Should I replace the stock converter?

[Sendero]

I have my 727 out of my 70 Charger RT. It had alot of miles on it but was ok. While I am going to have the tranny rebuilt with a Transgo 2 kit, I was wondering if reusing my stock converter is smart? Alot of "change the converter" threads but they seem to be doing it more for race purposes.

I have a mild build 440 with A/C ( Hughes Muscle car cam profile HMC 1414 BL, Comp valve job, stock intake and exhaust,stock 14 inch wheels with 3.23 gears....is a new converter going to buy me anything substantiial with this combo or is it just "best practice" to replace the converter? If I need one I'll get one but if there is no benefit over my old stock converter then I'll just reuse my old one. The car will see street use with an occasional race or two per year for fun. Long hauls to the big shows are very likely.

[Chryco Psycho]

I would change the converter , yoiu can get a 2000-2400 converter for relaively cheap  the old converter could be full of debris from the old trans & may wash it all into the new trans , it needs to be flushed out before reusing it at a bare minimum

[owatajrkiam]

The h.p. stock converter is a great piece of work,the engineers done their homework,some converters from the 383,s stalled around 2,600 r.p.m..I don,t know of another manufactuer who even came close to this in their hp cars.These coverters were built for all around driveability in mind.Tow a boat,get reasonable fuel mileage,reliable enough to get you home every day and still get it on with that slackrolet.Add headers,a cam with lots of duration and maybe a single plane man.You've effectively killed all of the torque in the lower range and you now have to raise that r.p.m..Performance could actually suffer if you dont raise the r.p.m to get it in the proper ZONE.I would strongly advise getting any advise from any of us.Go directly to the experts,B+m.Coan,etc.talk to them,give 'em your info on "You're" car.and they are gonna hook you up.Many of us seem scared to talk to them because they feel that they are going to sell us that 800.00 cant live without it,newest flavor of the week converter.Thats the farthest from the truth.Let them know you are on a budget and they will definately work with you.That info that Joe,or Pete,or Jim or whoever may differ by some saying "2400,2600,2800 even up to 3650"we are only guessing.Talk to anyone with a serious race car,especially the ones in the stock classes,and this is one of the best,bang for the buck,mods you can get.There is a lot more to converters than "Stall".I know i' m probably gonna get some flak over this because i know this is a disscussion board and we help each other here so much it is just Great.But here goes.From the info i have got from you,i would say around the 175k or 2400-2500 area as you're 440 is probably making tons of torque in this area and this will be plenty to get these heavy cars moving..A better question might be,can you turn me on to some one that you had a good experiance with and who will stand behind me if,or when i have a failure.Oh by the way,"ya know them 89.00 3500 stall converters that are out there"Stay away or at least get a good shrapnell blanket to wrap around you,re tranny.Talk to the converter guy,s then post what they had to say and let us know who was helpful to you and what they recomended.Good luck.Glen

[firefighter3931]

I would change the converter , yoiu can get a 2000-2400 converter for relaively cheap  the old converter could be full of debris from the old trans & may wash it all into the new trans , it needs to be flushed out before reusing it at a bare minimum

Everything else is fresh, why chance it with a worn part that's bound to be full of debris as Neil says. PTC makes a really nice 2400 stall 11in converter that's reasonably priced at $250.00....i plan to run this on my 70 6-pack car when it gets warmed over a bit. Cope Racing Transmissions carries the PTC line. Give CRT a call and ask for John.

http://www.coperacingtrans.com/


Ron

[sext7366]

my 70 383 single plane headers and four barrel have a 2800 stall...and its worth it while this may be a bit high for you my engine is otherwise stock minus some modifications as I said single plane, headers, high performance 440 cam, and soon to have 3.55 gears, oh and forged pistons.  If you do change though give it some time.  At first It seemed like the engine was revving too high, but after I got used to the sound and the new feel, I noticed it took off the line much better, and gas mileage has not been affected, or at least was an unnoticeable change.  Before the converter it always seemed to me that once I hit second gear I was in business, but now its all the time baby! I also reccomend a change. 

[Sendero]

PTC 11 inch on its way! 

[firefighter3931]

PTC 11 inch on its way! 

Good choice 

Ron

[Sendero]

OK the PTC converter arrived  ( quick!) but my 70 flexplate does not fit the new PTC Torque Converter. I assume I need a new flex plate. If so.,..which one? I assume since I am internally balanced with the new engine rebuild that the PTC Torque Converter is neutral balanced and that a new flex plate would be neutral balanced as well.

[firefighter3931]

The factory 440 converter is 11 3/4 in with an 11in bolt pattern. The PTC is a 10 3/4 (commonly referred to as an 11in) that will have a 10in bolt pattern. So, that's where the mismatch is. Any 383 or smallblock flexplate will work because those all have a 10in bolt pattern.

Some aftermarket converters will use a larger bolt for attachment to the flexplate. Question ; does the stock bolts that came off your old converter bolt onto the PTC unit ? If so, then you're good to go with a smallblock/383 flexplate. The other option is a B&M flexplate which is much stronger but those cost around $75.00 at Summit and are SFI rated.

See if the factory bolts work in the PTC converter and report back. Once we know what you've got things will fall into place. Also, put a tape across the bolts to verify the 10in bolt pattern.

Ron


Edit : MP part # p4876821 is listed as a 5/16in bolt flexplate for use with the MP torque converters which are all 11in diameter with a 10in bolt pattern. If the PTC uses the stock 5/16 bolts then this plate will work. If the PTC converter uses the larger 7/16 bolts them the mp # P4529751 flexplate will fit. The B&M flexplate part # is 10230 and it works with any sized converter with both the 5/16in and 7/16 bolts. 

[Sendero]

The PTC instructions state the need to drill out the flywheel for 7/16 bolts  so that is what I need for a flexplate

The bolts from my original TC/flexplate are 7/16th and thread in fine to the PTC converter so it appears that the 70 440 Magnum tranny came with 7/16 bolts converter bolts from the factory. A 10inch flexplate with 7/16 bolt holes is all  I need .... mp # P4529751

[firefighter3931]

Well Sendero, sounds like you're on the right path....good luck with the install. 

Ron