Slant 727 WIW
I couldn't get a Gear Vendor O/D with the 904,so I went with the 727 on my /6 !!!
Dennis,
If it's not for a race car, you'll never see the difference.
My problem with the Gear Vendors unit is the overdrive ratio. It's not really an overdrive in the same sense as the 4th gear in the 500/518 transmissions is because while they reduce rpms 30 percent on the overdrive shift, the gear vendors unit has just a 22-percent reduction. The reason for that difference in ratios, I am told, is that the G/V unit is built and sold mainly as a gear splitter band-aid device to assist towing rigs that need a gear between 2nd and 3rd, when climbing hills with big loads. Second gear is too low and third is too high... but a 22-percent overdriven 2nd gear is just right... splits the difference between 2nd and 3rd perfectly, giving ratios of 1.45:1, 1.28 and 1:1...
But, when used as an "overdrive", it only turns a 3.55:1 gear into a 2.76:, or a 3.91 into a 3.04, neither of which will give you relaxed freeway cruising like you'd get with a 518's .70 overdrive (3.55 X .70 = 2.49:1.)
But, your engine, with its long-duration cam, may actually LIKE a 2.76... we'll see.
Let us know how it works out. A 2.76:1 gear (a 3.55:1 with a 22-percent overdrive) should give you about 2,300 rpm at 60 mph (2,900@ 75 mph.) That is with a 25"-tall tire.
Those figures include a minimal amount for converter slippage.
BTW, I certainly don't blame you AT ALL for not wanting to go through the ordeal of installing a 500 or 518; I wouldn't want to cut up the floorpan in my Valiant for that!
