answer to the question. That transmission, as are the majority, is a compromise. It doesn't have the range of ratios needed to give you everything. At one extreme you can gear for max acceleration. At the other extreme you can gear for max economy, which would have the engine just below peak torque while at cruising speed. Everything in between is a compromise. What's right for you may or may not be the same trade-offs that suit the next guy. So, view the responses in the context of what you want your car to be.
In my mind burning rubber off the line is about traction of the rear tires compared to the force needed to actually move the car forward. If your car is heavy and/or has gears around 2.70, the tires would often rather spin than move the car forward...
That is just the opposite of what most people I know refer to. A higher gear is a lower number, just like in a transmission. First you need to determine where the "sweet spot" is on your torque curve. Too tall of gear might lug the engine and be detrimental to mileage and power. On a stock V8, I shoot for around 2200 rpm at cruise. I'm running a 3.70 gear with 29-30" inch tall tires and a T5 so that gets me right into the range. Some guys with a little bigger engine seem to like theirs at 1800 and get good mileage there but with a 260, I still have some snort in top gear.
My '31 hiboy has a 302 HO, C4, 2.8 gear. 2380#. Problem is the torque converter with its 2800/3400 stall speed. The "flash stall" is 26/2700. I never reach stall even at 60mph were I'm at 2150 rpm actual. This means that the converter is making torque and not turning the trans pump and building lots of heat. If I drive in 2nd gear (1.5x2.8=4.2 final ratio) I get stall at 2900rpm. (rpm = mphx4.2x336/29) (29 is the tire dia) Not a good road combo. I'm going to a 3.55 and a 2000 stall. I don't race but I like to punch it now and then. I am probably over cammed also but that is yet to be determined, we'll see how the new gear and torque converter works out.
the high low thing is funny. if one way or another were common knowledge there would be no need for the term "numerically lower/higher"
No, in this case (as in most) it's because someone doesn't understand a definition. "Gear ratio" is a speed ratio of input to output. That is the definition. At a given input speed (RPM), a 3.4 gear ratio will give a higher output speed than a 4.1 gear ratio. That is why a 3.4 gear ratio is a higher gear ratio than a 4.1 That is why a lower Numerical ratio is a higher gear ratio.
Who the hell cares! We all know what the other is talking about! The only thing that should matter here is that the O.P. gets the advice that is needed and not whether it's tomato or tomaatoe! I'm getting the freakin' popcorn, this thread became stupid.
I had a bologna sandwich with pickles and then a peanut ****er sandwich. I always get those little popcorn dealies under my plate.
Ok, this will solve the debate. Let's just do what the old timers did and call them "desert gears" or "mountain gears". No question there what is higher or lower.............and it's TRADITIONAL ! Don
Only you know what "decent pull" means to you. One guys "decent pull" is another guys "goddam stone".
No the difference is that some of us actually know and donot have to go on line and find a dictionary. That and we have learned to pic our battles and know that there is no reason to joust with windmills.
As a friend of mine from Detroit would say, "well ya know", I had a 1978 TA with 2.20 gears from the factory. It ran surprising well on both ends. Of course it had the 403 Olds engine and with a speedo that only went to a hundred (if I remember correctly) I rarely knew how fast I was really going. Many cars in the 60s and 70s had gears in the 2.80 range. I believe you'll be surprised at how well you setup will work in a light car.
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