I just finished porting & polishing a set of GM 601 heads for a carbureted 305 in my third gen. Does anyone have experience with blocking off the exhaust crossovers. I have no emmission items on this engine but it is a daily driver during fair wx here in the midwest.
Any info pro or con would be greatly appreciated.

Thanks,

Roy

 

For a nice weather car, I would always block off the crossover. It's there to help heat up the carb faster during cold weather. In the summer, it isn't needed, plus it also makes the carb run hotter.

 

Thanks, Nice dual quads on top that tunnel ram! I will block them off. My Fel Pro 1205 gaskets do not have the cross over hole. I fabricated a .010" thick peice of aluminum extending 1/2" beyond each center intake bolt hole matching the head shape and drilled holes for the intake bolts. I plan on placing these on the head w/gasgacinch and covering w/ the 1205 intake gaskets. I do not believe this will interfere with the sealing of the intake to the heads.

Thanks again,
Roy

 

If your intake gaskets don't have the crossover openings, why are you making the aluminum cover plates? The gasket is already going to seal off the ports. And unless you embed those aluminum pieces into the gasket, you take a chance of creating an intake manifold fitment/sealing issue. I wouldn't bother with doing any of that myself.

 

Thanks 69Camaro, if the .010 aluminum is not needed and the Fel-pro 1205 gasket material is sufficient it makes it all the easier.
Thanks,
Roy