ZL1 IRS swap into 2nd gen firebird

[Schroeder]

I have been considering installing an IRS into my 77 trans am. The AME IRS is a total joke for pride point IMO. I have read some on the ZL1 IRS and found that it has a larger gear set and is pretty beefy. Would this be a good candidate for a donor IRS? I know some people use cobra mustang rear ends. Is there any particular year of ZL1 rear I want to look for or avoid? I have done some internet searching and haven't found a lot on this type of project. If someone has seen this done please by all means send me a link.

[Build-It-Break-It]

The link below is a horrible example but it's been done but doesn't seem like an ideal option. It just doesn't fit right and if your going to alter control arms etc you just defeated the purpose of all the engineering that went into it.

http://www.lateral-g.net/forums/show...=47820&page=16

[BonzoHansen]

The AME IRS is a total joke for pride point IMO.

what does that mean?

[Schroeder]

what does that mean?

darn auto correct! I meant the AME IRS is a total joke for PRICE. Not "pride." Haha sorry for the confusion guys.

Build it break it, what do you mean by modifying it and defeating the purpose of all the engineering? I did plan on putting all the DSE 5th gen rear end components on if that's what you mean. I don't think that's a bad thing though. Thanks for the link to the build.

Are there any years to avoid? It seems like I read somewhere that between a couple of the years they beefed up the ZL1 rear end. But I could be dreaming. Maybe I'm just thinking of the difference between the SS and the ZL1.

[dhutton]

I meant the AME IRS is a total joke for PRICE.

Let's hope you're still laughing when you're done and Mary Pozzi kicks your butt with her Art Morrison IRS... LOL...

Don

[Randy67]

Chevy offers the ZL1 HD driveline kit to upgrade the SS cars. So you don't necessarily need to find a ZL1, you can start with the rear suspension from a 2010-15 Camaro SS and add the ZL1 kit, more on the kit here: http://www.chevrolet.com/performance...s/1le-zl1.html As a side note, you can find the kit cheaper online, just search the GM part number. Sometimes you can find used ZL1 center sections, which could save a few $$$.

[Schroeder]

Thanks a lot, Randy. What are some of the thoughts floating around on his? I can't believe this hasn't been done many times over already. Is there something that I don't know about that makes using this setup in a 2nd gen more trouble than it's worth? In the thread on their IRS AME said 2nd gens needed to use the compact version of their setup. Maybe the ZL1 setup simply doesn't fit in a 2nd gen? AME posted reference dimension drawings that showed the difference between their different layouts for their IRS. Does anyone have something like this for the ZL1 IRS or know who I could contact that may have access to it? Maybe DSE would have his information since they have a parts line for this IRS???

Chevy offers the ZL1 HD driveline kit to upgrade the SS cars. So you don't necessarily need to find a ZL1, you can start with the rear suspension from a 2010-15 Camaro SS and add the ZL1 kit, more on the kit here: http://www.chevrolet.com/performance...s/1le-zl1.html As a side note, you can find the kit cheaper online, just search the GM part number. Sometimes you can find used ZL1 center sections, which could save a few $$$.

[dhutton]

Did you go through the thread listed above to see how much headache it was to put a 5th gen IRS in a second gen car? Somewhere in the thread he admits he should have used the Art Morrison IRS....

Don

[Schroeder]

I have been through the thread. I need to go trough it again though. I was subscribed to Grendel's thread before it was posted here. I totally forgot he used the zl1 IRS though. I need to review the whole thing. I thought most of the IRS woes were due to incompetency by the first show that had the car. Again, I need to review and could be wrong. They're both hack and fan units. I wonder why 1 is worse than the other

[F-Body International]

I was getting ready to sell my setup to buy a late IRS rear end like this for my '79 but what held me back was the different bolt patterns for the wheels. 5th gen F-Body IRS uses a metric bolt pattern for the wheels. I'm going for a 3rd gen Firehawk wheel on mine that uses standard 5x4.75 bolt pattern like early cars. Leaf springs it is for me!

[dhutton]

I was getting ready to sell my setup to buy a late IRS rear end like this for my '79 but what held me back was the different bolt patterns for the wheels. 5th gen F-Body IRS uses a metric bolt pattern for the wheels. I'm going for a 3rd gen Firehawk wheel on mine that uses standard 5x4.75 bolt pattern like early cars. Leaf springs it is for me!

You can swap out the hubs for Corvette hubs....

Don

[Protour_Pinto]

I was getting ready to sell my setup to buy a late IRS rear end like this for my '79 but what held me back was the different bolt patterns for the wheels. 5th gen F-Body IRS uses a metric bolt pattern for the wheels. I'm going for a 3rd gen Firehawk wheel on mine that uses standard 5x4.75 bolt pattern like early cars. Leaf springs it is for me!

You can have the hubs redrilled for the pattern you want.

I redrilled mine from the Caddy pattern to the Ford pattern.

[andrewb70]

I think the main issue is track width. The 5th gen is much wider than the stock rear end, and when you try to narrow it, the geometry gets messed up.

Andrew

[Schroeder]

What is the width of the ZL1 rear from WMS to WMS? The stock 2nd gens are 56" aren't they?



Pro touring pinto, have you pu a ZL1 IRS in a car too then?

[andrewb70]

What is the width of the ZL1 rear from WMS to WMS? The stock 2nd gens are 56" aren't they?

Pro touring pinto, have you pu a ZL1 IRS in a car too then?

Rear track for 2010 SS is 63.7"

Andrew

[Protour_Pinto]

Pro touring pinto, have you pu a ZL1 IRS in a car too then?

Nope, Just a Eldo drivetrain in the back of a Toyota pickup, A Jag in a pinto

The OP mentioned the different bolt pattern was an issue.