For the HEI, please avoid the ones made in China (sometimes called the big ugly blue ones or big ugly red ones). They will work but the one I have has developed a bad habit of drawing oil up the shaft and depositing it in the dist body (where it eventually pours out the cap). A Performance sells them along with several other sellers on eBay, Amazon, elsewhere. Look at the reviews on Amazon. Seems many had the oil problem.
The one I bought from Tom Langdon is a much better product and replacement parts are available at auto parts stores.