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Torque converter for mild stroker

rmchrgr

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My friend and I are getting close to buttoning up his 438" stroker. This is a relatively mild build up. We have a 727 ready to go but need a converter. The input shaft has been updated to 24 spline to be able to install a '67-up converter which has a wider variety to choose from.

General specs of the motor below:

4.310" bore 383 with a 3.75" stroke crank = 438"
228/232 @ .050 hydraulic flat tappet cam, about .525" lift
440 source rotating assembly 383.438.5050 approx 10.0:1 CR
OOTB 440 source heads, 80CC, Comp Magnum roller rockers
Edelbrock Performer RPM intake
Holley 4160 3310 vacuum secondary carb
TTi headers with full dual exhaust
Electronic distributor, electronic ignition

This is going in a '66 Fury with 3.23 gears. Column shift, stock valve body, Lokar kickdown cable. Obviously a comparatively heavy car to get out of the hole that will see almost all city/highway driving. We made it a point to not overcam it because there is no intent to race it but he does want the car to 'jump' when he mats the gas from a light or from a roll.

Thinking a factory type 11" converter could be OK but the reason I'm asking for suggetions is because I have a feeling he could actually benefit from something with a little more stall, say like 2,500 rpm. I think the motor will make plenty of torque but we don't want to make it a dog if the converter is too loose, even at that low of an rpm. I don't imagine he'll be north of 4,500 rpm very often.

So maybe something like a TCI Breakaway or Hughes Street Master seem like a good fit for this application? We're not married to any one particular choice. I know it's always best to get a custom converter made for your particular application but this is a strict budget build and if we can predict decent enough results with an off-the-shelf choice that's what we're going to do.

Thanks for any input.

- Greg
 
Did the 438 stroker in a Barracuda. Same trans and gears that you have. Has a Boss Hog 2800-3200 stall. It has an Edelbrock top end kit tri-y headers with 3 inch exhaust. Car ran strong with a carb but has a Holley sniper with the hyperspark distributor, cd box and coil on it now and runs way better.
 
How is the 2,800 + stall? Our subject car is heavy.

No Sniper. I wish but not for this build. I'm literally giving him a ton of stuff off my shelf.
 
Not bad at all. Drives fairly normal but you can stall it up and it comes alive. You notice it more if you're pulling up a hill from a stop. The guy at ACC Torque converters took all we had as far as car and engine specs and built us one. Works great.
 
Contact a couple of the better known performance builders that have been mentioned many times on this board. Give them all your specifications and see what they recommend for your application. Just because the 10" Whiz Bang converter I have in my car works perfect for me doesn't mean it will work worth a damn in your vehicle. A good converter designed and made for your application is money well spent.
 
An 11" factory converter is going to see more than 2500 at the hit behind that engine, figure closer 3000 with the 3.23's and a 4000lb car.
 
Thanks cruisin.

I'm not a complete dope, I know I can "ask an expert" to recommend a converter. If this was my money to spend, I would be buying a custom spec'd unit and this thread would not exist.

But again, my friend is on a very tight budget. For him, every extra expense becomes a setback to completing the project. Whether it's the best scenario or not, for him, the most efficient solution is to find a basic, off-the-shelf unit. At his performance level, he does not need to get involved with the added expense of a custom converter, whatever that extra cost may be. I don't believe a less-than-perfectly-matched converter will make or break this combination to such a degree that he would even know the difference.

Anyone else have any input or suggestions?
 
If that's the case I would just bolt up a stock 11". Only thing that I would like to add is 7/16 bolt pads.
 
Funny you mention the bolts. Another friend of mine actually called the other day in the middle of installing his trans asking about flexplate bolt holes. He said he couldn't get the converter bolts threaded since the flexplate holes were too small and wanted to know if he had the right parts.

Honestly, I had no clue what he was talking about. I went an looked at a stock converter I had on my shelf which had a bag of larger converter bolts sitting right on top of the unit which made me think they came out of it so it didn't click right then. Dug out the flexplate and yep, small holes. I reached under the converter and the bolts were in the lugs, 5/16". I'll be damned. Did some quick internet research to confirm. Seems like only the Hemi cars and probably the 440-6 cars had the larger 7/16" bolts, everything else got the small ones. Haven't taken out 1,000s of 727s in my day to know that. Learn something new every day but that little fact is now burned into my brain.

Long story short, the guy who called me from under his car had to take the trans back out and enlarge the flexplate holes to 7/16". Right then I went and looked at the two flexplates I had on hand and both use the small bolts. Called my friend with the 438" and told him he was most likely going to have to buy a flexplate and/or make sure that whichever converter he decides on he needs to know which size bolts it uses.

Another expense for him!
 
Beware there are also two flexplate sizes. One for the big blocks and one for the small blocks. I think Performance convertors typically have the smaller pattern. Lots of aftermarket flex plates often have both patterns.
Hughes 2500 is a decent quality and price. I wouldn't get a tci, bosshog or b&m. You might be surprised what Ptc might be able to do custom and still be affordable.
I wouldn't probably go past 2500 w 3.23 as a driver on a heavy car w a 15 inch tire unless it was built for the car.
 
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Beware there are also two flexplate sizes. One for the big blocks and one for the small blocks. I think Performance convertors typically have the smaller pattern. Lots of aftermarket flex plates often have both patterns.
Hughes 2500 is a decent quality and price. I wouldn't get a tci, bosshog or b&m. You might be surprised what Ptc might be able to do custom and still be affordable.
I wouldn't probably go past 2500 w 3.23 as a driver on a heavy car w a 15 inch tire unless it was built for the car.
x1000 on PTC. That's what I run in mine and have been soooo happy with it. Keep it 11" and tell them all about the car and you want it to stall between 2400-2600. They'll nail it, the price is great and those guys seem like they wrote the book on customer service. Fast turnaround as well!
 
x1000 on PTC. That's what I run in mine and have been soooo happy with it. Keep it 11" and tell them all about the car and you want it to stall between 2400-2600. They'll nail it, the price is great and those guys seem like they wrote the book on customer service. Fast turnaround as well!

Well, not if you are outside the USA. I ordered one for my Coronet at CRT, and he ordered one at PTC.
Next one, i ordered directly at PTC, filled in the complete sspec sheet, explained to them on the phone, and the one i got was completely wrong.
OK, phoned them again, send it back, wich cost me 300$, send them the UPS tracking number. Guess what, it was delivered 4 weeks ago at their shop.
After 3 weeks off calling and emailing, they ask when do i send it to them?????? And now i even have to pay for the shipping back.
i don't think i will order there again.

I must say that the first one i ordered there was spot on.
 
Well, not if you are outside the USA. I ordered one for my Coronet at CRT, and he ordered one at PTC.
Next one, i ordered directly at PTC, filled in the complete sspec sheet, explained to them on the phone, and the one i got was completely wrong.
OK, phoned them again, send it back, wich cost me 300$, send them the UPS tracking number. Guess what, it was delivered 4 weeks ago at their shop.
After 3 weeks off calling and emailing, they ask when do i send it to them?????? And now i even have to pay for the shipping back.
i don't think i will order there again.

I must say that the first one i ordered there was spot on.
Oh man! First I have ever heard of any issues with PTC. I wonder if Covid times have anything to do with it. Sorry for your troubles. I had a similar bad experience about 3 yrs ago with Dynamic (before I went with PTC) and everyone had said so many good things about them. I guess any company can have a bad day...
 
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