Some low lift heads with smaller cylinders and smaller valves and the PORT SHAPE have more flow than a high lift rocker ratio or camshaft.
This is a trick we use up here in the NASCAR 1/3 mile track in Palmer. They have a lift limitation with stipulations on STOCK camshafts and STOCK heads with STOCK intakes. Anything goes for the exhaust, but you are limited to maximum of 4 barrel carburetor NO FUEL INJECTION, and must have a distributor.
So with lift limitations, the small valve 350 heads, (cheap) and the 305 block (cheap) and a dual plane manifold and the carburetor set up for max airflow, the gaskets trimmed, the ports have the castings painted/ filled (not allowed to grind/ port-polish...) for smooth airflow, the back of the valve is polished, and the spark plug is selected on heat range and how close they can get to the top of the piston with reach.
This, all coupled with an ALMOST free-flow exhaust (required to have a resonator/ silencer- look up Michelle Church and 'Friends of Mat-Su' for noise over this....) with aerodynamics to create drag on the back of the car and the position of the tailpipe to 'suck' the exhaust out...
This all makes for a very high torque low lift valve system on an engine that wins championships.
In which context did I mention a device for improving vacuum. After a bazillion posts...I might need a refresher to remind me on which device/ technology it may be.
I have seen too much.......
AlaskaStarStatistics: Posted by AlaskaStar — Tue Dec 02, 2008 1:40 am
]]>