I love reading the posts of you racers. I on the other hand, have a 100% street car. Granted, it has a lot of "race" parts, not the least of which is a 540" HEMI. My question is: have any of you ever installed TOO MUCH converter? I asked the advise of a 727 guru that I still respect, and allowed him to choose the converter for my 4,175lb. convertible street 66 coronet. It has the aforementioned HEMI, producing over 600 ft.lb. of torque, with a 3.54 gear. I was always disappointed in the "rubber band" acceleration. The tack never moved, as the speedometer caught up. I really never paid attention, when I installed it, but upon removing it, I find that I have a 8" converter that is much more appropriate for a light car with a high rpm engine with a 4:56 gear! I am replacing it with an 11" "tight" converter. Any experience with "TOO MUCH" converter? I would just "blow through" that little converter every time I tried to launch the car. If so, what improvements did you see in et and MPH?

Whos 8" converter and what stall was it advertised at from your 727 guru? I hope you didn't do this blindly. I figure you had to have some input in this.

So now, your installing a 11" "tight" converter, who specked that for you and whats its advertised stall. Also whos vert did you go with this time?


Your looking for improvement "estimates guestimates" between the two verts with out providing enough info about the two verts IMO

Also, at what rpm were considering you were at "blow through"

Sounds like you went from 1 extreme to the other when there are many options in between.

Hmmmmm...........8" converter in a 4000lb street car with a 540" HEMI. Likely would not have been my first choice

Monte

Since I used A&A Parts, I let Rick recommend the converter. It was a Transmission Specialties and was supposed to be a 9-1/2" with 3500 stall. Actual stall on the street with 275 Triple R Nittos was 4000 rpm. It just never felt like it "hooked up". I could stab the throttle at any RPM and it would "flash".
I put up with the soggy throttle (even at freeway speeds) until I purchased a Gear Vendor unit from a member here. Knowing that this would make the problem even worse, and having to pull the trans anyway, I decided to change the converter at the same time. Gear Vendor suggested I call Hughes as they said they worked with them a lot on converters for overdrives. I talked with Hughes who recommended an 11" 3000 stall. I called TCI, PTC, Turbo Action, and a couple more. Everyone of them wanted to use a 9-1/2". I had been there, done that. I then talked to racers, some very fast street cars some with Blowers etc. The consensus was, "you don't need a lot of stall with over 600ft. lb. of torque at 4000 rpm. So I went back to the converter companies and talked to all of them AGAIN! Hughes was the only one who could offer an 11". We compromised on 2800 target stall with special stator etc.

In all of the research and conversations with racers, I heard that an 8 inch could have an efficiency as low as 70%. Some said that an 8" would never "hook up" in a powerful car. That is why I posted this on this forum. I wondered if racers had experience with too much converter? If so, what happened when you tightened it up? How efficiency did you pick up? How much does "size matter"?

There are so many variables that it is impossible to give a decent answer to this one. No converter expert here, but It sounds like the driveability "feel" is as important to you as all out performance, which it should be with a street strip car. You may be more satisfied with a matched smaller duration cam/tighter converter combo. How much duration do you now have, and where does to torque start to come in?
with 540 cubes, a STOCK stall range 426 Hemi converter is a good fit if built strong enough to handle the torque. It will probably stall minimum 3400 rpm. They won't live without some improvements though,AMHIK. Mine lasted six passes behind a 535, 3600+ stall out of that stock factory 10 3/4 converter.