Here are a few pics of some different cooling solutions that we've run across. One is low-buck, the other is on the pricey side, but both are sure to spark an idea or two for your own project.

The radiator in the first few are from a Ford 4x4 truck. The application doesn't matter, it's that you can use any radiator that will physically fit, if you don't mind a little work, and have the tools. You're not limited to Chrysler rads or the expensive aftermarket ones. Just head out to the junk yard with over-all dimensions of your support, and pick the biggest one that'll fit the area. Mounts can be made quite easily. Just hold the rad in place, and make some plates that will bolt to the support. Tack these plates to the rad frame, drill your holes and you're done. Hoses come in a million shapes and trans lines can be bent to go anywhere. This radiator was $173 new at the local parts store. A bit cheaper than the aftermarket aluminum ones. ....unless of course, you're going to make 600 or 700 horsepower...thats enough to need a GOOD radiator.

One other note...The most horsepower will be made with a thermal clutch fan or an electric. The fixed fans like I have are cheap and look neat, but 5 or 10 horsepower is worth the cost of a thermal clutch or electric. I'll be switching to one soon myself. Also, fan clearance should be 1 - 2" without a shroud, and with a shroud, the fan should be half in and half out.

The fan clearance worked out perfect in this install. That's a stock 2" spacer in there and this is the Ford truck rad.

 

Here you can see the flat plates tacked to the rad frame to mount it. It is a down-flow so the trans fittings line up nice too.

Here's a more advanced installation. A Howe 19x28 alum. rad is used along with a Meziere electric pump. The rad hoses were a close match to this combo. The lower fit directly and is PN#(E)70859 from most local parts stores. The upper required trimming both ends and is PN#(C)70780.

The cheaper aftermarket rads don't come with mounting provisions, but its as simple as TIG  or MIG welding these L brackets on. Not much work to save yourself $300 or so dollars.