Those of you who've swapped a 518 42RH behind a small block, who's torque converter did you go with? I'm looking for something with a 2500 stall. Are they the same 23 spline torque converter that's used on the 727?
Torque converter for 42RH swap
- Thread starter Mike D
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You can contact Precision. Precision of New Hampton
Bobzilla
Well-Known Member
Please clarify which transmission your are actually dealing with, asking about. The 42RH in the title is not the same as an A518 in your question.
The A500 is the smaller four speed overdrive kind of like a 904, and later got named as a 42RH and then 42RE.
The A518 is the larger four speed overdrive kind of like a 727 and later got named as a 46RH and then 46RE.
Most of these torque converters are NOT interchangeable.
transman
Well-Known Member
Nope not the same.
A500 42RH 26 splines--like the 904
A518 46RH 24 splines--like the 727
727 Early 19 splines
727 Late 24 splines
Converter will have to be balanced to match your engine. All A500's have no weights, A518 may or may not have weights. High stall should not be an issue, but you will need to contact one of the known high stall builders as speak to them.
roadrunninMark
Well-Known Member
Transman, do all converters need to be balanced to each engine anytime you put in a different converter? I am changing a trans behind a 318 and a 340. What about the flex plate?
transman
Well-Known Member
Ok, here's the information I have:
With the 727:
318 Engine. Will have a narrow ring gear(12" Dia.), and No Weights: Application 1967 to 1977. Crankshaft: Steel. Also found behind 383 & 400 engines.
340 Engine: Will have a wide ring gear(11" Dia.), and will have two weights that measure .88" x .62" x .177". Application 1969 to 1973. Only found behind 340 engines.
This information comes from the catalog I used when I worked in the industry Mark. While we had thousands of converters, both rebuilt and cores, any one looking to purchase a 340 converter had to supply a 340 core, as they could at times be difficult to source. The stall speed on the 340 converter was in the 2200/2450 rpm range.
I believe that B & M have a flex plate you can use on a lot of different applications. I've seen it mentioned here many times, but I have no information on it, but I'm sure others will.
Where I worked, we only carried stock Chrysler flex plates, or SFI approved ones for the race crowd. I've attached a file, showing the 4 flex plates that Chrysler used for ALL engine and transmission combinations.
Now if you're going to put an A500 or the A518 behind the 318 or 340, you've opened up another area totally. I have had no experience in this area, and perhaps somebody who has put the OD transmission behind the 318/340 engines can tell you what you will encounter.
I hope this information is helpful.
roadrunninMark
Well-Known Member
Thanks Transman for the excellent info.
plumkrazee70
Well-Known Member
I have a 42RH with lockup, behind my 340, which is internally balanced (no weights). I purchased a biltrite converter with 2800 stall and so far so good. It goes, when the pedal is pushed and cruises nice. I don't have a ton of run time yet, though.
roadrunninMark
Well-Known Member
Plum, so it depends how the engine is balanced? You internally balanced the engine so the convertor can be "neutral balance". Is that correct?
plumkrazee70
Well-Known Member
Correct. In my case I have a 68 340, which has a forged crank (internally balanced.) I have no weights on the harmonic balancer and no weights on the converter or flexplate. I do believe if you need a weighted converter, you can opt for a weighted flexplate.
What motor you running?
roadrunninMark
Well-Known Member
I am running a 71 318 with stock crank and rods, new balancer for a 318. Build will be like the Hot Rod mag. "Junkyard Jewel" but with retro roller cam and aluminum heads.
My friend is running a 73 340, external balanced with original harmonic balancer and I believe a B & M flex plate. He said it has a neutral balanced converter so his flex plate must be externally balanced to his combo then (he didn't build it, just recently bought the car).
The reason I am asking is because we are both going to do the 8hp70 behind our small blocks and I making sure we have all the info we need. I thank you guys for supplying that info.
Some other stuff I need to know: stock 8hp70 flex plate and torque converter - are they neutral balanced or external balanced? Can I tell by looking at them? I have one on the way to me now, be a little while before I get it to look at the parts.
My friend is running a 73 340, external balanced with original harmonic balancer and I believe a B & M flex plate. He said it has a neutral balanced converter so his flex plate must be externally balanced to his combo then (he didn't build it, just recently bought the car).
The reason I am asking is because we are both going to do the 8hp70 behind our small blocks and I making sure we have all the info we need. I thank you guys for supplying that info.
Some other stuff I need to know: stock 8hp70 flex plate and torque converter - are they neutral balanced or external balanced? Can I tell by looking at them? I have one on the way to me now, be a little while before I get it to look at the parts.
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plumkrazee70
Well-Known Member
8HP70? Is the new 8sp trans? I thought we were talking about 42RH. Lol.
roadrunninMark
Well-Known Member
It is, we were talking about the 42RH but I am using the info towards the other project too.
plumkrazee70
Well-Known Member
Oh, I'm sure that 8HP70 is a whole nother animal. That thing looks gigantic. Major tunnel mods, but Im sire it can be done.
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