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Discussion Starter · #1 ·
Hello all,

So have a 74 nova, 3250 pounds, sbc 406, 5.13 gear. Glide, 1.80 first. Engine peak torq 5500, peak power, 7000.

Current converter where it ran its best et flashes to 5800-6000, i have a second converter, flashes to 6000-6200. Car is about .08 slower with the looser converter. Big thing i noticed with the looser converter, to hit the tree the same off the footbrake, i had to raise my launch rpm almost 800 to nearly 4000 rpm. The other converter, is pushing hard at 3200.

So to say the looser converter was alot less agressive. It was suggested to me that this was because the tighter converter was closer to peak torque.

It was also suggested to me that something may not be right with the looser converter.

So debating whether to try a tighter converter, maybe in the 5500 range,

Or have another looser converter built. I have read that you want about 500-600 fall back on the shift, so i would need a converter in 6500-6600 range.

Looking for advice from a technical perspective, and not try this builder or that builder.

On another note, imo, car has always 60 footed its azz off, bit mph was slow for et.

Thanks in advance.
 

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Here is my experience and opinion, It is worth every penny that you are paying for it. :rolleyes: On a low powered combo, in order to make a converter looser, the stator becomes less efficient. You can't have your cake and eat it too. On a bracket .5 tree deal, I would probably go with the looser and give up the ET. The car will repeat better. If on a .4 tree, i would use the more aggressive one every time. My 2 cents, maybe one of the experts will chime in. Your combo makes pretty decent steam, so there may easily be a sweet spot in between, you just have to find it.
 

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I’m just a back yard wrench. But from my experience and research, for my 3700# 1.80 glide 1040fhp set up. Peak torque is at 6100 and I shift at 7k ish. Mine drops to 6100 at the shift. Converter is an off the shelf TCI pro x 9”. Specs state 6200 NA stall and 6600 with power adder. Seems to work ok, runs 9.50’s in 7500 air.
 

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I would say tighten up the converter. If your converter is 6100 and you are shifting at 6900 the converter will drop back to the stall speed at the shift. It will be more consistent if it is not laying on the converter at the shift for too long. My car the converter is tight. stall on the launch is 6000. shift is 8000. RPM after the shift is 6100. I have a 1.96 low and 6.17 in the rear. The car is very consistent. 336 cu in @ 3150. went 10.14 last weekend in less than stellar air
 

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Discussion Starter · #12 ·
Hard to believe that a few hundred rpm would kill it almost a tenth. Both Opel cores or is one an 8" saturn?


Hutch

I am not sure which core they use, but from the outside, they both look identical. Any way to tell from the outside?

I just seems that other converter is just lazy. I agree, something just doesnt seem to be right. I may send it back to them to have them check for anything wrong, if nothing found, may just tighten it to 5600.
 

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Discussion Starter · #17 ·
Witness marks from flexplate bolts concerns me
It was barely touching, the converter had fresh paint on it, and basically just rub the paint off. I do shim thr converters now, without the shims, it was on the high side of the acceptable range of pull out, so i added .060 if my memory serves me correctly.
 
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