At least there was no sales tax saving about $100. They offered me a $250 credit on my old 278mm Circle-D single disk... maybe they do the same for the FTI single?

How do you know you're getting the 1A or 1B converter? Just ordered the 258mm triple disk in the 3400 to 3600 stall range. No where on my receipt does it say 1A-1B. Maybe the lower stall range 3400 is the 1A and the higher 3600 is the 1B lol

 

Loose as in you will have to rev the engine higher to get moving normally. My truck weighs 6k lbs on the dot and during a normal takeoff from a stop light, the engine revs to around 2400 rpm with the Cirlce D 265mm 1a. It was much lower with the stock convertor, like 1800 or 2k (don't remember exactly). Yes if you want a snails pace takeoff you won't need to go to 2400. If I didn't street drive my truck a lot, I would absolutely go higher stall (looser) for killer 4x4 takeoffs, but the higher revving for normal take off's really puts the mpg's in the crapper.

It really depends on what you are willing to live with. While I'm sure I could have better high throttle takeoffs with the 1b, normal driving is better with the 1a. The 1a for my heavy Crewcab 1500HD was looser than I was expecting. I believe it's just a stator change from 1a to 1b, so you could always send the convertor back to be reworked if you don't like the one you pick. So I went on the conservative side getting the 1a thinking I could send back for the 1b and stuck with the 1a.

 

Thanks, Red, for that info about turning in the old converter - I'll ask them about that whenever I scrape the cash together to order. Hopefully they'll take it.

Much appreciated, pknowles! I had it right, I just couldn't explain it. I remember discussing this with someone 30 years ago, but most of that info was all long since forgotten. That '78 Cutlass I had back then with a Crane 292H cam barely idled, yet had the stock converter! I used to get smoked by Ford Escorts at green lights for the first 100' because of that. It was embarrassing, lol. Didn't know how converters worked then. Once the tach hit 3k, HANG ON! She took off like a missile!

Red, I think that 1A / 1B thing could be a completely different build for our applications. I tow between 5,500 - 9k lbs. regularly with mine, so that could be why they suggested this custom build with a different part number. I think our clutches are probably the same, but everything else is different from there due to what we're doing with our trucks. My stall is going to be in the 2k- 2,200 RPM range not just for towing, but also because 4 months out of the year I have to drive in snow and ice. Flashing to peak torque doesn't work in snow, lol. You just spin endlessly and go nowhere.

 

That is a lot of stall for a blower , in my opinion. But it is all really personal preference.

 

Just an update ...

I talked with someone at Circle D about the "1A" vs "1B" subject. They stated that on the 265mm converters, the 1B is TIGHTER than the 1A.

On the 258mm converter, it is OPPOSITE. In that case, the 1A is TIGHTER than the 1B.

Hope this clears things up.

 

With the LS having such weak bottom end torque, I think with the blower it'll be just right. As it is in stock form, the truck hardly gets out of its own way until over 3k RPM, and really comes on nicely at 4k. Crazy high compared to what I grew up with.