Poll: Lucy - Should I Modify Her Engine?

[Carlwalski]

Hey guys, talked to the shop today and I told them I was going 4.30 C&P. After looking at my old invoices my rear end 3rd member has 29 spline axles, not a problem, I will purchase new 30 spline axles to suit my new Detroit TrueTrac posi but I am stuck. Randy's Ring & Pinion have 2 available 30 spline axles for E-Bodies and instead of taking the car in and removing one I thought I would ask. See links below, 1st link states E-Body measuring 28"-32" and the other link also states E-Body but 30" axle, what one do I need/have (stock Chrysler 8-3/4" differential).

My thoughts are they could be 'Cuda and Challenger as the 'Cuda was 2" wider, but I doubt they added length to the 'Cudas axles, etc, way too much effort, time and money for Chrysler to do that back then. Any help is much appreciated. Also, while I'm at it, what length rear wheel studs do our cars have, I basically need confirmation. I'm 90% sure they are RH Thread. Year One states them for E-Bodies as: "RH wheel studs 1/2"-20 x 1-19/32" with .673" knurl diameter. Correct for RH side but will work on LH." This is what I got last time, this is correct, yes?


Thanks guys,
Carl



http://www.ringpinion.com/ProductDetails.aspx?ProdID=5641

http://www.ringpinion.com/ProductDetails.aspx?ProdID=5640



Ps: Some photos I took today............

[hemiken]

Hey Carl, unless someone has swaped your diff with a ford 9 inch, their is no way your axles will be 29 spline.  8 3/4 only have 30 spline, someone has miss counted your spline on the axles buddy.

[71chally416]

 

[Carlwalski]

Thanks guys but I probably should have said (my bad) I purchased a Randys Ring & Pinion built 3rd member with 29 splines a while back when I got my new 3.91 gears, must be about 18 months ago now. So I will be getting 30 spline axles, green bearings and a new posi (can't stand the clunking of this non truetrac) but I'm not sure what one to get.

[Super Blue 72]

Great looking pics, Carl! 

[Carlwalski]

Thanks mate.



Lucy is in at the shop for a WOF, new MP hi-torque mini starter and to have her splines double checked. Only way to be 100% sure. One of the original owners (back in the mid 80s) removed the factory 3.55:1 3rd member and replaced it with something else, possibly a Valiant section that had 2.76:1 gears. This is why I ordered a new 3rd member from Randy's Ring & Pinion. They sent a 29 spline unit. I will know today what I need.

[Carlwalski]

It was indeed 30 spline, I saw 29 spline on the invoice which must be the yoke spline count? Anyhow, glad we puled it out to double check. I have already ordered my TrueTrac, just considering gears...4.30 or 4.56, not sure what to get. 4.30's would be good but they are out of stock.

[71chally416]

I thought you had some freak 3rd member. 

[Carlwalski]

So did I. Glad I don't cause now I don't need new axles, bearings and studs. I will let you guys know how I get on and my opinion on the gears for future searches it may help others out with "sluggishness" issues that could be fixed by a new R&P.

[71chally416]

If it helps I've never driven a street car with a 4.56 rear that was "Sluggish", and I've had a few.  A bit hard to drive 60mph without an OD tranny, YES, but not sluggish off the line.  

[Carlwalski]

4.56 with my .078 final drive with GVs equals 3.56 which isn't too bad, about the limit in my opinion for an all round street car. But at this stage I'm thinking stay with 4.30s, still a great launch and throttle response around town and still cruising like a 3.35 car.

[JS27N0B]

4.56 with my .078 final drive with GVs equals 3.56 which isn't too bad, about the limit in my opinion for an all round street car. But at this stage I'm thinking stay with 4.30s, still a great launch and throttle response around town and still cruising like a 3.35 car.

I'd recommed staying with 3.91's or 4.10's  You have a torque motor there that does not have high RPM breathing ability and will quickly run out of air. I had 4:89's with a warm 440 6pk and it did work well but didn't really pull hard till you got it into 3rd gear. This is what I am basing my opinion on, it was much faster with 3.55's but didn't put on aywhere near as good a show!

[Carlwalski]

Thanks Shaun, information has been taken into account. Problem with my 3.91s is the car doesn't even squeal the tyres, you have to really make them squeal if you want to so I feel safe knowing the traction limit of Lucy hasn't been reached yet. If I did go 4.10s I feel the difference would be minimal, if I could tell at all. I'm sure I could tell but the effects would be minimal. IMO, 4.30s offer a good difference while still being a reasonable cruising gear (3.35:1). I'll be calling Randy's tonight to see how long the 4.30 is on BO for. Thanks for the input.

[JS27N0B]

Thanks Shaun, information has been taken into account. Problem with my 3.91s is the car doesn't even squeal the tyres, you have to really make them squeal if you want to so I feel safe knowing the traction limit of Lucy hasn't been reached yet. If I did go 4.10s I feel the difference would be minimal, if I could tell at all. I'm sure I could tell but the effects would be minimal. IMO, 4.30s offer a good difference while still being a reasonable cruising gear (3.35:1). I'll be calling Randy's tonight to see how long the 4.30 is on BO for. Thanks for the input.

Fair enough

[METAL BEE 68]

Its your car, so do as you please. I say GO FOR IT! The way I see it, whos going to care in 50 years anyway?