Hey guys,

My Bird has seen 300 miles of road/track time since I installed the 6.0L/TH400. Well after filling up at each passing gas station, I've decided to have a 4L60E built up to replace the TH400 and its 10mpg's! I have a Spohn Torque arm and crossmember combo on the car at the moment as well as a non y-pipe friendly set of 3" Hawks/Stainless Works long tube headers on the car.

Anyways, I ran into problems routing an exhaust around the Spohn's bulky crossmember. I only ran 3" Flex pipe but I did have to cut into the crossmember because it was nearly impossible to route around it. I can get pictures of what I'm talking about if needed.

Well, now's the time to decide whether or not I want to buy the 4L60E Spohn Crossmember or have one fabricated. I just want some advice or guidance on what other people have ran into when fabricating their 3" y-pipe. Pics are always helpful!

Thanks,
Chris

 

with 3.23 gears that can't be the reason your mileage is that bad, go get a dyno tune on it with a wideband IMO. That gear ratio is no different than a 4th gen with overdrive and 3.73s

 

Well it has been dyno tuned, needs some polishing on the tune. But it does have ported heads, a big cam, and a fast 92 intake.... I'm not asking why I should keep my th400, I need advice on exhaust and crossmembers lol

 

if you already have the spohn torque arm, i would think it would be cheaper to just buy the crossmember and cut it ( I did the same thing). Not sure you could fab that for less than the 150 they charge, and its coated already. guess it depends on if you are fabbing and if your time is worth it to you or not.

another note, if you're in a fabbing mood, maybe you should be thinking 4l80e, as they have to be fabricated to begin with.


also that must be some cam, my 98 ls1 w/ a gt2 cam and 3k stall th400 made 18 city when I took it easy. =D

 

Build a new crossmember and sell the TH400 unit

Should nearly break even on the swap

 

That's what I'm hoping. Yeah, I know my tune is pretty off but I want the overdrive! I am having the local fabricator take a look at it!

 

Also a "big cam" won't like low load low rpm driving in overdrive without some surging I'm guessing as well.

 

Its not a huge cam, its a 235/242 cam with .621/.624 lift. I think it'll be fine with proper tuning.

 

Damn what's huge to you then?? lol