I have a 351W with a different manifold so I dont think the firing order is correct it says 13726548 I heard that was right but I dont know if it is. Also the same for a 429 I think it is 154263678 but I dont know if that is right. If you are positive on your #,s would you please let me know.
The 351w firing order if it has a real big cam the firing order will change to
the 302 firing order! The reason I bring this up is you say the manifold has
been changed, an I thought that it may be a built engine.