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Old 09-28-2019, 03:31 PM
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Wink Big block motor, 350 trans, Needs stall...

Hello all,

It looks like my transmission is on its last leg here and taking its sweet time shifting into a higher gear+only at high RPMs. A rebuild is mandatory, but I've gotten a decent run from it after it was recycled from my old 327 SBC. I figured, while I had the tranny out for rebuild i'd like to put the appropriate stall converter in it. Something mild, car should be street-able with the occasional track pass. It's a 454 BBC bored .60 over a with 10.5:1 compression and a nasty cam. The fellow said it was a .527 lift, but I have my doubts. May have been blowing smoke up my arse to try and seal the deal In any case, it sounds lumpy and mean. Motor isn't lazy like some of those big blocks. I'd wager with the bolt ons (qjet, highrise, longtubes) it's putting out about 470 ponies, no less, to the wheel(s). I should say wheel, singular, as I still haven't got around to putting in a posi. One step at a time, or one wheel at a time though so which stall would be good for me?

I've been posting a good bit recently and trying to get more active on the forums, I'll upload some pictures of what i'm working/w soon. Thx 4 help

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Old 09-28-2019, 09:10 PM
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Without knowing cam duration, or the RPM point the engine really starts to come on the cam, along with rear gear ratio and what you expect for performance or street/strip behavior it will be impossible to recommend a converter stall point.

Unless your rebuild guy really knows his stuff, and what hard parts will need tp be replaced inside the trans, don't expect a TH-350 to live long behind a 450+HP Big block. Just the required drum and sprag will set you back $300+, and that doesn't include any of the other regular rebuild parts.

Switching to a TH-400 now would be the smart choice, rather than rebuilding the weaker TH-350.
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Old 09-29-2019, 08:11 AM
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I second the info on the th350. I'd never run one behind a big block, EVER.....A th400 is a much better choice...

As to the converter, I won't buy an off the shelf converter for anything anymore. Custom all the way. For your application, it won't cost much more if any more than a shelf converter and you'll get one that's set up specifically for your combo....much better money spent if you ask me.
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Old 09-29-2019, 10:52 AM
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I'm with the growing crowd, a TH350/700R4/4L60/4L60E are just plain in over their design limit. It's torque more than horespower that tears up transmissions and the BBC delivers plenty of torque in any configuration.

I wouldn't consider anything short of a TH400 or 4L80E for behind your engine unless this is strickly a money racer and the trans is just a consumable in pursuit of wins. In that case the lower power tax of a TH350 might be justified, but on the street with some reliability and life span needed there is no way.

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Old 10-01-2019, 02:32 PM
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If your transmission has a factory stall torque converter, I'd have my doubts the cam is real wild. You'd be idling high enough to where the converter is fighting the brakes while stopped. Plus, it'd feel doggy taking off. If you have power brakes, do they work all the time in any condition, or does the pedal get hard when stuck in traffic? If they do, cam ain't very big.

Th400 will live longer in stock form, but a th350 can be made to take a beating, just how deep is your wallet is the big thing.

I'll recommend a custom converter too, I bought one and am darn happy with it.

One wheel peel can make an engine seem stouter too, "it'll fry the tires forever" is something I've heard plenty before, and the engine be a plain old 350 with the cam, intake, carb, and headers treatment.
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Old 10-01-2019, 11:21 PM
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I bought the engine from a fellow after I blew my 327 and I just mated it up to my old transmission. Chevys are good like that. Car DOES has a disc brake conversion. Everyone keeps telling me I should get a 2500 stall for street app, they all have a little mechanical knowledge and have seen the car but the forums here offer information unparalleled to what I hear.
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Old 10-02-2019, 06:55 AM
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Sounds like the vacuum to the shift modulator is weak or none existent. If tranny fluid is still the same color as when new the tranny is ok. When did you last service it?
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