I've been in this forum for months, and havent seen anyone mention it. I did the search.

Fmax has expansion slots on their flange. I used to think they had the best casted manifold out there.
There might be some sense in having expansion slots on the flange. Less chance of getting leaks. Also there might be evidence that a one-piece flange causes head warpage.

 

I thought f max was welded not cast? are you refering to the cuts through the head flange?

 

My F-Max mani is a series of thickass tubing welded together. Seems like a great was to mass product hgihly streetable, non crack prone manifolds to me

I my F-Max manifold, although it may be costing me 10-20 HP over an Inline Pro or something similar. I also love the wasy it HUGS the block for my tiny li'l engine bay'ed ED

 

The expansion slots work great. I think the Max-rev does this, but Im not sure.

 

yeah the maxrev mani's got expansion slots

 

Picture?

 

These were taken during the install





You can see the slots in the manifold to head flange between #1 and #2 cyl and #3 and #4 as well.

 

It allows the manifold to expand more uniformly when heated, so it does not crack as easily.