I have a 68 chevelle that had a th350 and now it has a th400. I just installed hedmen longtube headers and im having trouble trying to figure out how to route my exhaust system with my crossmember in the way. Maybe I have the wrong crossmember, does anyone have any pictures of an exhuast system from the bottom? Thanks in advance-

is all else fails thy here. http://www.lemonsheaders.com/ go to the product list, then to crossmember. what i had to do. HTH, Dave

1968Rat, you have mail

Like heavy duty, trick stuff? Check out these guys, with a new GM A-body crossmember product: http://www.geocities.com/gforcejohn/

I'm using one on my Pro Touring '71 Chevelle. Nice & strong, plenty of room for HUGE exhaust system.

Thanks guys for the replies. Undee, the pic didnt want to decompress correctly; it says its a corrupted file. I think the question I should be asking is if my crossmember was installed correctly. On the inside of the frame there is the opening where the crossmember is bolted in. Being that I went from a th350 to a th400 the shop insisted that the crossmember be mounted on the bottom of the frame as opposed to mounting it in the frame. What I mean by in is that if nothing was holding the crossmember, it would sit on the inside of the frame. They put it below the frame and used a half inch spacer and bolted it in becuase the 400 needed more clearance. Does this sound about right?

I just did that swap...350 to 400, my exhaust with a H pipe was fine,didnt have to move anything,except the crossmember towards the rear,and my crossmember is in the frame,not below it. I am using dynomax 1.75 tube headers and 3" pipes with dumps at the rearend. No pics though, sorry.

Originally posted by 1968Rat:
They put it below the frame and used a half inch spacer and bolted it in becuase the 400 needed more clearance. Does this sound about right? You may have the wrong crossmember. Th350s and TH400s I believe used a different crossmember. It also should sit inside the frame. I resent the pics

Cross member for the 400 / 350 are one in the same, it should just slide back inside the frame rails, and should line up with existing factory holes in the frame rails. Fixing to finnish up my 350 to 400 swap, have to pull the headers one more time after test fitting the scavenger collectors. Mounting the cross member below the rails with spacers is not normal for a correct stock crossmember.

could there be a problem with the motor mount perches?

i took some photos of my situation maybe you guys can check it out and help me in the right direction. Ill send it to whomever, just let me know, thanks

I would like to see the photo's. I have my crossmember off of the car right now, would like to compare.

Sounds like wrong crossmember to me. Send me the pics or post them on something like www.webshots.com (http://www.webshots.com) for free and link them.
As said already crossmember should be in the frame.

I'm using the same crossmember that was under my 350,just slid it back a few inches. graemlins/thumbsup.gif

Just thought others might be interested in this story... Some years back, I put a highly modified trans in my velle. It's a twin turbo 400. Doing so meant many modifications, not the least of which was relocating the trans crossmember back quite a distance from stock. During the initial stages of wringing it out, I had that trans in and out many times. I thought about wing nuts at one point ;) Anyway, it was a real pain to get the trans out and the crossmember would just get wedged insode the frame rails. The whole shebang had to come out together. After much hand wringing over whether or not the thing woudl survive, I mounted the cross member under the frame rails. I have appropriate load distribution mechanisms (i.e. custom washers) to insure it isn't just the bolt heads taking all the load and distributing it onto the rails. Long story short- it's been that way for more than 5 years, taken innumerable hard launches on both the street and strip and not a bit of trouble with the mounting scheme. No distortion, cracking or other signs of stress on the frame rails. And it's so easy to get that trans out now that I almost want to do it again just for the fun of it (not!). Anyway, since I worried over it for so long before resorting to it, thought you might benefit as well...

disclaimer: YMMV

JYD71..........I have got to ask! What is a twin turbo 400? Some kind of one off custom 6 speed super trans? Inquiring minds want to know. :eek:

It's two TH400 in series. The front trans has only the forward gear set, pump and torque converter but no tailshaft. The rear trans has the full complement of gears, no bellhousing pump or converter. A custom shaft interfaces the output of the front trans to the input of the rear with a plate that connects the two together.

The front trans has a shallow pan, the rear a deep one. Each pan has a short length of 3" tubing welded into it (the front comes out the bottom and bends toward the rear, the rear pan has the tube extend straight forward out the front edge). The two are connected with a piece of hydraulic hose. The front trans sumps from the rear using PVC tubing that snakes through the inside of the aforementioned pan connections. A high pressure hose makes the pressure connection between the two through the drilled and tapped side ports. I'm running significantly higher line pressure which yields some pretty impressive positive shifting.

There are many ways you could set up the shifting, I chose to set it up as independant, reverse ordered, manual valve bodies. I use two B&M quick silver ratcheting shifters.

The result is a rock solid transmission with 5 forward speeds (2 reverse smile.gif ). The tradeoff is a slight weight penalty, if I recall correctly, about 80 lbs. I'm running 2.73 rears. I can drive to the strip on the freeway and still launch the car impressively at the track (or pull stumps from your backyard ;) )

I've seen the same setup in a blown BBC putting out nearly 1000hp. Aside from breaking a hub once, the thing has performed better than I ever expected. And, it kinda sets my ride aside from others at cruise nights (what's with that "extra" shifter?)

I have pictures but haven't kept up with my old web page so doubt they would still be available. I'll see what I can do about posting them so you can see what I'm trying to describe...

Originally posted by JYD71_454:


I have pictures but haven't kept up with my old web page so doubt they would still be available. I'll see what I can do about posting them so you can see what I'm trying to describe... Post some pics, would really like to see how it all fitted in

If ya know how to weld you can just cut a chunk or two out of the crossmember and box it back in. I did this with my Nova's alternator, I wanted the low mount so I built the mount how I liked it before I put the motor in, then when I put the motor/alternator in and it didnt work I just cut a chunk outta the frame crossmember about an 1" deep by 5" long and boxed it in. Now its way sexy. You might be able to get a better looking exhaust this way too!