I am going to build my motor in 2 months.
I have a stock EFII XR6, 5 speed manual with 3.70LSD diff ratio, that has done 165000kms.
I want to try and get better economy or the same but get
it as loud and lumpy as possible.
Anyone got any ideas about the best things to do.
Including Head, valves, gaskets?

if you want the same or better economy you need to focus more on getting the burnt gasses out.

the theory is to lessen the pumping losses. (the energy used to push gasses out of an engine)

as such use the biggest exhaust valve you can fit in. but i think the XR6 one is already close to the limmit here.
exhaust ports can be modified also.
modifying intake porst for better flow will cause a drop in economy.

pace maker comp extractors and a 2.5 inch exhaust.
stock cams are best used for this too. as most after market ones will cuase a drop in economy.

loud is easy to get. use a straight through muffler with no resonater.

as for lumpy, cams that give a lumpy idle WILL cuase a drop in economy.

Forgot to mention I have the extractors already.
With the exhaust will it be legal and not too loud for the boys in blue.

the one said will get you plenty of tickets for noise.

you need a try flow muffler and a resonator to keep cops happy

Get the ACL overhaul kit with hi vol oil pump and ballance, Wade ll cam, 2 1/2 exhaust use quality muffler and resonator up front It'll still have a note.Watch that compression doesn't get too high for you can't change advance curve only retard overall..Making it lazzy @ low rpm....
The ACL kit should be around $700 with gasgets, pistons, ring ,bearings,oil pump,wealsh plugs etc order new head bolts $40...While you are at it fit new water pump...

a good flowing cat (modified falcon cat if in good condition or an aftermarket hi-flow cat) and a straight through muffler on the exhaust will just keep the exhaust noise quiet enough that cops wont book you for it. But don't obviously rev it up around them...

Is the XR6 cam different from the standard ones.
And roughly by how much as a guide compared to a stage 2 cam.