Best Gear Ratio
- Thread starter trhccd
- Start date
When you encounter the vibration/pulsing at 2000 rpm, what happens if you change gears and hold the same speed? If the problem disappears it could be an exhaust harmonic. Chased that problem in a '35 Ford coupe many years ago, after drive shaft balancing, tire truing, and various engine tunes. An H pipe solved it on the coupe. That probably won't be a solution for a T-Bucket but it might ease your mind to know it's nothing more serious.
SRM1952
Member
Is the vibration the same in 2nd gear at 2000 rpm at this time the driveshaft speed is less than in high gear . If it is a driveshaft , rear axle or tire speed the vibration will differ .
Just an other test to try.
I do not know why this occurs in the 2000 rpm range, but I bought a new 99 Mustang SVT Cobra that had the vib at 2000 also. Ford flew a NHV tech down with a device that was zip tied to the rear axle, gear housing. By the frequency of the vib he could tell which item in the drive line was causing how much vib at what rpm. I tried to advise the op of how to address this in an earlier post. Apparently it was not deemed applicable. Good luck with the other methods.
roadmonster
Member
I have a 350/350 with 3:00 gears and I love it. 275/60s out back, around 2000@60mph. This combo with a somewhat tight converter (~2100 stall) gives great street performance and comfortable highway cruising. I have a Comp 252H which is made for tall gears and has 800-4800 powerband, as does the Weiand Action Plus manifold. So you're basically ALWAYS in the powerband and shifts occur at maximum torque. It will fly away from other cars at traffic lights without making much of a fuss about it. It will also lay plenty of smoke and chirp 2nd gear if you want.
Face it, much of your cruising is poking around at 1800 rpm, and you might as well have some torque and power in that range. I would not trade my 3:00 for anything.
Dezolde
Member
By comparison, my bucket build underway has 383 SBC w/ 700R4 and 31" tires. Am hoping to be about 1900 @ 70 mph. Does that sound about right?
Thanks,
Jerry
choppedtop
Well-Known Member
I have 700r4 with 3.55 gears, 31" tires and run 2100 rpm at 71mph.
Lee
Lee
roadmonster
Member
700R4 runs lower rpms. Just look it up on the chart. There is also a DML(?) tire calculator which has a great tire size chart. Google it.
Hot Rod Todd
Member
I ran a 540 cube blown BBC with 4.56 gears in the rear, with 31.5 tall tyres. I dreamed of getting up to 4mpg like Ron did with his blown bucket 
I was well under 3mpg, but a pair of 1250 dominators really werent good street carbs either.
Seriously tho, with a 3 speed non o/d box and 30-33 tall tyres 3.0 gears will be okay on the open road provided your engine has some decent torque. Or go to about 3.8 gears if you have a 700R4 or similar box.
With 3.0 gears in my bucket, and a pair of 750 Edelbrocks, I got to 11mpg on your US 3.8 sized gallon (our gallon is 4.5 litres)
I was well under 3mpg, but a pair of 1250 dominators really werent good street carbs either.Seriously tho, with a 3 speed non o/d box and 30-33 tall tyres 3.0 gears will be okay on the open road provided your engine has some decent torque. Or go to about 3.8 gears if you have a 700R4 or similar box.
With 3.0 gears in my bucket, and a pair of 750 Edelbrocks, I got to 11mpg on your US 3.8 sized gallon (our gallon is 4.5 litres)
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