Does anyone know if you can pull apart the aluminum heat shields on the cast-iron exhaust manifolds and then press them back together? I just bought some used OEM exhaust manifolds and I would like to have them media blasted and ceramic coated but I need to have the heat shields taken off them. They appear to be press on where they connect to the manifolds but I can't tell if they are also pressed in where they meet back-to-back.

Does anyone have experience with this and know if you can "service" these aluminum heat shields? I would like to keep them after the manifolds are cleaned up and ceramic coated. I did e-mail the company that will do this service and they said I could have the heat shield tack welded back on, though I would prefer to just press it back on.

 

Don't know about the heat shields, but while the manifolds are off, you could have them extrude honed for better flow. SLP did that with the LT4 engines they put in the limited production 1997 SS's and Firehawks. They supposedly started production using stainless steel manifolds, but then switched to extrude honed stock cast iron.

 

I looked into that and I was getting mixed responses from the various sites I was getting hits on. From what I read, based on the strip experience from a guy who used his stock exhaust manifolds, extrude honing does next to nothing to improve exhaust performance when compared to a stock exhaust manifold matching-up nearly identical F-bodies with same mods when racing. The only thing worth while would be to port or gasket match the exhaust manifolds, however, if the car won't be revved past 5000 RPM then even this gain won't be noticed. I am not sure if anyone has been following me on other forums but I am the guy who wants a factory TPI intake on my LT1, so in the grand scheme of things porting my exhaust manifolds doesn't make any sense.

The only real performance gain is ceramic coating them to add durability, keep them from corroding, keep the engine bay cooler which only helps other components, and helping to keep those exhaust gases as hot as when they first enter the manifold on their way to the catalytic converters. I didn't realize that hotter exhaust gases flow better and leave the manifold faster than one that bleeds this heat into the engine bay, which is what my ceramic shorties are doing. Plus, they are not tuned for the driving I am doing and this explains why I feel like I lost some low end torque with the shorties.

What can I do with the heat shield? I will see if can safely pop them off where they are pressed on the exhaust manifold but I am not sure they will go back on as snug and secure once the ceramic coating is on. If I have to, I will use metal zip straps, the same they use for the header wraps, and anchor the heat shield at these areas. For those areas where the front and back of the heat shield are tabbed together and underneath the manifold, I will have to drill those out so that I can slip the rest of the heat shield off the exhaust manifolds and then when I reassemble them, use some tiny metal screws and nuts to hold them back together.

Also, I am happy that I found an exhaust manifold stud replacement kit. I would rather have studs than mess around with bolts as on my shorty headers.

 

Thread from 2019, haven't logged on in a year, but chancing you may have an update how this went. I'm planning on doing the same if possible.