TC,

My 1970 SS just got a professionaly built 200-R4 installed with a 3200 stall converter from Century Transmission (http://www.centurytransmission.com/cart/). I have to report this was the single biggest improvment I have made so far. Completely different car now. 3.42 gears meant 2800-3000 RPM on the highway at 65. With the new tranny, it's 1900 RPM at 70. :hurray:

The lower trans gearing has woken up the car as well. It's sporting a 496 BBC, solid roller, ported 781s, and a ProSystems carb. The shop removed the restrictors in the secondaries and the carb performance stepped up significantly. Took it for a drive today. Wow!

So, if you can do this type of mod, it is worth the money and effort. It really takes advantage of the torque of the 496.

Just had to share. :D
E.

That's amazing. Enjoy it....:disco:

:thumbsup: I enjoyed the TH350 to 2004R change also.

Quick update with a bit more info. The acceleration with the new transmission is much better and takes good advantage of the torque of the 496. With the 3200 stall, RPM is kept higher up in the band where there is probably 500 lb ft of torque available. If I stand on it from a stop, it smoke the hides, shifts and then starts smoking them again. When the tires hook up around 50 or so, it just launches the car. :beers:

On the lighter side, I took a 60 mile cruise on the weekend, all highway, and except for one little jump to embarrass a Honda SC2000, I've picked up an additional 2.5 miles/gallon on mileage. Folks laugh when I say this, but I get 12.5 mpg now. Up from 10 mpg. 20% improvement. :thumbsup:

Anyway, positive results all around.

The only negative I have is that with the higher stall, the engine has to be at a higher RPM to leave the line. Once I get used to that, it won't matter.

Cheers,
E

Your motor sounds pretty high-strung, how does it like those low RPMs on the freeway? My 468 didn't really like the .64 OD and 3.73 gears. I switched to 4.11, and now it's 2000rpm at 60mph. That 200 RPM raise made for a much happier motor. Well, my old build I should say, I sold it last night and will be installing a new ZZ502. I think they are a little less high-strung. By the way, with my old gearing, driving 60mph on the freeway, no messing around, no stop/start, I got 21mpg once with the OD. I don't care if anyone thinks I am stupid, I know how to divide miles driven by gallons added to replenish the tank.

Your motor sounds pretty high-strung, how does it like those low RPMs on the freeway? My 468 didn't really like the .64 OD and 3.73 gears. I switched to 4.11, and now it's 2000rpm at 60mph. That 200 RPM raise made for a much happier motor. Well, my old build I should say, I sold it last night and will be installing a new ZZ502. I think they are a little less high-strung. By the way, with my old gearing, driving 60mph on the freeway, no messing around, no stop/start, I got 21mpg once with the OD. I don't care if anyone thinks I am stupid, I know how to divide miles driven by gallons added to replenish the tank.

Those are some good numbers. I can squeeze about 18mpg out of mine, but I have to keep it lean and drive like granny 90% of the time.

Just leaning out the idle circuit makes a BIG difference in cruise mpg.

Your motor sounds pretty high-strung, how does it like those low RPMs on the freeway? My 468 didn't really like the .64 OD and 3.73 gears. I switched to 4.11, and now it's 2000rpm at 60mph. That 200 RPM raise made for a much happier motor. Well, my old build I should say, I sold it last night and will be installing a new ZZ502. I think they are a little less high-strung. By the way, with my old gearing, driving 60mph on the freeway, no messing around, no stop/start, I got 21mpg once with the OD. I don't care if anyone thinks I am stupid, I know how to divide miles driven by gallons added to replenish the tank.

No issue with the low RPM. I built the engine for torque not HP at high RPM. I intend to keep it under 6k RPM. I kept my 781 heads and had them fully ported and polished. The solid roller cam has a good profile and a 112 LSA so I get good vacuum for the brakes. When the tranny goes into 4th, the converter locks up immediately. There is a big drop in RPM, but the car starts accelerating faster with the same throttle input. I attribute that to the converter locking up and providing all the torque to the wheels. I have 3.42 gear and 26" tall tires

I think the mileage will be higher, I was expecting around 15. It should do better on a longer run. I am going to install a vacuum gauge and make a road trip to see how it goes driving with the gauge.

Thanks,
E