8 1/4

[7duster4]

I have a 8 1/4 in my 1974 Duster. It is the original 2.76 open. I have decided I want to go with a 3.23 sure-grip. Not a 3.55, or 3.90. I feel these will be the most comftorable. My question is how much of a difference be performance wise over my 2.76 open. My 318 and transmission have been rebuilt with modifications. Everyone tells me I will notice a huge difference. Anyone else here have this in there rear-end. Thanks

 

[BubbaCuda]

I just installed my 8 1/4 3.21 suregrip this weekend but have not driven the car yet. i still need to finish the front end disc conversion... I believe the gears will be 3.21 not 3.23.. I asked for 3.23 when i had it rebuilt but was informed those gears are for 8 3/4.
Harold

 

[7duster4]

Randys ring and pinion sell the 3.21 gears for the 8 1/4. From what I have been told they are exactly the same as 3.23

 

[rumblefish360]

The .02 will never be noticed. It is a nice upgrade from 2.76's. A good all around street gear on the lower end of the performance table.

 

[340mopar]

Going from 2.76 to the 3.21 will gain about a tenth or so in the 1/4 mile. Going from the 3.21 to 3.55 will only gain about half a tenth or less. What it really does is it can make a car feel snappier because the engine is in a more desireable RPM while cruising.


Chuck

 

[rumblefish360]

oh, SLIGHTLY OFF THE LINE QUICKER AND A SLIGHTLY LESS TOP END SPEED.

tHERES CALC'S ON LINE FOR THIS.

 

[7duster4]

A tenth is all I would gain in the 1/4? It's probably not worth the money then. I have heard from other people that a modification like that would easily knock a second off my elapsed times. Considerering my other mods, bored .30 over 318, new pistons raised to "0" deck, for barrel carb and intake, 340 cam and vlave springs, ECU orange box, port and polish, valve job, stock heads now have much better flow than before. I figured a 3.21 posi with this set up would get me under 15 seconds.

 

[MOPARJ]

A tenth is all I would gain in the 1/4? It's probably not worth the money then. I have heard from other people that a modification like that would easily knock a second off my elapsed times. Considerering my other mods, bored .30 over 318, new pistons raised to "0" deck, for barrel carb and intake, 340 cam and vlave springs, ECU orange box, port and polish, valve job, stock heads now have much better flow than before. I figured a 3.21 posi with this set up would get me under 15 seconds.

High 14's, low 15's should be easily obtainable, but not much more. That would be very good for the package. I am around 15.4 with my 2.76 open and XE268 cam.