I have used the Edelbrock Varajection setup, and while I cannot really blame Edelbrock for the trouble I had, I ended up taking it off pretty quickly. You need to use only distilled water in the system, and if you don't the small passages will fill up with corrosion quickly. It was a pain in the neck. I ended up rebuilding the engine and installing TRW L2240NF pistons. These pistons have extra material in the dome area so that they can be custom machined. I had them machined to remove most of the dome. This solved the problem permanently. My engine is a 396, I think that the 427 equivalent piston is the 2300NF. For some reason when I search for these numbers now I get Speed Pro numbers as often as I get TRW. Maybe they are the same company now?
Here are some web sites with information.
http://www.federal-mogul.com/speedpr...speed_pro.html
http://www.flatlanderracing.com/trwchevy396_427.html