bn

I have a set of stainless marine exhaust and risers on my 502 MPI’s. I had water in the oil in both motors. Heads, block, manifolds, etc all checked out ok with no leaks. They are both being completely rebuilt and converted into stock 500 EFIs. I have read that some people have resolved reversion issues by extending the risers. My mechanic wants to weld 10” more pipe and extend the exhaust tube. Stainless Marine said these risers won’t work on 500 EFIs and that extending them won’t help. Anyone know if these will work on 500 EFIs or if I can extend the risers and if not, why not?

The cams are Crane Cams part number 169621 with copper plated cores.

Thunderstruck27

I don't want to sound like a S**** A**. but it sounds like SM already answered your question.

bn

Understand, but at $950 for each riser X's 4, I need a second opinion. Adding 10 inches seems like it would eliminate the possibility of reversion and I have read other threads where this worked.

Just looking for others that may have experience with this.

bigredbaja

I had a set of IMCO Power Flow's on my 502 with short risers, added 8" to the risers and still got the oil milkshake, i did a lot or research and one thing i find out was that at some point in time cracks in the water jacket were an issue. Mine even passed a pressure check but when they did a pressure check with water the failure appreared...cracks in the water jacket. Mine were 13 years old so that may have been the reason mine failed.

bn

Is there any way to test the risers for leaks? I tested the manifold by capping off the hose going to the risers.

Young Performance

The only way is to just flow water through them. You can't really build any pressure though. You can try stuffing rags in the outlets to slow the water a little but that's about it.
Eddie

Thunderstruck27

Understood...I hope you can find a fix!