Installed BBK LT's in a buddies 03.

[Silver 03 Cobra]

I installed a set of BBK LT's and BBK o/r h-pipe on my buddies 03 this Saturday. I had a little help and with the k-member off it took 8 hours. I installed a set on my 01 so I was prepared for an easy install. But, I ran into a small problem. The top back 3 bolts/studs on the passenger side were a pain. I had the same problem with the JBA's I put on my 03 only it was the top back two. The problem is you can't lower the engine far enough to clear the frame rail. I didn't have this problem on my 01 because I could lower it a lot more than the 03. other than that it went very well.

We hope to dyno tomorrow and compare the numbers to what I got after the header install with minor differences. I have a dyno sheet with JBA 1 5/8 Cat4Ward headers, Bassani o/r x-pipe and catback, K&N air filter in the stock air box. I also have 4.10's. My numbers were 411/384 SAE. My buddy will have the BBK LT headers, BBK o/r h-pipe and Flowmaster catback with the stock gears. I'm going to put my K&N air filter in his car. This should be a pretty good head to head comparo. I think my 4.10's probably pulled 5 rwhp off my numbers. I'm not sure what the difference between the Flowmaster and Bassani catbacks is. I'll post the numbers when we get them.

He'll have to have gonzo big numbers over mine before I'll pull the JBA's off mine. I've done two header installs and a 4.10 gear install on my 03 and my buddies on 3 out of the last 4 Saturdays. I'm ready for a break.

 

[Snakebitten]

Cool, I'm lookin' at the same BBK set up.

 

[Silver 03 Cobra]

My buddy just emailed me and told me he wants to get JDM's cool air filter before he dynos. Probably will be a few days. I think I want to dyno it more than he does.

 

[f4sfed]

How hard was the rear gear change? Anything special needed? Was it easier or harder being IRS?

That was the first thing I changed on my '97 Cobra, and MAN what difference!

Thanks!
FF

 

[Silver 03 Cobra]

I've never did a gear swap on a solid axle but I've read the steps. The toughest work on an IRS is to get the differential out of the IRS. You can't change the gear while it is in the car. The easy part compared to a solid axle is you can change the gear out while it's sitting on a work bench.

If you go over to Corral.net in the DOHC forum, search for Lynch. Joe Lynch has some great instructions with pics on how to get the differential out. Find his website in his sig. Then in the tech section on Corral, find their 8.8 gear swap. It is for an 8.8 solid axle but the gear change is exactly the same as the 99-03 Cobras. The IRS differential uses the same ring/pinion gears, bearings, seals etc. You will need some specialized tools. If you have a pretty good mechanical ability, it's not that hard. The toughest part is setting the backlash. Order a shim kit from Summit and new pinion bearings from Autozone. Don't even bother trying to remove the pinion bearing from your stock pinion gear. Put a .030" thick pinion shim under your inner pinion bearing and 9 out of 10 times your backlash will be in spec.

A lot of people pull the differential themselves to save money and then take the differential to a good gear shop. I could change gears all day that way. The toughest part and time consuming is getting it out. Let me know if you need any help and I can lay out a few steps. I've done 4 IRS Cobras and I'll probably do my buddies soon. I know people said I made a mistake putting 4.10's in but they are wrong. That is the best mod I've done so far. It compliments the 450 rwhp in my opinion.

I will be willing to bet when they run the 03's up in BG, KY that most of the top spots will go to people running 4.10's or lower. Watch.

 

[f4sfed]

Cool! Thanks!

 

[Silver 03 Cobra]

I talked to my buddy today and his JDM filter will be here by Friday. We are going to dyno his 03 next Wednesday. I'll post the BBK vs. JBA dyno sheets that day.