904 or 727 Trans for 375 hp?

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stop the beast

stop the beast

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I'm starting to plan for a 318 or 360 swap in my '66 dart. I want to build it for 350-375 hp depending on the costs once I get into everything.

The dart currently has the stock 904. Can the early 904 be built for the sort of torque this power level is going to make? I'm assuming 350-400 ft/lbs. I've read that the 727 will bolt in with some mild massaging of the tunnel.

I've seen plenty of threads on built 904 going the distance but I'm not too interested in working the tranny a whole lot. What would a 727 need to support these power levels? Is the 727 swap a no brainer or would the 904 be okay?

Thanks
 
i like both. the 904 is lighter and in quite a few cases quicker just not quite as strong. that is not a crazy amount of power. i think the small blocks back in the day were around 250-300 horse(dont quote me lol) so i would say you would be fine. guys on here have but a bunch of power thru them and havent really worked the trans to much so i would say stick with the 904 and if it blows then you can say i was wrong lol
 
A lot will depend on what you're going to do with the car. If it's a street car,
the 904 with a performance overhaul kit would work just fine with the horsepower you're talking about. If it's drag car, you're going to have to upgrade either one. The 904 still has the advantage in most respects. It's lighter, uses less HP, and gives you room to add a tranny blanket for safety. Another plus is you won't have to change the driveshaft unless you're upgrading the rear axle too. If you have a 7 1/4, that is a MUST! A slant 6 will blow those things up! Don't forget some good brakes also.

Thanks, Mark
 
only 375 hp.. a 904 will hold up just fine in that car. just use quality parts in the rebuild and have someone that knows what they are doing do the rebuild.

on the early trans though, i believe the converter spline count is different. you would have to convert it to the newer style so you have a bigger and cheaper choice of converters...
 
stop the beast said:
I'm starting to plan for a 318 or 360 swap in my '66 dart. I want to build it for 350-375 hp depending on the costs once I get into everything.

The dart currently has the stock 904. Can the early 904 be built for the sort of torque this power level is going to make? I'm assuming 350-400 ft/lbs. I've read that the 727 will bolt in with some mild massaging of the tunnel.

I've seen plenty of threads on built 904 going the distance but I'm not too interested in working the tranny a whole lot. What would a 727 need to support these power levels? Is the 727 swap a no brainer or would the 904 be okay?

Thanks
Click to expand...

I have a 10-pound boost, Vortech-supercharged 360 in a 3,400 pound Valiant, that is a street/strip car with a mildly-massaged 904 with a Trans-G0 shift kit. I've raced this car for 4 years and abused it on the street with 445 rear wheel HP and it still shifts crisply. I've had zero problems with it.
I think a 727 is overkill for your car.

Just sayin'....:happy10:
 
abodyjoe said:
only 375 hp.. a 904 will hold up just fine in that car. just use quality parts in the rebuild and have someone that knows what they are doing do the rebuild.

on the early trans though, i believe the converter spline count is different. you would have to convert it to the newer style so you have a bigger and cheaper choice of converters...
Click to expand...

Thanks for the replies. I'll look into the converter issue and probably stick with the 904. Everything I read says it's one of the more efficient auto trans availble.
 
It's not for nothing that ProTrans bases their $$$$$$$$$$$$$$$$$$$$$$ drag racing units on the 904......:cheers:
 
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