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Discussion Starter · #1 ·
Ok guys, here we go.

I got a 55 Chevy 2dr sdn with a 350 small block and about 325 to 350hp. At this time it is running a 350 turbo trans with a B&M shift kit.

Would like to go to a overdrive in order to bring down the RPM's when on the highway. I have got 3:56 gears with a posi unit, and rear tires are about 26.5in. tall.

The motor will run around 2900 RPM at 65 MPH. I would like to be down to the 2200 to 2300 RPM at this speed.

So now iam looking into a 700R4 or overdrive unit. I have heard alot of bad things on the 700R and HP. They just don't seem to go togeather. On the other hand I have also seen ads and comments on aftermarket 700R's ( like Raptor, TCI, and Bowtie ) that seem to contradict the stories.

On the Gearvendors Overdrive I have heard nothing but good stuff, other than the price being a little high. ( about $2500.00 )

I use this car for cruise nights and shows, but also for vacations from NJ to NC and TN (we do cruise nights and shows their too)

Would be intersted in hearing pro's or con's on the 700R4 vs Gearvendors Overdrive.

Member - AMC/Rambler "guru"
1,851 Posts
Early 700R4s are a bit weak. You want one from 88 or later (I think that's the year), or an earlier one that has been rebuilt. Any 700R4 made before 88 that has never been rebuilt will cost a lot more to get rebuilt than a later one. The reason is all the upgrades to improve strength are added during the rebuild. Now if it's been rebuilt before it should be no problem, but the only way to find out is to tear it down. An honest shop would give you the not rebuilt price to start with then charge less once they found out some or all of the upgrades had been made, but who are you to know the difference? In most OD autos it's the OD gears that are a bit weak. When racing simply don't use OD.

How much HP do you have? If you have a modest SBC 350 you shouldn't have a problem with a late model 700R4 -- 400 hp or so, maybe as much as 500. Over that and you may run into some problems, but put the thing in "3" instead of "OD" when racing and it should be okay. Just don't be punching it in OD, just use it for cruising.

If you're concerned about power, go with the GV unit. It's tough enough!
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