The original max wedge intake doesn't use a valley cover, the intake manifold does that. As far as trying to use a set of 240 heads that will make a lot of reversion with a stock M.W. intake due to the M.W. heads intake ports are taller and flow more air than the standard 361 up to the stock 440 heads, it will cause flow reversion at the head surfaces, not GOOD
I've never bought or used a set of the 270 heads yet. If they have the same size intake ports as the original M.W. heads had the stock intake should work okay
I've owned and race a bunch of cars with max wedge motors and love them
There are better parts available now so if you want more power than those early M.W. motors made buy newer better parts like Indy 440-1 heads and a custom sheet metal cross ram intake
IHTHs