Bowtie Overdrive 2004R

[Bob Chadwick]

I got a sweet deal today. I was over at The Last Detail and was talking to this guy about his 74. Seems he had put a BTO High Performance Street level two transmission into his car and didn't like the way it had matched up to his rear end gearing (I think he said it had a 3:55 in it). He ended up pulling it and replacing it with a 700R4, which is evidently better matched to the lower gears.

I bought it from him for $200. He had it in the car for less than a year and put less than 500 miles on it. I figure I couldn't rebuild mine for twice that and I can always drag it to Carlisle or elsewhere and sell it for more than I paid for it. It should match my 3:08's very well.

Now I just need to get Kenny to come over and help me put it in.

 

[LT4man]

Bob

You are really rolling!

TTYTT, I feel the 2004R is a stronger trans than the 700R4. I know I will be flamed on this, but I don't care! There are a lot of hot rodders and draggers that are using the 200.

Good for you. Your trans is gonna give you lots of fun for a very long time!

Save The Wave!

 

[Bob Chadwick]

Every body has their favorite and from what I have read, both can be built to similiar specs. The difference is the gearing. The 2004R likes the highway rear end due to it's lower first gear. The 700R4 is supposed to be a better match to the taller rear end gears.

I had a link to a post explaining all of this but it's dead.

 

[Ludigdrums]

I put a 700R4 from a '93 Firebird in my '81 and I love it. I have the stock 2.87 rear gears.

I must say though, that I could probably use a taller (numerically higher right?) rear gear. At 45MPH I'm only doing around 1000 RPM which makes the engine bog. So around town I try and keep it in 3rd to prevent the overdrive from kicking in.

Otherwise I love the acceleration in all gears compared to the turbo 350 that was in there before. And the overdrive is great, however, I really don't think it's helped my mileage much, and I thought it should have. Maybe because of the rear gear, although I can't see how going to a taller gear would help mileage cause the engine would be turning faster?

- Jeremy

 

[Scooter76]

Great deal:

I'll give you $300 for it!

 

[Bob Chadwick]

I put a 700R4 from a '93 Firebird in my '81 and I love it. I have the stock 2.87 rear gears.

I must say though, that I could probably use a taller (numerically higher right?) rear gear. At 45MPH I'm only doing around 1000 RPM which makes the engine bog. So around town I try and keep it in 3rd to prevent the overdrive from kicking in.

Otherwise I love the acceleration in all gears compared to the turbo 350 that was in there before. And the overdrive is great, however, I really don't think it's helped my mileage much, and I thought it should have. Maybe because of the rear gear, although I can't see how going to a taller gear would help mileage cause the engine would be turning faster?

- Jeremy

Jeremy,

The 2004R is supposed to match better with the lower gears on both ends where the 700R4 is supposed to match the larger gears better.

Bob

 

[Bob Chadwick]

Great deal:

I'll give you $300 for it!

:L Great try. I suspect I could take it to Carlisle this August and get north of $500 for it.

 

[Rowdy1]

HMmmmm...

:L Great try. I suspect I could take it to Carlisle this August and get north of $500 for it.

You "might" have a problem getting that on the plane as a carry on.

 

[Bob Chadwick]

You "might" have a problem getting that on the plane as a carry on.

Who's flying this year? I plan to talk the week off and make a leisurely drive north.

 

[Jack]

Super deal Bob!!

I got a pretty good one this week too ... a 377" race motor (destroked sbc 400) ... fresh +30 400 block, world sportsman 2 heads, manley sportsmaster popup pistons, 6" manley sportsmaster I beam rods, steel GM 350 crank, new gold race crane rockers, eb torker2 intake (4sale $45), kevco claimer pan, moroso deepvee billet pulleys ... I pulled it down before buying ... miked EVERYTHING AOK ... bankruptcy prompted sale price ... $750.

 

[Bob Chadwick]

Super deal Bob!!

I got a pretty good one this week too ... a 377" race motor (destroked sbc 400) ... fresh +30 400 block, world sportsman 2 heads, manley sportsmaster popup pistons, 6" manley sportsmaster I beam rods, steel GM 350 crank, new gold race crane rockers, eb torker2 intake (4sale $45), kevco claimer pan, moroso deepvee billet pulleys ... I pulled it down before buying ... miked EVERYTHING AOK ... bankruptcy prompted sale price ... $750.

I'll say. Doesn't it make you feel good. Almost makes up for all those other bad decisons.

 

[craig32]

ok, I'm a little confused on 'taller' gears. Taller meaning higher ratio? 2.87 is about as high as they go, right? 4.10 and 4.56 are lower, correct? Hence 1st gear in a standard gearbox being like 4:1, while 4th gear is 1:1. From what I've seen elsewhere, 700 autos were designed for trucks, where 200's were for passenger cars. I understand the 2004R can be rebuilt much better than they were from the factory, probably why the 700's were so popular with the Vettes. Either way, the 'R4's are supposed to be better for mileage, where a TH350 has no overdrive. I haven't moved up to the OD scene yet, as I have 3 vehicles with the TH350, and the Vette gets about 12-13 MPG - I fully understand the want to swap them!

Craig

 

[Bob Chadwick]

Now I'm confusing myself. The 700 is supposed to be better for cars with gearing toward the 4 end of the spectrum. The 200 is supposed to be better for the gears near the 3 end of things.

 

[craig32]

Now I'm confusing myself. The 700 is supposed to be better for cars with gearing toward the 4 end of the spectrum. The 200 is supposed to be better for the gears near the 3 end of things.

OK, that sounds right, a truck would have lower differential gears, while a passenger car would have the higher (2.87, 3.08) gears. Apparently you are reffering to a lower gear ratio set as 'taller' gears, and not higher meaning taller. And if guys are putting lower rear gears in their Vettes, that would be why they prefer the 700 over the 200. I understand now, just never heard gears refered to as taller, especially to mean lower.

Craig

 

[Bob Chadwick]

I equated the gears to that on the wheel of a bike. The bigger gear is the power gear, like the 4:11, and the smaller gear is the speed gear, loke the 3:08.

Perhaps an incorrect analogy? In any event, we are now on the same page as to differentials.

 

[Ludigdrums]

Ok, so I think I got it now. Shorter gears are numerically higher (like 4.11), and taller gears are numerically lower (like 2.87). So, the way to remember it is that it is backwards of what you would think it should be!

Now that we have that straightened out...I feel that I have heard the opposite regarding who prefers the 200 or 700.

The 700 first gear ratio is 3.06 verses the 200's 2.74. So, when you combine the 3.06 with a short rearend like 4.11, your first gear is very quick (you only get to 35 MPH in first), as opposed to with the 200's 2.74 you'd make it to about 40 MPH.

So, it seems to me that if you have a very tall rear (2.87), then you'd want the shorter first gear of the 700R4 because it would get up and go faster than the 200R4. However, if you have a very short rear (4.11), than you'd probably prefer the first gear of the 200R4 because it wouldn't be as quick and you probably wouldn't spin your tires as much as if you had the 700R4.

Does this make any sense? Am I correct in my thinking? I remember when I was researching the threads on this topic, that this is the info I recieved.

Also, I found this awesome excel spreadsheet called GearRatioCalculations, and it allows you to enter in your transmission type, rear gearing, and tire size. It then calculates the RPMs in each gear at a given (you enter it in) speed, as well as shift RPM, top speed in gear, total combined gear ratio, etc.

I forget where I found it, but if you want it, email me and I'll send it along!

- Jeremy

 

[lightingrod]

This should clear it up!
http://www.bowtieoverdrives.com/catalog/catalog.php?Action=GETSUBCAT&CATID=WA4

I have a BowTie stage III 700R4 (rated at 630hp/630tq) sitting in my garage, bought it before I got the engine done! All my friends talked be out of using it with the 496, so I sure as heck not going to use it with the 572! My little Cobra has a 700R4 with a 3000 rpm stall converter by Bulldog Transmissions out of Florida. I think I need to check the TV cable because I don't like the way it shifts. It's not firm at all! Been thinking about putting the BowTie in my 454SS, my tranny guy just laughs? Wonder what he means by that?

Al

 

[Bob Chadwick]

I've got to call them next week. Their web site has a couple of crucial broken links.

 

[Rowdy1]

Tall, Small, High, Low..........

The higher the # as in 4:10, 4:56 REAR, the faster you will accellerate depending on the transmission ratio, BUT the less top end or comfortable cruising RPM you will have UNLESS you have an overdrive transmission dropping your highway gear to below 1:1 ratio. If you have higher #'s in the trans as well as higher #'s in the rear as in 2.64 to 1 in first, as opposed to 2:87 to one in first, the 2:87 will wind up and redline you quicker.:confused

 

[Bob Chadwick]

INstallation Instructions From Bowtie Overdrives

BTO was kind enough to email me the installation instructions and confirmed that the swap from the TH350 to the 2004R should not require any driveline modifications and will retain the same yoke.

Looks simple enough.

They also sent me a complete conversion parts list for the remaining items possibly involved. I may or may not need all of them. Be aware that if you are making this conversion that the transmission parts may only be half the cost, or significanly less if you got a deal on the tranny.

Torque Converter: 2200 Heavy Duty 1$175.00
Crossmember: 68-79 Corvette Standard rubber mounts1$195.00
Shifter: 77-81 Corvette SC2403 1$90.00
Inspection Cover: 2004R Univ. plastic 1$25.00
Dipstick: 2004R 1$30.00
TV System: Quadrajet [1902/1903/1904/1905/1906] Throttle Bracket Duel Non Braided1$119.95
TCC Wiring: TCC Brake Switch Kit 1$28.00
Transmission Lines: 2004R Side Tank, 1$129.00
Speedometer Gears: New Set 2004R Drive/Driven Gears Drive Gear: Driven Gear: 1$46.60
Installation ToolsCost
Install Kit(Pressure Gauge Blk Temp Gauge Inline Filter)$67.00
Misc ItemsCost

Sub Total$905.55
Tax$0.00
S&H$81.36
Total$986.91

I also noted a Torque Converter Clutch Lock up Wiring Kit for another $70 on their web site that is not listed here and I am looking into whether or not that is needed.