Manifolds are available that have the standard 289 thermostat housing, but none of the manifolds I've seen (European or American) include provision for the PCV valve or a vacuum takeoff for a brake booster. So, street mods are required.

A "log" can be fabricated out of aluminum and located underneath the intake manifold (out of sight) with 1/4" runners to each manifold port to provide vacuum from all 8 cylinders. These runners are on the bottom of the log. The upper part of the log (next to the bottom of the intake) is separated from the lower part by a baffle. At the rear of the manifold an external port is connected to the top half of the log for vacuum to the brake booster. A second port connects to the lower half of the log for the PCV connection. The two ports will have to be located such that they (and hoses, clamps) don't interfere with the throttle linkage.

Air cleaners are also a problem. These Webers use velocity stacks and extended auxilliary venturis to contain mixture rejection (pressure back through the carb during intake/exhaust valve opening overlap). Further, they're designed to be used WITHOUT air filters. So, a look at what's on the market (K&N, European "Lynx") and your hood clearance is in order. The Weber velocity stack should clear the air cleaner by at least 3/8" (preferably more than 3/8"). You may wind up customizing existing air filters or making your own housings.

A high quality fuel filter should be part of the installation. Finally, Webers do not tolerate high fuel pressure, so a pressure regulator (or an electric pump with built in regulation) that delivers 4 psi max is in order.

All things considered, it would be easier to install a Paxton supercharger, and the blower would make more power.

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Alex Denysenko Co-Administrator and Moderator