Author Topic: diffs (Read 3933 times)

pud · « **on:** October 25, 2008, 10:13:30 AM »

Hi. I have a 64 corvette and Im trying to find out what the diff gearing is. the no. on it is 1AP112668W. Once I find out the size, I want to change it to lower the revs on the cruising speed. at the present time, its revving at 3500 at 110 kmh ( the Aurion does 2000 revs at 110 kmh) and as I spend most of the driving time on open roads, its becoming a bit expensive. Its got ample grunt but it just feels sometimes like I am driving a four wheel drive in low range.
any suggestions would be greatly appreciated.

pud

nifty · « **Reply #1 on:** October 25, 2008, 04:02:52 PM »

easiest way to get a rough guesstimate is to jack up both wheels, turn them 2 full rotations, and count the number of turns the tail shaft does..... eg, it the shaft turns a tad over 3 turns it would be 3:08 gears..... etc etc....

gtc · « **Reply #2 on:** October 25, 2008, 04:13:21 PM »

I'm not a C2 series expert, but according to the book Corvette by the Numbers, that's a 1968 diff.

AP = Positraction 4.11:1
11 = November
26 = 26th day
68 = 1968
W = Warren, MI assembly plant

The highway diff option (3.08:1) has code "AL"

nifty · « **Reply #3 on:** October 25, 2008, 07:22:43 PM »

Quote

Originally posted by gtc
I'm not a C2 series expert, but according to the book Corvette by the Numbers, that's a 1968 diff.

AP = Positraction 4.11:1
11 = November
26 = 26th day
68 = 1968
W = Warren, MI assembly plant

The highway diff option (3.08:1) has code "AL"

hwll if its a 4:11 no wonder its revving.....more suited to the drag strip.

pud · « **Reply #4 on:** October 26, 2008, 07:02:16 AM »

Thank you for that information gents. I will try rotating the wheels just to make sure but the way it revs now, it does seem like somebody wanted to make a quick getaway.
Thanks once again.

pud.:ado

nifty · « **Reply #5 on:** October 26, 2008, 10:27:20 AM »

Quote

Originally posted by pud
Thank you for that information gents. I will try rotating the wheels just to make sure but the way it revs now, it does seem like somebody wanted to make a quick getaway.
Thanks once again.

pud.:ado

being i lsd BOTH WHEELS MUST BE JACKED OFF THE GROUND, normally a single wheel will do the job.

BOSCHVETTE · « **Reply #6 on:** October 26, 2008, 09:21:17 PM »

Yep i agree it is definately running 4.11 gears which should give it plenty of punch.
i would keep those gears if it was me but it depends what you use the car for.i dont give a stuff about fuel costs it takes fuel to make horse power so the more fuel it uses the better it is i recon.

pud · « **Reply #7 on:** October 27, 2008, 08:22:03 AM »

I copy that but I use it mostly on the freeways and its mostly 100 k areas around here so it runs out of juice before I can give it some grunt.

WARFARIN · « **Reply #8 on:** October 28, 2008, 08:44:12 PM »

Get an over-drive transmission! 4-speed auto or 5-speed manual and get the best of both worlds!