[sherr20]

I am refrencing dimension "D" on page 3-13 underbody of the fisher manual. I just installed my new bowtie overdrives 700r4 crossmember, it took alot of squeezing of the 2 frame rails to get it bolted on, my Dimension "D" is 44 11/16" to 44 13/16" The manual states it should be 44 9/16", Is this within tolerance? It took alot of pressure like I said to get the crossmember in place and held it pushed together under tension, I hope this is ok to be under tension. The subframe is straight other dimensions are within a 1/16" What do you guys think?
Thanks
Jerry

[HwyStarJoe]

Jerry,
I can easily see where that dimension would change over 33 years. Those two mounts can also crack, or crack the frame where they're welded on. An eighth of an inch difference? Sure.
I'll bet the rear mounting points aren't where they were when the car rolled off of the assembly line either. And the way cars were built back then, it very well could have come from the factory that way.

Over years and years of use, I'm sure the frame has changed shape. Every bump strains those points. Did you have to repair the bushing mounting points on the subframe? If not, I'd chalk it up to normal wear and tear. I'm not surprised it took a lot to squeeze it back together either! [img]smile.gif[/img]

[sherr20]

The bushing mounts are fine, round, no rust. What I ended up doing last night was put a ratchet tie down strap around the back end of the frame cinched it down until the holes lined up, bolted the tranny crossmember in, then rechecked the dimension, I am within a 1/16 now, I read more in the manual, 1/16 is the tolerance. Only thing I am concerned with is will the tension I put on the frame rails and then bolted the crossmember in cause problems. The subframe is actually quite flexible, so I am hoping the tension will ease out and the frame will find its "center" again now that it is where it should be, and will be bolted back in, and held in that position.

[HwyStarJoe]

I wouldn't be surpised if it "relaxes" into the shape you have it in now. But you're not far off base by worrying that the tnesion put on the crossmember bolts is kinda scary. The rear subframe mount-to-body bolts will help keep it in place also, so maybe it won't be an issue.

For a lack of any other ideas, you could always enlongate the crossmember holes by 1/32" each towards the inside to help it 'fit' the frame rails better, if you're really concerned.

[sherr20]

I'm not sure yet but if i go to re-mount the subframe and dont have the mount hole dimensions within tolerance I will have to put tension (squeeze together) the frame rails anyway to get the rear body to frame mount to line up. This subframe is a 67 camaro frame but not out of my car. I just thought the dimensions were critical for:
a) to insure it is a straight lined up car
b) to match up with the body mounts when the two pieces are brought together.

I think it will all work out, i was just worried that I'll crack the frame by deflecting inward the frame rail arms over time...we shall see.