New MoPar Big Book

Mike Taylor 3601 · 02-22-2011, 08:49 PM

Caution on magnum heads they are very bad to crack they crack between valves,I had a guy bring 6 sets from junkyard all cracked. I pressure test a few with very small fine cracks that barely show when magged they didn't even go across the 45's on seat and they leaked on pressure tester,I thought maybe might not leak.

I called core supplier they said yeah we got 300+ of them a few days later they called back they had checked around 40 heads all were cracked the boss said told them to stop.
I had one guy get a good set on 3rd try rest have ended up buying new castings.
I was told mopar had added material to fix the problem but I don't know if thats a fact or not? Finding good junkyard magnums are like it used to be finding old cast iron 2.5 GM was in late 80's early 90's that were good.
Mike Taylor3601

02-22-2011, 08:49 PM	#10
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,380 Likes: 371 Liked 319 Times in 108 Posts	Re: New MoPar Big Book Caution on magnum heads they are very bad to crack they crack between valves,I had a guy bring 6 sets from junkyard all cracked. I pressure test a few with very small fine cracks that barely show when magged they didn't even go across the 45's on seat and they leaked on pressure tester,I thought maybe might not leak. I called core supplier they said yeah we got 300+ of them a few days later they called back they had checked around 40 heads all were cracked the boss said told them to stop. I had one guy get a good set on 3rd try rest have ended up buying new castings. I was told mopar had added material to fix the problem but I don't know if thats a fact or not? Finding good junkyard magnums are like it used to be finding old cast iron 2.5 GM was in late 80's early 90's that were good. Mike Taylor3601