727 low gear set - worth the investment?

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Dart 67

Dart 67

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Hi guys,

As I want to improve my quarter mile passes, and I don't have the budget to built a stroker engine, a friend of mine suggested to install a low gear set in my 727.

I would like to know if it's worth the investment and if someone here had any trouble after installing these kind of gears.

Should I expect at least low 12's for a car that runs 13.09?

Oh yeah.... I have a 3.55 with an auburn gear pro series limited slip.
The tranny is mostly stock except for a B&M transpack and a superstreetfighter 3500 stall torque

Many thanks :)
 
I have not heard of this for the 727 trans, but I did it for my 904 with a set from an A-999 trans. I had the luxury of building my entire combo and including the gear ratio of the lower gearset into my combination. If it is possible to do with a 727, and you need a quicker ramp to get your RPM's into the motors powerband, then yes by all means do it. However, you may want to debate whether a change in the rear gears will do the same thing for you. A 3:55 is a pretty mild gear, and although I don't know your particular combination, I would say that you should be running no less than a 3:73 with any smallblock, and if drivability is not an issue, you should be looking at some 4:10's. Good luck with your project, Geof
 
Its not very cost effective to put in a low gear (2.77) if you are on a budget. Unless these have come down in price, you could build a complete 904 w/low gear for the price of the gear set.
The low gear works good if your car weighs more than 3000lbs. If you went with the 904, you would also free up some horse power ( less rotating mass) plus the advantage of the low gear.
 
What is your cam?

If your engine develops peak power at 6500, and you are only turning 5000 at the big end of the track, you are never getting full power. Remember, you spend more of the pass, and cover more of the track in high gear, than in low.

Besides, a lot of the 727 low sets are modded 999 parts, perhaps not the strongest.

Try a shorter tire.
 
Definitely not worth the money, no if's ands or buts about it. If you already had the 904 then yes it would be ok because it's cheap when purchased from a used core tranny. You can't do that with the 727 as it was never offered in a production vehicle of any kind no matter what any one may tell you. They were available from Direction Connection for a time but they were expensive then in the 70's, about $700-$800. The ones available today are modified 999 pieces unless they are billet sets. Either way the billet sets are extemely expensive and the welded up 999 pieces leave something to be desired. I'd rather just have the whole 999 setup.

As has been said a steeper rear gear is a better more cost effective alternative for you.
 
Many thanks for all your answers :)

First, I realised that I did not mentionned that the car is a street/strip car. I sees the track about 5-6 times per summer (damned Canadian winter).

I did not looked for a 904 build because my 727 was rebuilt about 3 years ago and I have purchased a TCI stall. Too much money put into it to replace the tranny... for now ;-) .

I did not checked the rear gear solution. I already runs 3000rpm at 60miles on the highway. I'm affraid that the car will run too much RPM on the highway usign a lower gear. The advantage of the low gear set is that I keep my 1:1 ratio on third gear with a 3.55 in the rear.

The set I am checking is from A&A http://www.aandatrans.com/Departments/Chrysler-727-Trans/Low-Gear-Sets.aspx

C130 Chief: My cam is designed to go in the 6000rpm range.
Here are the specs:
Cam Brand: Mopar purple cam P4452992
Valve Lift Intake and Exhaust: .474/.474
Advertised Duration: 280/280
My RPM at the finish line is around 5200 RPM

Any other comment or suggestion is welcome 8)
 
I run a special low set, they are nice for a street strip car, i run 3.91s and it is like runing about a 4.30 out of the hole, with a big block or stroker the torque will get you buy good since since the 1-2 drop is steep, and then you have the advantage of your 3.55s on the highway.

But yes big bucks...

PS I ran this in the 727 even with my 4.30s and a 273, helped launch the 60' time very nice.
 
Guitar Jones said:
You can't do that with the 727 as it was never offered in a production vehicle of any kind no matter what any one may tell you. .
Click to expand...

I watched Darin Rumpel pull them out of a late '60s light dump truck tranny at Sharadon Performance myself.
 
Ok, I will try to change the gear instead of playing with my tranny.

I will try a 3.91 gear. :toothy10:

Does this modification will increase my RPM at 60 mph a lot?
I already do 300rpm at 60 mph.
 
Dart 67 said:
Ok, I will try to change the gear instead of playing with my tranny.

I will try a 3.91 gear. :toothy10:

Does this modification will increase my RPM at 60 mph a lot?
I already do 3000rpm at 60 mph.
Click to expand...

It will increase you to approximately 3300 rpm's at 60 mph.
 
Guitar Jones said:
. You can't do that with the 727 as it was never offered in a production vehicle of any kind no matter what any one may tell you. They were available from Direction Connection for a time but they were expensive then in the 70's, about $700-$800. The ones available today are modified 999 pieces unless they are billet sets. Either way the billet sets are extemely expensive and the welded up 999 pieces leave something to be desired. I'd rather just have the whole 999 setup.

.
Click to expand...

http://chucker54.stores.yahoo.net/lowgearsets.html

low gear sets for 727 and 904... no welded up pieces
 
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