Manual trans cross member - same position 6 vs 8?

[ScottH]

I have a 72 Cheyenne I recently pulled stock 6cyl engine with 3 speed trans out of. I plan to install a 350 with the original trans. I know the 8 engine mounts have to be changed and moved forward, but what about the trans cross member? Will it still bolt up to bellhousing in the original 6 cyl position?

I tried doing a search but could not find anything definitive on 6 vs 8 manual trans crossmember position.

Any info is appreciated.

Thanks
Scott

[wreckedchevy]

apparently I did mine wrong I just used the 6's stands and ended using a BFH to fix the distributer clearance, where was the forum's 20 years ago :-)

[Lattimer]

My small block sits in the L-6 position. Fits fine, distributor is close to the firewall but not too bad. If you are keeping the original trans, I'd keep the 6 cyl mounts so you don't need to swap the driveshaft.

[wreckedchevy]

only other thing I've noticed is the clutch linkage is really close to the manifold I put over 200,000 miles on my truck like this with no issues but it's really close like you can't get a piece of paper in between close I might have something else wrong but not sure what. I have 4 on the floor instead of 3 speed.


pic isn't the best angle but only one I got

[ScottH]

So if I install the 350 in the stock 8 position, will the bellhousing mounts line up with 6 cyl cross member?

[Lattimer]

Originally Posted by ScottH

So if I install the 350 in the stock 8 position, will the bellhousing mounts line up with 6 cyl cross member?

No, you have to move the crossmember forward if you are going to use it. The V-8 position is a couple inches forward of the L-6. From looking at it, I think you will have to lift the cab to get the rivets out of the crossmember.

The distance from front mount to bellhousing mount is the same between the 250 L-6 and the small block V-8. I understand the 292 has different mounts but I have no experience with them.

If you use the V-8 mounting position the end of your trans will move forward and you will need a longer driveshaft.

[Lattimer]

Originally Posted by wreckedchevy

only other thing I've noticed is the clutch linkage is really close to the manifold I put over 200,000 miles on my truck like this with no issues but it's really close like you can't get a piece of paper in between close I might have something else wrong but not sure what. I have 4 on the floor instead of 3 speed.

Attachment 1135088
pic isn't the best angle but only one I got

I have long tube headers, which gives me a lot more room there.

[ScottH]

Thanks guys for the info.

One more question, if I leave the 350 engine mounts in the 6 cyl position, should I use 6 cyl engine stands or 8 cyl engine stands?

[67_C-30]

Originally Posted by ScottH

Thanks guys for the info.

One more question, if I leave the 350 engine mounts in the 6 cyl position, should I use 6 cyl engine stands or 8 cyl engine stands?

I <think> the 6 and 8 mounts are the same, just bolt in a different location, IIRC.

[wreckedchevy]

I read somewhere that the 8 stands are a little different and move the motor forward 1" if you use them in the 6 cyl position. I had them available but didn't think they were different so I just used the 6 cyl stand's and no real issues just had to tap on the firewall to make a little bit more room for the HEI distributor, can't even tell with the motor in that I did it.

[Lattimer]

Not sure on mine, but I have enough room for the dizzy without any firewall mods, so I might have V-8 stands.

[allons]

tx firefighter is the man that knows all about the location and hardware for such mods. He helped me immensely when I changed from a L6 3 speed to a V8 speed. Contact him!

[allons]

You can use the L6 stands in the L6 position with a V8 and it mounts up nicely, close, but nicely. The bell housing for the L6 is the same as the V8 and will mount into the existing Xmember. Again, check with tx firefighter, but I think that is correct!

[WIDESIDE72]

You dont HAVE to pull the cab to remove the 6 cyl rear crossmember, but it is easier. I have seen swps were they took a torch to it and just cut what was needed for the auto trans to clear. Iirc, the 6 cyl 3 spd trans did jot use a trans cross member.
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[Tx Firefighter]

Six cylinder and small block mounts are much different. You cannot bolt them in the wrong holes. That is, you cannot bolt the small block mounts into the six cylinder mount holes. Notice on your frame rails, there are three holes per side. The six mounts use the rear two holes, the small block and big block, the front two holes. There are more corresponding holes in the lower crossmember to receive the mount too. They are in all trucks for all different applications. No drilling is required if you use the right parts. I am not speaking of 292 six mounts though as the passenger side one on that engine is a queer deal and not relevant here.

[ALA]

Do you have a v8 bell housing crossmember sra@aacyclesports.com

[scott-wisc]

You will need a x-member from a V8 truck. You do not have to lift the cab to get the old one out. I used the 390 H.P. GM Crate Motor, no complaints.

[scott-wisc]

Correction; 290 horse.

[Craftsmen]

Hi Scott-Wisc, when you removed the six cyl. Crossmember did you have to cut it up to get the rivets out? Destroying it? Thanks Rick

[scott-wisc]

I removed all the rivets that connected the x-member to the frame and the ones that connected the three pieces of the member itself. Before installing the replacement, I dismantled it, reassembled it in the frame and bolted it back together with grade 5 bolts. To get the rivets out, I ground the heads off with a 4 1/2 angle grinder and punched them out.