[Lenox273]

Have a 200 4r installed in my 70' Tempest but it is not ready to drive yet. Currently has a 3:23 open rear. Getting ready to order a new posi unit and better gears and was wondering what you guys are running and how you like your selection. Thinking of getting 3:90s. The Isky cam I have is reccomended to run at least 3:90 gears anyhow and the rear tires are going to be around 27-28 inches tall. Any input on your experiences appreciated.

[gtome]

I dont have my 200R in yet, but keep in mind the 200r has a lower first gear than a T-350/400.

[antique69lemans]

I had a 200-4r in a 67 camaro.It was a stock 350 and 3.42 gears. Originally it had 3.08s but they were a little too tall. What is critical is rpm in overdrive. If your motor will not comfortably pull the car at road speed,the overdrive is not going to be of much benefit. I plan on using 3.55 in the 69 lemans with a mild 455 and 200-4r. I would suggest keeping the gears in the 3.50-3.70 range and running a good converter. If it were my project,and the car will drive as is, run the current gear and tune the motor. Afterwards you can evaluate it's effective power band.

[Scarebird]

Originally Posted by antique69lemans

...If your motor will not comfortably pull the car at road speed,the overdrive is not going to be of much benefit. I plan on using 3.55 in the 69 lemans with a mild 455 and 200-4r...

Run 3.55's with my 200-4R, works better than the 3.23's on the freeway.

[Billz428]

I have 3.73 with a 27in tall tire, at 2200 rpm in OD locked up 65mph , everything just clicks right together.
Around town is perfect.
Trans is level 3 Bowtie Overdrives with their 2600 extreme series converter.
I run a deep pan,700r4 filter and a B&M Super cooler.
I,m very happy so far,but I have not raced it, just some burn outs and some hard running now and then.

[455wagon]

I have a 70 GTO and I put in a 3.73 with the 455, I also have a 86 OLDS full size wagon with 3.73 and a 403. Both are perfect with the 200R4. The wagon has 295/15/60 and the GTO has 275/15/60 rear tires, both about 26 inches tall.
Once and awhile I think the Wagon needs a 4:11 but that is only around town, once on the freeway all is good.

[roadrage david]

3.42 rear ratio. 25.79 tire hight. 1900/2000 rpm at 62/65mph.
If your engine is less powerful il go with a 3.73...........

[racegto65]

I am currently putting 3.90's in my street GTO with a 200R4.A 200R4 and 3.90:1 gears will give a final drive ratio of 2.61:1.

[lust4speed]

I have 3.36's in the '67 GTO cruiser and they are too high. I had them so I used them, but would definitely go with a 3.55 if starting from scratch. I've got a mild HR cam, but would choose 3.73's if my cam was larger.

[Steve C.]

TH200-4R / 3.73 gears with 27.76" diameter Nitto Drag Radials. Engine speed about 2300 rpm at steady state 70 mph. The converter is a 8-inch Continential non-lock up, about 3400 stall, with about a 200 rpm slip on the open road. Very streetable, car runs in the 10's at about 3750 lb race weight. Engine produces over 600 ft.lbs. torque from 4100 thru 5700 rpm and has no issues at a low cruise rpm.

[amcmike]

Here's a good article that talks about 1st gear ratio multiplication.

http://www.chevyhiperformance.com/te...ing/index.html

The Isky camshaft recommendation is probably based on a TH400 1st gear ratio (which is only 2.48). Your first gear multiplier in that case would be 9.672. With the 2004Rs 1st gear of 2.74, a 3.53 rear would give you the same multiplier. So anything between a 3.50s to 3.70s would be ideal, but you wouldn't need to go higher than that. Think of it this way, a 3.90 rear with the 2004R would be like trying to launch with 4.30s with a TH400!

As for your final cruise rpm, remember that when using a non-lockup torque convertor you need to consider a couple hundred rpm extra for slip.

[Lenox273]

Thanks everyone. I plan to call Isky this week to ask about the reccomendation. I was wondering myself if that was for 1:1 high gear driving or 1st gear. Car will be street driven 90% of the time. Highway driving in od will be about 30-40% of that. Looks like the 3:90 may be a little too high though.

[gtome]

I had a friend with 3:55 and a 220r, he thought that 3:73 would have ben better for highway cruising.

[69Farburd]

3.55's with 25 inch high tires behind my 428.

[lust4speed]

Also, I had a 4:11 12 bolt that was in the car when I swapped to the 2004R, and I first ran that combination. It felt good on the highway, and cruise RPM was still very reasonable. What was bad was the heat generated by running the low ratio at extended periods of 85 MPH - it bubbled the paint on the rear diff cover. It's good to remember that the rear is still running at the low ratio and does generate a lot of heat.

Steve C., how long and hard have you run the 2004R? My trans has everything I could put it in, and with the low stress behind my street engine, it should last a very long time. Just wondering what the life expectancy is behind a 10 sec engine?

[b-man]

You should always keep in mind the tire diameter you'll be running as this affects the engine RPM at all speeds, I see the originator of this thread will be running tires around 27 to 28 inches tall.

I plan to run a 3.36 gear with my 2004R, but my tire diameter will only be around 25.85" tall if I'm running 215/70-14s or even shorter at 25.3" if I swap to a set of 235/45-17s.

Cruise RPM will be very close to 2100 at 70 MPH for the 215/70-14s and around 2150 at 70 MPH for the 245/45-17s, perfect for today's highway traffic that rarely runs at or below that speed.

As long as I keep a mild cam in the '64 Tri-Power 389 I'll be running the engine should be happy cruising along doing only about 1500 to 1600 RPM at 50 MPH in overdrive.

[Steve C.]

"Steve C., how long and hard have you run the 2004R? My trans has everything I could put it in, and with the low stress behind my street engine, it should last a very long time. Just wondering what the life expectancy is behind a 10 sec engine?"

My TH200-4R was built by Century Automotive & Transmission out of Richmond, Texas. They called it a Stage III build for whatever that's worth, it has all the expensive bells & whistles that they use for the Buick GN turbo cars and high horsepower Vipers. They knew the torque potential of my car when we discussed the situation when it was built in '07. Except for the rare apperance on the drag strip, for the most part to confirm a 10-second time slip (10.63), my car is used only for the street now so I expect it should be ok. We did incounter a small hitch at first with slippage but that was corrected, while out for service it was then I changed from the origional lock-up converter to the non-lock up that is in it now. I did not like a lock-up converter and do not mind the 200 rpm slip out on the open road. This all said.... I do not baby it on the street. And if worried about the strength and if I wanted to race more often I have a custom exhaust system installed and the transmission can be dropped straight down without removing the exhaust. At the shop with the car on the lift and with a transmission jack the change can be done in about 20 minutes to remove the overdrive and put back in my built TH400 transmission & driveshaft.... then off to the races if desired.

http://www.popularhotrodding.com/fea..._am/index.html

[Overkillphil]

Cars 1, 2 & 3 = 200-4R/3.42 (26"), Car 4 (in avatar)= 200-4R/3:36 (27").

[Blue '66]

Originally Posted by lust4speed

I have 3.36's in the '67 GTO cruiser and they are too high. I had them so I used them, but would definitely go with a 3.55 if starting from scratch. I've got a mild HR cam, but would choose 3.73's if my cam was larger.

Are you using lock up converter with you 200r4?I also have 3:36 in my '66 GTO,I'm not planning to use a lock up converter.

[moontower69]

i have 3.55 w 70r4 on 65 gto stock 389 tripower, had 3.73 but a little revy around town, with 3.73 it especially held second gear a little too long for traffic driving and first gear was over in an instant w 3.73

3.55 is better all around for a mild car in my opinion