RE throttle springs: For safety sake run an additional spring from the carburetor throttle arm to some convenient place that doesn't get real hot i.e. NOT the exhaust manifold studs. That way if the linkage clip breaks or a cotter pin falls out the throttle will close. If left to their own devices many a throttle will default to wide open. This is not good.
If you think mine are run to manifold studs , you are quite wrong. Oil pan
