Billet Manifold for Blue Thunder M/R Head

DON BEVERS · #1 (**permalink**) 09-21-2008, 03:05 PM

We have completed our billet manifold for the Blue Thunder medium riser head. This manifold accepts TWM and Weber carbs. Motor goes in this week and we are using the TWM EFI individual runner setup.
Pictures attached. We are excited!

rokndad · #2 (**permalink**) 09-21-2008, 05:39 PM

Nice piece of engineering. Let us know how the install on the TWM's go. I know Rodknock is interested in this as well. How lumpy is the cam you're using....specs?

DON BEVERS · #3 (**permalink**) 09-22-2008, 08:03 AM

Thanks. It was definately alot of work and computer time. The cam, a hydraulic roller, was designed with cruising in mind. It needed to be free of radical behavior by about 2000 rpm. As such, the overlap is only 14 degrees. Duration @.050 232 int & 244 exh. w/lift numbers just over .600 in for both. The head flow reaches 300cfm by .500 in. and we only flowed them to .6 because of the cam being used. Lobe separation to achieve the short overlap is 112. We design our own cams using profiles from Comp with help from long time contact/friends. The short overlap was felt to be needed with an I.R. type of intake system to try and fend off regurgitation and fuel stand-off which is generated when both valves are open at the same time. The EFI probably handles most of that, but smooth and power were the objectives here.