Any advantage in using 73-87 front crossmember?
 

Planning on swapping the front suspension on a 1972 C20 8-lug truck to suspension off a 1974 C10 5-lug truck. I have the complete suspension crossmember and all off the 74 C10. I just don't know if there is really any advantages in swapping out the crossmembers when doing this seap. The only thing I have found is the low a-arm shaft retainer u-bolts are bigger on the 74 crossmember. But is there anything else? Are the larger retainer u-bolts really that much better when the truck is just going to be a daily driver?

Would I be smarter to just swap over the 74 suspension components onto the 72 crossmember. Or it really is smarter to swap over everthing, crossmember included. Looking all the advice I can get on this. Thanks.

Re: Any advantage in using 73-87 front crossmember?
 

I think in 72 the C20 would have had 8 lugs so wondering what you have. Perhaps 4 wheel drive 1/2 ton?

Re: Any advantage in using 73-87 front crossmember?
 

Sorry, both 1972 C20 I am building, and the 1974 donor suspension are off 2wd trucks.

And you are correct. The 1972 C20 is 8 lug, I keep mistakenly put 6-lug.

Re: Any advantage in using 73-87 front crossmember?
 

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You will get differing opinions but I have always swapped the complete x-member. The one deciding factor for me is that all of the ones I have swapped into did not have engines in them.
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Re: Any advantage in using 73-87 front crossmember?
 

When I swapped mine the engine was in place. That had no affect on my decision, I don't really see the correlation. Explain your reasoning please?

Re: Any advantage in using 73-87 front crossmember?
 

Have you considered doing the caster mod while your doing the work?

http://67-72chevytrucks.com/vboard/s...d.php?t=501241

Re: Any advantage in using 73-87 front crossmember?
 

I did this exact same thing in my 69,I put the whole c=member in mine but I had help they are clumsy to do by yourself. All you really need are the a-arms enlarge a couple holes t week your brake lines and your good to go. Keep in mind I had no engine/trans in either 1 of mine at the time I did my swap.This is a good time to re-do all your ball joints,bushings etc.

Re: Any advantage in using 73-87 front crossmember?
 

I have been debating on doing that while we have the arms apart replacing bushings. Can you explain/remind me the advantages of doing this?

Re: Any advantage in using 73-87 front crossmember?
 

The factory suspension doesn't allow for much more than 1 or 2 degrees of caster. 1 or 2 degrees is what old straight axle trucks had. This small amount of caster is what makes it easier to turn the steering wheel when the truck is not moving. This is nice when you don't have power steering but, the down side is when turning at speed the steering doesn't return to center on its own and the truck has a tendency to wander on the highway.

When you have more caster (5 to 7 degrees) the steering will now return to center naturally after a turn and the truck will seem more composed going down the highway now your not chasing it all the time. New cars can have as much as 12-14 degrees of caster but that much is not needed for our trucks.

The only downside for our trucks I am aware of is that when I did mine, with the air bags, and the relocated upper shock mounts, I needed to modify my lower shock mounts. I don't think folks with a more stock set up have had to do that.

I believe its a pretty common modification and best of all if you do the new index hole 180 degrees on the shaft from the factory index hole if you don't like it you can just loosen the shaft and reposition the shaft back in the factory index hole.

From what I have read here it appears that some of the replacement shafts now available have moved the index hole to allow a bit more caster than the factory shafts did.

Re: Any advantage in using 73-87 front crossmember?
 

Oh that make sense. Didn't do that mod on the 69 burban we built (ran out of time) and she likes to dance a little going down the road. Maybe this mod woupd have helped with that. Sounds like we will be doing it this time around to see how much of a difference there is.

Re: Any advantage in using 73-87 front crossmember?
 

Sure. The main thing for me is trying to get the frame jacked up and the engine blocked up. I have limited space in my shop (my fault) and I don't have any help local to me. It has just worked out that every truck I wanted to put front disks on did not have an engine in it.... So I just changed the whole X-member. I didn't mean to imply that that was the best way to do it, just the way I have done it in the past.

Re: Any advantage in using 73-87 front crossmember?
 

And at least 15 year newer metal.
They can crack