727 vs 904

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rumblefish360 said:
Not trying to be a jerk but your wrong. There often the same is wrong. The 727 & 904 are different lengths. There is a truck/RV 727 that is longer than the standard 727.
There is also hood differences. And then U joint size.
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rumblefish360 said:
Not trying to be a jerk but your wrong. There often the same is wrong. The 727 & 904 are different lengths. There is a truck/RV 727 that is longer than the standard 727.
There is also hood differences. And then U joint size.
Click to expand...
 
Took me a minute to get it. Lol. If I am right going s6 to v8 and using a v8 904 I do not have to cut the driveshaft. Putting an 8 3/4 rear in place of the 7 1/4 I have to change the u joint to a 7260/7290. Am I close? Thanks.
 
I'd sure love to hear an answer to kegr's question, as this may be the route I take. Either that, or keep the A727 that is in it. I'm assuming it has an A727 right now. Was that the trans that was put in by the factory for a Slant 6 in '68?
 
BarracudaWild68 said:
I'd sure love to hear an answer to kegr's question, as this may be the route I take. Either that, or keep the A727 that is in it. I'm assuming it has an A727 right now. Was that the trans that was put in by the factory for a Slant 6 in '68?
Click to expand...
 
The 904 was put in 6 cylinder and 318 cars. The 340 as far as I know was the only engine backed by a 727. As far as small blocks go.
 
727’s also backed /6 & 318’s.


kegr2010 said:
Took me a minute to get it. Lol. If I am right going s6 to v8 and using a v8 904 I do not have to cut the driveshaft. Putting an 8 3/4 rear in place of the 7 1/4 I have to change the u joint to a 7260/7290. Am I close? Thanks.
Click to expand...
Question 1, correct
Q2; It’s not the U joint that’s an issue. IF there are two different U joints sizes between the rear and drive shaft, several companies make U joints that are half 7260 & half 7290. Check Mancini Racing.

Going from a 727 to a 904, the holes that slide into the transmission are splined different. The yokes can come in both U joint sizes.

Each MoPar rear has a different length nose, the driveshaft has to be cut down.
Also, the 727 & 904 are different lengths.

Not all driveshaft shops will tell you measure the driveshaft length from the flat of the yoke on the rear to the flat of the transmission and also the amount the transmissions shaft comes out of the rear, but generally that’s how it’s done. Sometimes they want you to slide in the yoke and pull it out 1-1-1/2 inches and measure to that mid point of the yokes U joint hole.

This is all easy and all you need is a bud to hold the cam ape measure at 1 point. You read the number and fraction.
 
All great info, guys. So, my Signet will have the lighter 904. Great! Since someone mentioned that it can handle 500+ hp, I can keep the numbers-matching trans. I just don't want to keep the Slant 6. I feel a little bad about breaking up a #s-matching car, even if it is a lowly Signet.
 
Just incase you did t know…/

You can’t use the /6 trans with a small block.
Transmissions are engine specific.
You’ll have to find a small block transmission.
 
Ohhh! Hmmm . . . I can buy one from A & A. I wonder how much, in a ballpark figure, a 904 that can handle 500+ horse cost me? Anybody got a rough guess?
 
There roughly in the same price range.
Small potatoes. Go for the gravy instead.
 
What's in the same price range? The 727 and the 904? I'll go for the best for the money I can afford right now.
 
Does anybody have a rough guess as to how much one of these trans would cost? Thanks.
 
It will be cheaper than I thought! Wonderful! Now, I just need to find a great 340 block and buy a stroker kit.
 
500 horse? No. About half that. Most small block 727s won't handle it either. And the two barrel 383 won't either.
 
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