Tips on filling Exhaust Crossover

[Tom Goldman]

The cyl head section in the rule book reads ,"heat riser passage may be blocked from the intake manifold of the cylinder head .
Blocking the passage down in the valve pocket prohibited"
As long as the filler is recessed from the pocket ,it's legal.
You wont find a spec anywhere ,but I've seen Record holding heads that the filler is recessed about 3/8 of an inch.

[dartman]

Originally Posted by Tom Goldman

The cyl head section in the rule book reads ,"heat riser passage may be blocked from the intake manifold of the cylinder head .
Blocking the passage down in the valve pocket prohibited"
As long as the filler is recessed from the pocket ,it's legal.
You wont find a spec anywhere ,but I've seen Record holding heads that the filler is recessed about 3/8 of an inch.

does anybody have that in " notified of approval in writing from NHRA" on how far recessed it must be ? as stated in the section "how to use this RULEBOOK" on page XVII of the 2016 NHRA rulebook

just asking as my head guy will not fill them.

[ss3011]

I poured these heads with aluminum yesterday. Interestingly the cast Pontiac pistons I used did not have any metal struts in them. First piece of advice is practice on a head you don't care about first, and the second is make the pour in one shot, trying to add extra aluminum after a short fill may risk having the extra material you pour after, get loose and fall out. I am worried about warping or damaging the head by using a torch to melt the aluminum back out of the passage. Also to prevent aluminum from flowing down the exhaust guide , so I fixed a valve stem into the guide backwards so the tip was flush with the port down in the bowl. That worked out well . I also fabbed up a V -trough to help guide the aluminum past the valve seat. That also worked well. As I said before , Thanks for all the tips. Like anything, the more practice you get the better you get at it !