http://cgi.ebay.com/ebaymotors/Datsun-280Z-Ceramic-Coated-Round-Port-Header-77-78_W0QQcmdZViewItemQQcategoryZ33631QQihZ019QQitemZ290242982125QQrdZ1QQsspagenameZWDVW

I think I have the stock header installed in my Z, will upgrading to something like this provide better performance? Will I get worse MPG?

Is it really even worth doing?

Current snapshot:

If you 75 has the original engine/head then that header won't fit because you should have an N42 head with square ports and that one is for N47, round ports. By itself, a header doesn't do anything noticeable for performance. That's a very general but true statement and I'm sure others will elaborate.

Thanks for the timely response. I was doubtful it would fit, after looking into the service manual. The stock header for the is comprised of 2 tubes exiting from the engine.

The stock header for the is comprised of 2 tubes exiting from the engine.

Actually, that's the downpipe which is connected to the exhaust manifold. A header would replace both. The reason that one wouldn't work on your engine is the difference in the shape of the exhaust ports. It'll bolt on but the header wouldn't match the ports. I've seen people put square headers on round port heads and vice versa but as they say 'that can't be good'. Put a good, free flowing exhaust system on your car with the stock manifold. The performance gain from that will be better that that of just installing a header. IMO, a normal driver type EFI car doesn't need a header.

So the ports on mine are square shaped. If i decide to look for a header, i should find one that looks pretty much exactly the same as the one I listed above, but with square ports ... right?

Thanks

Right.