Originally posted by Dallas4u
The coolant hoses that run into and out of the top of the intake manifold circulate coolant through the manifold for warm cold-engine starts. It heat up the manifold (circulating warm coolant through it) so the engine starts better on cold days... if you live in a wamrer climate you may consider bypassing the manifold by just taking both hoses off the top and adding a "barb" or fitting in between (joining both hoses together). Some say you can gain a little horsepower this way... I think I feel a difference, maybe not.

The crank case expels a little gas back into the intake, which goes back into the manifold and engine. Adding a filter keeps the gasses from going back in... whether it helps of hinders, I don't know. You'll hear both sides, but I think many agree it is just cleaner.
I might try the bypassing of the coolant, I'll talk it over with my shop guy...it's waaaay to hot here and that might help.

Thanks- Jay