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Discussion Starter #1
So I currently have a 727 in my car, 3500# AMC 436 inch rambler engine N/A. Runs 10.50s at 127 and should be faster as engine should be pushing 700-750hp. Anyway the trans is a stock unit with an extra friction and a b&m shift kit, still fully auto. Converter was built for me by a friend about 25yrs ago and was checked last yr but I think that is where the issue is.

Problem is I am at the limit of trust with the 727 as it needs a drum and sprag and a trans brake installed and with cost of converter(amc specific) I think going to a 400 would be smarter and the converter can be any gm one so I can experiment easier.

I have three 400s, one is a 475 straight cut from a motorhome and other is normal one, 3rd is an AMC specific one. Is there any benefit from the straight cut gear one or just use the normal one and stick an ultra bell on it. The AMC one is twisted to clear the front drive shaft on a jeep so would rather not use it.

What Brake do you recommend, and what other modifications should it get. Thanks.
 

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Ah, I missed the fact you will need the Ultrabell to adapt to the AMC motor. A 4L80E doesn't seem to lose much if any ET to the equivalent TH400. We went from a 400 to a 4L80E in car running 6.70s in the 1/8th and it actually went slightly faster. Converters were identically spec'd from the same vendor but I suspect the 4L80E converter was a bit better.
 

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Discussion Starter #6
Besides the trans brake, what else is needed for the 7-800hp range? I assume the sprag in the motorhome unit is 34 element. Does it need drums etc like the 727?
 

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Discussion Starter #8
So now after thinking it over I may just stay with my tf, order a new converter and put a brake in it, new bolt in sprag and drum
 

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So now after thinking it over I may just stay with my tf, order a new converter and put a brake in it, new bolt in sprag and drum
To each their own, but I wanted to switch from a 727 to a 400 a year ago and got out voted by my dad and transmission builder, and have had nothing but issues with the 727 since, and missed a few races this year, and it looks like we're spending the money twice to go 400.

If we had it to do over again, we'd take the 727 case to the scrap yard with the beer cans.

Besides safety, the ultrabell has some other advantages that make it worth the price, such as packaging size (it's smaller in some areas), and it's much easier to get to the bolts when servicing.
 
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