I believe this is the Kelloggs, long standing Land Rover enthusiasts and restorers on the west coast.
I looked into purchasing a header from them, but it was quite expensive, around $400 US, and they didn't have any stock, said they were going to tool up for some soon. this was about a year ago.
Wise Owl/Rover Park Boys has a mildly reground cam, but it doesn't add any additional lift, just plays with the duration a little. Ray also told me of a contact who will port out the head.
As far as intake goes, a pierce manifold with a 2 bbl weber/holley is great, but only really effective if the head is ported out. I would also think that blueprinting at the same time for both the intake and exhaust would help out a bit.
I'd be inclined to leave the stock cam in it unless you were able to get a higher lift version with similar duration. The stock cam does help maintain your low end power, which is necessary for off road.
As well, putting a header on and opening up the exhaust flow will add extra horses, but very quickly will sacrifice your bottom end torque as much of this torque is based on exhaust back pressure. I would go a bit larger than stock, but not too much.
If you're using a header, whether from Kellogg, or from Turner (http://www.turnerengineering.co.uk/) or from ACR (http://www.automotivecomp.com/) remember the logic of using a header is not really bigger outlet of exhaust, it is to time the exit of exhaust pulses so they create a vacuum to your exhaust ports and draw the exhaust out faster. Therefore, the exit pipe really should only be about the same size as each single header tube of the header — in other words, your exhaust system can still be pretty modest and allow the header to do its job. Add a free flowing muffler to it, but make sure its a quiet one so you don't scare the wildlife!
Of course, these are just my opinions. Other ideas welcome.
Dave
