ZL1 Differential Swap

[MA2010SS]

Originally Posted by usmcjlp

I have a question. If you are looking at spending $4000-$5000 in parts alone, why would you not move up to an aftermarket 9" kit? Wouldn't the 9" kit be much stronger?

I have a similar set up.(Whipple, Cam, Headers, 4.11s). I'm currently around 650rwhp. I am trying to decide which route is better. Does anyone have any advice?

It's around $4K for the ZL parts without somone installing it and between $6200 - $7200 for a 9" set up without someone installing it. It just becomes another option for these cars and there are a few ZL's that have run in the 9's and 10's without a problem with the rear, just something for us to look at

[Russell James]

Wonder if the cradle bushings are a direct swap over to an SS cradle?

[quincy speeder]

There are also people running 9's on the stock rear. I'd wait and see how strong these rears really are, only time will tell.

on a side note, I was at slowhawks friday, I think he was talking about your car and how much power it put's out. Very nice..

[MA2010SS]

Originally Posted by quincy speeder

There are also people running 9's on the stock rear. I'd wait and see how strong these rears really are, only time will tell.

on a side note, I was at slowhawks friday, I think he was talking about your car and how much power it put's out. Very nice..

Thanks man! I think that I am going to stick with the stock rear and go with better axles and maybe a driveshaft for now...Don had me thinking and he's right, also if the rear that I have goes, a complete 1LE differential is roughy $1400 and I would just swap that out which takes no more than an hour or so

[Steve@HPE]

Originally Posted by MA2010SS

It's around $4K for the ZL parts without somone installing it and between $6200 - $7200 for a 9" set up without someone installing it. It just becomes another option for these cars and there are a few ZL's that have run in the 9's and 10's without a problem with the rear, just something for us to look at

I priced the parts with the cooling lines and the cost was right at $5500 with a 25% discount from list price. Also, the driveshaft joint that connects to the transmission requires new bushings to accommodate smaller bolts and yoke notch.

The differential is a beast, with a cast steel case and 9.9 ring gear I suspect it's as strong as a 9".

[MA2010SS]

Originally Posted by Steve@HPE

I priced the parts with the cooling lines and the cost was right at $5500 with a 25% discount from list price. Also, the driveshaft joint that connects to the transmission requires new bushings to accommodate smaller bolts and yoke notch.

The differential is a beast, with a cast steel case and 9.9 ring gear I suspect it's as strong as a 9".

I think that the 9.9" is going to be as strong as the ford 9" it's just not a proven unit being that it's new for these cars or new in general. I've been doing a lot of thinking on this and I am probably going to stick with the stock center section for now. Upgrade the axles and DS, I have seen a lot of cars in the 10's and 9's with some decent 60' times. I already have the JRE upgraded center and if I were to grenade the center section for around $1400 on a complete new 3.91 center section 1LE style...I like having options and the more out there the more competitve the pricing gets...for the most part

[CNC73]

Waiting for the COPO rear suspension install kit, and ditching the independent rear all together, and go with a straight axle.

[Jason P]

Just finished ordering parts for my zl1 rear diff swap. Hopefully parts will be here in about 2 weeks. Will try to post pictures of install and let you know how it goes I'm also installing the diff cooler. There is not much info or pictures on the plumbing of this so when I get it figured out was going to put it out there so every one could see in case others were interested in going this route.

[LIL QIK]

Hey Jason....

would you mind sharing the list that you ended up needing...and what everything actually ran you? Also...your plans are to do a self install?

[Jason P]

When I get the part numbers with the packing slip I will post them. The in stall depends on overtime. If my work slows I will attempt if not It may go to my buddies shop. Either way I am going to get pictures. I have been working on getting the correct parts for quite awhile, mostly because most parts guys don't have any desire to try and help you. The ones that did help thanks. Maureen @ Rodgers and Kevin @ Parts Taxi.

[MA2010SS]

Hey Jason are you changing out the hubs also? GMPP is selling a complete SS to ZL1 swap starting this spring, I am just waiting on pricing.

http://www.crateenginedepot.com/Cama...94-P50812.aspx

[Jason P]

yes I have zl1 hubs already

[Ken_]

I think there's a lot of things us guys with just your run-of-the-mill SS can do with the stock rear. Changing out the cradle bushings, differential bushings, trailing arm bushings, upgrading the sway bar initially is where I am going to start. Any time you can get the energy going to where it needs to go versus into the realm of slop is a good thing. To each his or her own, I suppose.

Where I am from, getting my hands on a ZL1 rear subframe and all the attaching goodies is probably going to be double what you guys pay.

Not hating, just admiring.

[MA2010SS]

I've already done the differential bushings, billet caps, gears, extra clutches for the posi unit along with gears. My concern is that I have the 6 speed vs the auto. I think the stock rear might hold up ok, but the DS and axles are most likely the weaker links. Spend $900 on a DS, and $1100 on axles and hope the rear can take 1.6 or better 60' times on a stick car consistantly. I've heard that the ZL1 swap might be under 3K for their GMPP direct bolt in kit. If I had an auto I probably wouldn't even think about the differential and just change the DS and axles. Still waiting to see what the pricing is, should be out in a month or so.