dean51267

I have a set of stock manifilds and heads from a 1993 454, all stock stuff, but in good working order. If needed let me know.

Dean

jmherbert

Cause and effect, or effect and cause?

DURANGOKID59

Thanks Dean. Ill see how everything looks and if need be Ill get a hold of you. Appreciate it

jeffswav

I agree with everyone about the stock manifolds. Best to tear it down before you blame it on the exhaust but a set of exhaust manifolds with a dry riser joint is the way to go. I have a set of EMI's with stainless risers. Don with TP Performance would have a good price on them. I you need to replace your heads I have a set of Penut Port heads with 50 Hrs on rebuild (Gen V 1994) with Manley Valves, Crane springs and 3 angle valve job.

Corbs

Had it happen to my 1991 454 Mag as well, but the exhaust valve failed. Dropped the valve and took out the piston, rod and head. Block split in two areas along cylinder wall - had to replace. The thing you have to consider is all the metal shavings circulating throughout the oil system - it effects the bearings and all. I even found shaving in the intake manifold from the pushing and pulling of air to various cylinders, so other cylinders could be affected. Pull the whole thing apart and go through it. One last item to mention - if metal entered the lubrication system then most likely you will have shavings in your oil cooler. I was told I should replace it as well because it is almost impossible to get all of the debris out. Good luck.

BY U BOY

Rebuild It NOW OR REPLACE IT LATER.

pkspx

Is the rumor true? 454 gen 6 blocks common to crack?

Ted G

iTrader: (1)

Not particularly. On yours I would bet the exhaust valve failed first, then cracked the block from the pieces bouncing around in there. Note that there is no washing of the cylinder or combustion chamber. If a crack forms in the wall it will leak slowly at first and let in a small amounts of water which steam cleans the cylinder. You will also have milky oil in most cases. Usually when a valve fails it is because of a large amount of water rushing in like from a failed exhaust or reversion while backing. If your exhaust checks o.k. then you likely just had a valve fail (weak link in all marine engines) and the head bouncing around in there caused all the other damage.