crossmember does not fit, need advice

[Little Dicey]

Hello to all. I have been reading many of the threads and wanted to introduce myself and see if anyone can help me out. I have a 1970 C10 chevy pick up that I am putting in a new motor and new TH400 transmission. Since I am going from a manual to an automatic trans I knew I had to change the crossmember. I ordered a tubular one from LMC supposed to be for 1967-1972 Chevy C10. I am at my witts end with this as it seems my chassis frame is 3/4" shorter than the crossmember!! Has anyone encountered this and have a solution as to how to get it to fit? Thanks in advance for any and all suggestions.

PS, My Chevy has been named Lil Dicey.. I will post some pics when I get a little further on.

[franken]

Try fitting the original CM. You might have to move it but trans mounts aren't too different.

[firedemon]

are you switching to an 8 cyl from a six I had to move my motor mounts to the front holes then the trans mount holes lined up with the rear most holes I used the tubular mounts and have a turbo 400 otherwise you will have to drill new holes for the tube trans mount

[Little Dicey]

Originally Posted by franken

Try fitting the original CM. You might have to move it but trans mounts aren't too different.

Let me elaborate a bit. I had to cut out the old CM which was for the old 4 speed manual trans. I needed to install a new one for the Turbo 400. Problem is that the frame width on my truck is 3/4" shorter that the width of the classicperform crossmember.

I just wanted to see if anyone else has had the same problem.

[Little Dicey]

Originally Posted by firedemon

are you switching to an 8 cyl from a six I had to move my motor mounts to the front holes then the trans mount holes lined up with the rear most holes I used the tubular mounts and have a turbo 400 otherwise you will have to drill new holes for the tube trans mount

It already had a 350, I just refreshed the small block that it had, I just changed the transmission to an automatic. I thought the crossmember from LMC would save me some time of fabricating one, but it is too long or I am missing something. Just looking for opinions.

[6T7 C10]

I went from the three speed manual to an automatic and had to cut out the crossmember as well. The new crossmember was pretty tight and a trick to install but not as tight as you indicate. One idea is to use a bottle jack and a spacer of sorts between the rails to see if you can get the frame to spread just enough to fit it in there. Work safe however.

[zicc1835]

interesting i have a frame in the garage I’m restoring im going out to take some measurements and pics for you...stay tuned

[71meangreenc10]

Originally Posted by Little Dicey

Let me elaborate a bit. I had to cut out the old CM which was for the old 4 speed manual trans. I needed to install a new one for the Turbo 400. Problem is that the frame width on my truck is 3/4" shorter that the width of the classicperform crossmember.

I just wanted to see if anyone else has had the same problem.

I had the same issue with a 70 LWB that I converted from a 3spd manual to a 700R4. Ended up cutting the ends off the new crossmember and welded up some square to make it work.

Smitty

[zicc1835]

Originally Posted by zicc1835

interesting i have a frame in the garage I’m restoring im going out to take some measurements and pics for you...stay tuned

inside rail to rail measures between 33 1/4 or 33 3/16 where you see the tape starting to bend its not an exact measure with a tape by myself as you can see but close enough for you to measure yours
then my CM can’t remember who i bought it from ill check my records its snug but i can move it inside the frame rails enough to scratch it as you can see i have just mocked it up i wont drill my holes until i put the cab on to see where my HEI ends up to the firewall but thats my issue not yours
here are some pictures looks like outside demension from rail to rail is approx 34 let me know wht you measure hope this helps

[zicc1835]

one last pic the c-member is approx 33 3/16 end to end i used a couple of clamps to get a better measurement ...and your crossmember measures what ?

[geezer#99]

Even though you’re only mocked up zicc, you realize your tranny yoke is likely too far out of the splines.
Something else to look out for.

[zicc1835]

Originally Posted by geezer#99

Even though you’re only mocked up zicc, you realize your tranny yoke is likely too far out of the splines.
Something else to look out for.

yes sir thanks for noticing in another thread i asked that question .....im not sure if the weigt of the cab including doors loaded and the box on with wood floor will force that inside enough...i bought that shaft from anothe member came out of a inline 6 350 truck you probably know better than i do what those combos measure verses a SB and a 700r4 motor stands in the SB position here are the pics i posted some time ago when i asked that question looks like i need another inch what she said your input will be appreciated no pun intended its getting late
link to post i hope
http://67-72chevytrucks.com/vboard/s...d.php?t=772471

[zicc1835]

just looked at that old post you did give me some good advice its a senior moment for me haha they come mor often now LOL thanks
Jess

[notsolo]

I don't think the weight of the cab etc is going to be enough. Clean up the rest of the yoke and see how far it goes in before it bottoms out. Then pull it out about 1"-1 1/4".

[Little Dicey]

Thanks for all the info. I am excited to go out to the shop and try out some of the ideas. Zicc1835, your pictures are very helpful as they look real close to the ones I took and measurements look the same. I will let you know how it goes later on.

[bs46488]

When I replaced my crossmember the holes were about 1/8 off. I got a 2x4 and cut it a little long so that I could hammer it in like a wedge to spread the frame. Granted I only had to spread my frame 1/8.....3/4 is a much larger gap to compensate for so you might need to do some cutting/welding on the crossmember

[KQQL IT]

Spread the rail with a porta power. These frame are super flexible and move a bunch

[Little Dicey]

Whew!! Thanks to everyone for the advice. Porta Power and a little persuasion from the BFH and 1 beer a few cuss words and it is in!!! Thanks again, now onto making the torque converter match up.

[GASoline71]

Even stock automatic crossmembers have to be installed with a BFH and a block of wood.

Gary