Porting cast iron manifolds
 

I am porting on my stock manifolds (LT1). They are going to get ceramic coated (HPC) when finished. I have one concern. Does porting manifolds leave them prone to cracking? I believe the ceramic coating would help to even out heat distribution so I don't have hot spots.

Thoughts? Experience?

BBB

depends on who and how the ceramic coating is applied

but a couple of times you have to go back and Re-Mill intake sides

because intake was warped from Ceramic Coating Process heat

Ive run 11.88@119 on 97 manifolds.That was a stock shortblock with a stock LT1 cam and 3700lbs..I lightly ported them..Mainly the drivers side was opened up where it enters the cat with a real piece of exhaust tubing..Opened up the ports as much as i could at the engine as well..Lt1 manifold flow pretty well but there isnt much room to open them up safely..

I have not really "ported" stock manfiolds per se, but I have gotten them extrude honed on a couple of "stealth" engines. That process clears out all the crap and sharp edges from the places you can't get a grinder into. Maybe get them lightly extrude honed and then work on them with a grinder in places you think you can open them up and/or imporve flow by hand.