I got a brand new 26" aluminum radiator for my 68 B body big block. It's a US radiator/ Coolcraft that is a direct replacement. Looks beautiful, nice quality, proper anchors, shroud fits right on. All great, except the lower tank is much bigger and it hits the lower tie bar and the holes are 1 1/4" from lining up. If it could drop down 1 1/4" it would bolt right in. I think the lower tank is the issue. I've called the manufacturer and they are being helpful. I hate to cut or modify the lower tie bar.
Has anyone else ran into this with their radiators?

Help me out here, a more detailed description of the "tie bar" is?

Gotta be talking about the brake strut that ties the lower control arm into the front end, under the radiator.
I have the smaller radiator in a 68 big block B body and there is tons of room down there. In no way do you want to fool with any links or bars to make that fit.
Do you have a picture so we can have a look at the issues?

I would just get one that fits. I know many who have installed these (26") with little or no trouble.

http://www.championradiators.com/page/400655622

I put one in mine, but I had to drill new mount holes because mine originally came with a 22" radiator. Otherwise it fit fine.

Yes: And if you were to drop the mounting points then your rad cap would hit the hood. I've experienced this myself. Does it have a trans cooler? If it doesn't maybe find a factory C-body rad to steal the lower tank from, but if the core isn't stock height your'e out of luck no matter what.

Sheldon