clarification on polishing internals

[chevy_big_block_bro]

Ive read somewhere in these forums that polished intake internals arn't the best thing. Ive polished all the throttle body adaptors for all my mates VN-VR's but ive recently heard that you should take as much meat out as possable but leave it semi rough inside to creat turbulence to achieve a better fuel mixture.
Is this true?
Any comments on this would be great

[garfa]

well what i have heard is that u know how golf balls have that dimpled surface? well apartantly that holds air close to the surface and therefore letting the other air to experience heaps less turbulence. thats why ported manifolds ect... can have dimples on the surface. i dunno if just leaving it rough will have the same effect though. best to ask a place that does manifolds. or an engineer.
cheers

[chevy_big_block_bro]

in theory it sounds good, ill try and find somone with a flow bench

[greenfoam]

Big block dude, the reason you leave them rough is because fuel drops will fall out of the air and stick to smooth polished surfaces, then run into the engine unsuspended and cause wobbly running : ). Ok so this doesn't count on the exhaust ports, where everything can be as smooth and shiny as you can make it, also doesn't count for anywhere that doesn't see fuel mixture, this is the part that counts for fuel injected cars : ). Anywhere upstream from the injectors, all your inlet manifold, bend and throttle body on an injected car can be smooth and shiny like a mirror if you feel like doing that. On a carby car = bad on an injected car = good. Hope that helps : )

Oh yeah if you think that adapter needs smoothing wait till you see some heads from a 1970's Chev V8, it can look like a forest of iron bumps in the ports!. The VN V6 heads look pretty tight too, I reckon you could gain an easy half a second over the quater with a weekends worth of grinding on some heads and a 3 angle valve grind

[chevy_big_block_bro]

i think id rather rip them off and get it pro done, im not to keen on internal mods by my self.
could lead to disaster.
on that note whats it cost roughly to get a head ported and valves done excluding buying new valves for the burned ones