dead soft copper or dead soft aluminum gaskets hold up much better than composite gaskets.
1 3/4 primaries only help in higher RPM applications
youll do fine with 1 5/8 primaries
3" exhaust provides less restrictive exhaust.
My headman ceramic coated headers lasted for 20+ years since they came out with them and they still look good.

 

I don't think a person would want to use a copper header gasket on aluminum heads. I also have been told that the surface needs to be perfectly flat to use the copper gaskets. The aluminum gaskets seem to conform more to surface irregularities, maybe it is because they are made of a softer metal. Since replacing the composite header collector gasket on my 289 with aluminum ones, I haven't had any exhaust leaks.

 

I've heard people say that they bought them uncoated and made sure that they would fit OK. If they needed a little bending in places they would do that and then send them out to be coated. Since you're putting them in a PU you would probably have plenty of room.

Danny

 

Good idea. Yeah I thought the 1 3/4" might give me a little more top end without sacrificing any low end torque with the 400 sbc, but I guess not. So the aluminum gaskets are favored over the copper ones? I have heard that Percy's aluminum ones are good.

 

headman puts a five year warranty on there coating i dont know of any other compay that does that. i think it would be worth the extra cash

 

just to give you an idea of the coating longevity here is my hedmanns on my 383 that were on there for 20 years

heres a pic of my new husler ceramic coated headers on my 406

 

I don't have a problem with the Hedman coating. What I do have a problem with are manufacturing flaws with the coating applied right over them. I should have taken before and after pictures of my Sanderson headers. They were totally not acceptable in the 'as supplied' condition for coating until I had ground out pieces of tubing hanging in the exhaust path and many pieces of MIG filler wire. The pieces of tubing were worse where the 4 individual exhaust tubes were welded together at the collector and where they were welded on to the flange. I estimate that it took me 6-8 hours to make these acceptable for Jet-Hot ceramic coating. Interestingly, at two different vendors at NSRA York, including the Sanderson display, I looked inside of already supplier coated headers, the same condition existed - nicely covered with their coating - and Sandersons are "premium" header :nono: . Two friends also had the same Sanderson situation with crap similar to mine.

My suggestion - whatever header you do buy, don't have them 'factory coated'. Wait until you are sure they are mechanically acceptable, then send 'em out. Just remember NAFTA - and cheap labor in Mexico which is where many header systems are now being built.

Dave W

 

yeah sanderson headers are not as good anymore.
I didnt have any defects in my headman headers even though they were put together by Mexican migrate workers lol.

 

If you require fabricated headers, you can't go wrong with Lemon's. Camaroman7d had some made for his pro street project Buick, beautiful work. Then get the coating.