Ring and Pinion question for 65

SoFlakid · 10-27-2012, 01:13 PM

I have a stock ford 8.8 rear end in my 65 coupe which i believe has a 2.88 gear set in it. Stock bottom end 289 w/ 302 heads,edelbrock air gap intake with 550 carb. I've been looking at a 3.55 gear set, just wondering what you guys think?
Highway driven a few days a week, need to go faster than the 65mph i can only go now.

any input is appreciated, thank you!!

frdnut · 10-27-2012, 02:06 PM

Why can you only go 65mph now?..Gearing lower with the 3.55s will give you better acceleration but theoretically would give you a little lower top speed...Having said that either gear set should run much faster than 65 mph..

What year 302 heads did you put on your 289?..Almost all 302 heads have bigger combustion chambers which will hurt power on a stock 289..

HoustonGlock · 10-27-2012, 03:20 PM

What makes you think the rear axle is an 8.8" ?
The factory V8 rear was an 8" removable carrier. The 8.8 didn't come along until the 80's and it's an integral carrier, same as all the late model Mustangs.

SoFlakid · 11-20-2012, 12:34 AM

Why can you only go 65mph now?..Gearing lower with the 3.55s will give you better acceleration but theoretically would give you a little lower top speed...Having said that either gear set should run much faster than 65 mph..

What year 302 heads did you put on your 289?..Almost all 302 heads have bigger combustion chambers which will hurt power on a stock 289..

Well im honestly not sure, it sounds real loud on the highway at about 70mph. i have the stock 2:80:1 rear end. whats the top speed on that?

im honestly not sure about the year, i believe they were off of a cobra. I know i lost compression, im putting in a xe268h cam and im trying to find pistons to put in, any suggestions on pistons?!

HoustonGlock - i assumed it was an 8.8 but you are most likely right! so lets say its a 8 then. sorry!

beechkid · 11-20-2012, 12:52 AM

Quote:

Originally Posted by SoFlakid

Well im honestly not sure, it sounds real loud on the highway at about 70mph. i have the stock 2:80:1 rear end. whats the top speed on that?

HoustonGlock - i assumed it was an 8.8 but you are most likely right! so lets say its a 8 then. sorry!

Assuming you are running stock tire size (185x14x70) or equivalent diameter, top speed would be 100+ mph....these guys will run at 80 mph all day long. FYI- for each .25 gear ratio change, the rpms will change by 300.

BTW, IMHO I would not run a Comps Cam for anything...too many QA issues ranging from their chinese cast billets to machine work. Highly recommend Iskenderian, Crower, lunati, Howard....

SoFlakid · 11-20-2012, 03:50 AM

im running 205s in the front and 215s in the back.

Could it be a transmission or tuning problem that is leading to my poor top speed?

tx65coupe · 11-20-2012, 07:31 AM

This is just my two cents, but I wouldn't want any more than 3.20 gears with a non OD transmission.

bartl · 11-20-2012, 08:06 AM

I have 215/65-15's in back, a top loader and 3.00:1 rear axle and still have a bit left at 125mph.

09Frank65 · 11-20-2012, 08:37 AM

Changing to 3.55's will reduce your top end speed. With the 2.88's you should be able to run all day long. I don't think you mentioned what tranny you have or what your final gear ratio is but you have to consider the entire drivetrain. It would be good to know what RPM you are actually at when you are at 65 MPH. There is no way you should be topping out there with 2.88 gears.

Before all the changes, my bone stock 289 used to hit a wall (so to speak) at 95 MPH with the 2.78 gearset. It just ran out of air.

Love your coupe by the way. The color is awesome.

22GT · 11-20-2012, 08:53 AM

Quote:

Originally Posted by HoustonGlock

What makes you think the rear axle is an 8.8" ?
The factory V8 rear was an 8" removable carrier. The 8.8 didn't come along until the 80's and it's an integral carrier, same as all the late model Mustangs.

Yep. The 8.8 was not invented until decades later, the normal V8 axle in 65 was the 8". A huge difference between the two. The only thing they have in common is the pinion yoke nut.

SoFlakid · 11-21-2012, 04:05 PM

Quote:

Originally Posted by tx65coupe

This is just my two cents, but I wouldn't want any more than 3.20 gears with a non OD transmission.

Well i appreciate your 2 cents! would you mind telling me why?

Bartl - well thats interesting, what do you think my problem is?

09Frank65 - I'm not sure what the tranny is, but its a 3 speed automatic. On a few occasions when ive been driving on the highway, it feels like the motor is tugging back some, like literally pulling back some, its weird. Im not sure if it has gone away with new heads or not. im installing a rpm gauge now to find out what im revving at 65. And Thank you!! i appreciate it, didnt think many liked it.

horsehead · 11-21-2012, 05:41 PM

Are you sure the trans is shifting into high gear? Can you feel it shift into high gear? A tach will help you know more for sure. Let us know but with those gears , tires, trans, etc. you shouldn't be over 2800 it seems. More like 2500-2600 at 65 MPH. Also FYI---your probably running now 2.80 or 2.83 gears now. Never heard of 2.88's myself--.

22GT · 11-21-2012, 06:30 PM

Quote:

This is just my two cents, but I wouldn't want any more than 3.20 gears with a non OD transmission.

Quote:

Originally Posted by SoFlakid

Well i appreciate your 2 cents! would you mind telling me why?

Have you ever gone for a long drive with a 3.89 or 4.11 rear? I have. The whine of the engine running at 3000 rpm gets to you after a while.