Coating exhaust headers

Looking at these for my C3.
Headers on CL

How would you deal with them? Header wrap? Can they be coated? VHT high temp?

Any issues using them on a 95 LT1?

The only coating that I've found to hole up for any length of time was something does professionally. It needs to be sand blasted, cleaned, coated with whatever hitemp coating your chose and then baked to cure it. Any paint I've used will only last a short time before burning off or flaking off. Surface prep is key no matter what you do.

I've had a professional ceramic coating done at my local powdercoaters. It lasted just as well as the exhaust paint from NAPA but cost 30x as much.

Now I either use high-temp paint or I send it to a real ceramic shop like JetHot. I've melted Swain.

The expense to coat them with Jet-hot can usually buy you brand new headers.

Some guys have had great luck coating them with anti-seize. The grease part burns of and leaves the graphite and other stuff burnt on it. Not pretty, but really keeps rust at bay.

These headers will not work in any way, shape, or form on a 95 LT1. Even if you got past the clearance issues of the different frames, the bolt patterns and head ports aren't the same. They'll work with a wee bit of massaging to the bolt holes. The ports are spaced basically the same, (center ports are a touch further apart on the LT1) but the ports are higher, and d-shaped. Corvettes of that era would likely have oval-port exhaust.

Header wrap is not a wise idea unless you have extreme heat issues. They trap heat when running and trap moisture when cold. They are known to rapidly increase rust.

curtis73 wrote: The expense to coat them with Jet-hot can usually buy you brand new headers. Some guys have had great luck coating them with anti-seize. The grease part burns of and leaves the graphite and other stuff burnt on it. Not pretty, but really keeps rust at bay. These headers will not work in any way, shape, or form on a 95 LT1. Even if you got past the clearance issues of the different frames, the bolt patterns and head ports aren't the same. They'll work with a wee bit of massaging to the bolt holes. The ports are spaced basically the same, (center ports are a touch further apart on the LT1) but the ports are higher, and d-shaped. Corvettes of that era would likely have oval-port exhaust. Header wrap is not a wise idea unless you have extreme heat issues. They trap heat when running and trap moisture when cold. They are known to rapidly increase rust.

I hadn't really looked at the ports on the lt1 heads. So then the headers I had on my old small block are out too then. Suggestions then, for putting exhaust in my C3 with the 95 LT1 in it? Manifolds I guess?

vwcorvette wrote: Any issues using them on a 95 LT1?

Port mismatch. The LT1 engines have exhaust ports raised a half inch or so, but the bolt pattern is the same. LT1 heads require LT1-specific headers.

You probably could get away with cutting the flanges off and welding LT1 flanges on.

Also, those appear to be headers design for side pipes rather than running the pipes out the back. I may be wrong.

IMHO they are a bit overpriced at $200 for a used set of headers. I picked up a nice set of Hedman headers for 40 bucks only lightly used. Not as good as hookers butt work just fine on my application

In reply to Ovid_and_Flem:

Side pipes are the most convenient way to run headers on a C3, IMO. Putting the exhaust under the car can be challenging sometimes.

$200 isn't THAT out of line given that new headers often run in the $800-1500 range for something that complex.

Surface prep is key no matter what you do.

what kind of prep is necessary before sending something out for professional coating?

is glass beading sufficient for a newly fabricated part?

bake used parts to get rid of oil contamination & then media blast?

General clean up is all that's necessary. The shop will chemically clean and blast them before coating no matter what you have done. It's the only way the shop will know they are ready for coating.

Ovid_and_Flem wrote: ...Not as good as hookers butt...

We'll take your word for that!

I used a local shop to ceramic coat several sets of headers. One set was brand new, the swift header was terrible... you can kinda see how rusty that header was here:

and this is what it ended up as:

EDIT: found a better starting pic:

Knurled wrote: In reply to Ovid_and_Flem: Side pipes are the most convenient way to run headers on a C3, IMO. Putting the exhaust under the car can be challenging sometimes. $200 isn't THAT out of line given that new headers often run in the $800-1500 range for something that complex.

I would like to do side pipes and these would give me a start. How tough to replace flanges?

How bad is the port mismatch if everyone and their brother uses lt1 caprice manifolds to put a normal sbc in a 49-54 chevy car?

Pretty bad. First of all, the ports and bolt holes are 1/2" higher overall on the head, so many headers run into floorpan or frame clearance issues because they bolt on higher. This is not really an issue with manifolds since they don't run all the way down to the floor pans.

Secondly take a look at these two heads below. The first one is the LT1. Notice how (in addition to the bolt holes being 1/2" higher) the exhuast port goes much higher above the bolts than below. The second photo is a typical SBC port that is about equidistant top and bottom from the bolts.

Depending on D- or square-port heads, and the headers being used, there could be as much as 1/2" mismatch between ports and headers.

This mismatch isn't as bad going the other way (putting LT headers on SBC) because generally LT1 header ports are larger. The mismatch at least does less obscuring of the port, but its still a bit mismatched.

vwcorvette wrote:

Knurled wrote: In reply to Ovid_and_Flem: Side pipes are the most convenient way to run headers on a C3, IMO. Putting the exhaust under the car can be challenging sometimes. $200 isn't THAT out of line given that new headers often run in the $800-1500 range for something that complex.

I would like to do side pipes and these would give me a start. How tough to replace flanges?

Replacing flanges is pretty easy. I would think getting the tubing to match the different shaped ports would be the tough part. I suspect careful application of one of the cheap impact-wrench spreaders could do it.

But you'll also have to check everything else. Since the ports are higher, those headers might hit the subframe, starter, steering, floorpans, etc.

I would suggest buying them ONLY if you are fully prepared to turn around and re-sell them because they just won't work without a ton of modification.

In reply to patgizz:

Putting LT1 manifold on a SBC isn't as bad because the port mismatch is in the relatively stagnant floor, not the roof. And you can grind out the manifold to eliminate the step. Porting headers is much more difficult

Interesting. While i have a 95 impala and had a 94 caprice, i never touched the engine in the 94 and the impala has an LS swap. Another popular thing for lt1 b bodies who have cheap owners was flowtech afterburner sbc camaro headers.

It is a cheap way to get headers, but the performance is limited due to port mismatching. That is the main reason I never did them on my SS.

I think you also have to dimple the one driver's side tube for the steering shaft and tweak the collectors a bit. So its cheap, but it wasn't an option for me given the hacking that had to be done.

And to top it all off, the headers in the pic don't have what I consider to be a proper collector; no scavenging at all from those collectors.

Not buying. Will keep looking. Thanks gang.