La360 and 727

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74@scamp

74@scamp

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Ok I am new here and have done a couple google searches and a couple searches on here to try and find the answers needed. Hopefully somebody can help. I have a 74 plymouth scamp that came with a 1979 360 motor. I am trying to find a 727 transmission to go with it. Do all small block 727 and 727 torque flight transmissions share the same bolt pattern and have the same spline count? I would love to find a torqueflight but haven't found one yet
 
Big block, small block, and slant 6 all use different bellhousing bolt patterns. You need a smallblock 727.
Input splines were different between standard 727s and ones with a lockup convertor (late 70s-early 80s?). Output splines are all the same, as is the overall length.
Stay away from '65 and earlier transmissions- output used a flange for a ball and trunnion, had cable shift, and a different speedo drive.
Also some HD truck and motorhome trannies had a stubby tailshaft, and/or a flanged output or parking brake drum- but those are readily obvious.
More importantly, most smallblock 727s will have a neutral balanced convertor- your 360 requires an externally balanced (LA 360 only) convertor, or an aftermarket externally balanced flexplate.
 
As Prof. Fate stated smallblock A727's as well as V8/V6 904's all share the same bolt pattern
If you're lucky and can find one, an A998 or A999 out of a 1980's M-body or 2WD Dakota is a great transmission as well. They're basically beefed up 904's with wide ratio gears.
 
Professor Fate said:
Big block, small block, and slant 6 all use different bellhousing bolt patterns. You need a smallblock 727.
Input splines were different between standard 727s and ones with a lockup convertor (late 70s-early 80s?). Output splines are all the same, as is the overall length.
Stay away from '65 and earlier transmissions- output used a flange for a ball and trunnion, had cable shift, and a different speedo drive.
Also some HD truck and motorhome trannies had a stubby tailshaft, and/or a flanged output or parking brake drum- but those are readily obvious.
More importantly, most smallblock 727s will have a neutral balanced convertor- your 360 requires an externally balanced (LA 360 only) convertor, or an aftermarket externally balanced flexplate.
Click to expand...
Thank you so much for all the info, I appreciate it. My plan was to use an updated external balanced flex plate. The la360 I have is a 79, would be nice to find a 727 around that same year.
 
Cuprum-74 said:
As Prof. Fate stated smallblock A727's as well as V8/V6 904's all share the same bolt pattern
If you're lucky and can find one, an A998 or A999 out of a 1980's M-body or 2WD Dakota is a great transmission as well. They're basically beefed up 904's with wide ratio gears.
Click to expand...
Got ya, thank you, I will do some looking
 
So I finally got around to pulling my automatic transmission today. Turns out it is a 1972 904 transmission. Curious what flex plate and torque convertor I need to mount it to my 1979 la360?

Or would I be better to sell the 904 and find a 727
 
i'm a little confused... you have a 72 904 that goes with or was attached to the 360?

if you have that, what's wrong with it? why do you want a 727?
 
No matter, they (727) are a better trans. Don't blame the guy for going that way
 
junkyardhero said:
i'm a little confused... you have a 72 904 that goes with or was attached to the 360?

if you have that, what's wrong with it? why do you want a 727?
Click to expand...
Sorry, that was confusing, I have a 72 904 that came from the factory behind a 318, the car I bought came with a la360 on an engine hoist
 
the low-buck move would be to build the 904 out, and get a proper converter that's already weighted.

the other option would be to sell or trade the 904 (+ cash) for a 727 and then sort out the converter and flex plate. but then you're still in the boat of [likely] needing to build a trans and buy a converter.

so it's kind of a 6 of one situmanation with the added expense if you want a 727

and yes, a 904 will live just fine behind a 360 as long as it's not some super rowdy build.
 
Yes, rebuild that 904.
Sure a 727 is stronger but not necessarily the better option. As stated before, you'll have to sort out a torque converter, and on top of that you'll need to shorten your driveshaft.
A 904 with a good HP rebuild kit can handle a mild 360 easy.
Heck the guy who helped me rebuild my A999 is very confident that my trans can handle a 408 stroker. And he's been rebuilding these transmissions, as well as building ones for racing for over 30 years, I'm glad I got to pick his brains.
 
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Cuprum-74 said:
Yes, rebuild that 904.
Sure a 727 is stronger but not necessarily the better option. As stated before, you'll have to sort out a torque converter, and on top of that you'll need to shorten your driveshaft.
A 904 with a good HP rebuild kit can handle a mild 360 easy.
Heck the guy who helped me rebuild my A999 is very confident that my trans can handle a 408 stroker. And he's been rebuilding these transmissions, as well as building ones for racing for over 30 years, I'm glad I got to pick his brain.
Click to expand...
Thank you for the great info. I figured I would have to change the driveshaft, might upgrade the axle at the same time to something a bit stronger. Next question is who would I contact to find the correct torque convertor and flexplate? Is that something summit racing could help me get my hands on or would I need to contact a transmission shop to find the correct torque convertor that will bolt up to the flex plate?
 
74@scamp said:
So I finally got around to pulling my automatic transmission today. Turns out it is a 1972 904 transmission. Curious what flex plate and torque convertor I need to mount it to my 1979 la360?

Or would I be better to sell the 904 and find a 727
Click to expand...
You say you just pulled the 904. Did it have a torque converter?
What level of modifications does the 360 engine have? Is it mostly stock?

if your 904 has the converter and it is neutral balance for the 318 it was behind, you can bolt it right up to the 360 engine using a flex plate that has the LA 360 balance offset built into it, like a B&M part number 10239. To make it cheaper, keep the torque converter and flex plate from the 318 setup and have a qualified local trans shop or converter rebuilder add the LA360 weight to your converter.
 
Bobzilla said:
You say you just pulled the 904. Did it have a torque converter?
What level of modifications does the 360 engine have? Is it mostly stock?

if your 904 has the converter and it is neutral balance for the 318 it was behind, you can bolt it right up to the 360 engine using a flex plate that has the LA 360 balance offset built into it, like a B&M part number 10239. To make it cheaper, keep the torque converter and flex plate from the 318 setup and have a qualified local trans shop or converter rebuilder add the LA360 weight to your converter.
Click to expand...
No it didn't come with the convertor or the flexplate.

From what I can tell the motor looks stock besides an offenhouse intake.

Got ya thank you
 
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