Cracks in LA and Magnum heads....Have you tried running them anyway?

[RustyRatRod]

The Roadkill guys SWEAR by that”K-Seal” stuff.

That's for stopping coolant leaks. It won't work for cracks in the valve seats.

 

[junkyardhero]

The Roadkill guys SWEAR by that”K-Seal” stuff.

i can attest to that, K seal works.

 

[MOPAROFFICIAL]

I sold a set of X heads to a guy who had them magnafluxed. They found a couple of cracks near the spark plug holes. I gave him back his $$ and told him to pitch them....Not sure if he did, or used them anyway.

A lot of them are cracked at the spark plug hole. It about never spreads much more and you can can try grinding the boss down. I'd have used them.

 

[360duster]

we ran already cracked Magnum Heads for a while. Pretty sure the Valve seal is not perfect, but otherwise there was no trouble.

Michael

 

[Michael Harrington]

I had my machine shop build my short block. I posted the receipt on this forum. I also tasked them with finding a set of usable Magnum heads. By doing this I had 2 professionals looking for me. The machine shop and their supplier. They obtained for me a pristine set of castings which were disassembled and cleaned. I paid for them and am almost halfway done with a common sense port and polish. I'm not saying how I'm doing it is cheap. But I need good heads and am not buying Chinese EQ heads and am not interested in aluminum heads even though they are great performers. A shop 30 miles north of me drills Magnum heads for the LA intake pattern and I will do this. I already have new valves and Hughes valve springs and hardware.

 

[Jim Lusk]

I sold a set of X heads to a guy who had them magnafluxed. They found a couple of cracks near the spark plug holes. I gave him back his $$ and told him to pitch them....Not sure if he did, or used them anyway.

Yes, this is where "X" heads crack. I picked up a '69 340 back in the 1980s that had that crack in every chamber. In 2020 I worked on a '70 340 that had a couple of bent exhaust valves. Both heads had two chambers with the same crack. I had a set (an "O" and a "J") that I sold him after I found out that I actually have four "X" heads with no cracks. Both cracked sets found new homes and were presumably fixed. I never removed the heads on my 5.9 in my old Durango, but I do know the heads had been replaced in the year or two before I bought it in 2011.

 

[Hellrats]

All of the LA heads crank near the spark plug holes. My W2 heads are cracked there and have been for 30 plus years. Raced them, overheated them, rebuilt them. Now on a hot street car and still no problem at all. I have also put many magnum heads on with the cracks between the valve seats with no problems at all. I'm sure there are thousands of heads out there running just fine with small cracks in them. Chrysler isn't the only one. As long as the crack doesn't go into the water jacket run them. They are cast, they will crack. Just the nature of the beast.