Did some research, but still confused…

[swissgriff500]

My understanding was that all Griffith 500 have ported and polished inlet manifolds (standard engine specifications as per TVR Power technical information sheets, Sep-96). If this is the case, why then some specialists (well known to Griffith community) propose “polished and ported inlet manifold” as part of their upgrade package for 5l engines? Does it mean that they do some further improvements compared to factory “polished and ported”?
Cheers, Ozren

[2 sheds]

The 500 inlet manifolds are all ported to 44mm, I tell people to leave them alone, because i use a 44mm trumpet set to match, but most specialists use 45mm trumpets which don't quite match, so they adjust/ port manifold accordingly.
The TVR porting is quite good but if you want to be fussy they can always be improved.
Tim

[apache]

I understood it as they are ported by TVR but polishing (now not seen to be a clever idea) is done as a mod. 500s have kin big valves too which is probably why they aint happy about town

[Guillotine]

apparently 500 heads are OVER ported. though still very good of course

specialist engine builders reckon efficiency comes with smaller flowed ports.

negligable for power, bit more to be gained low down and more settled on idle - bit if it ain't broke don't fix it!

mine were worn so off to V8 Developments. see their web site for stage III heads (5.0 engine)

but then mine does have their...

404 cam
twin plenum with matched stage III induction
Mark adams chip!

[2 sheds]

TVR heads are ported using the Tuscan racers as a yard stick, which are fine with racing cams, but as guillotine said with road cams smaller ports work better, having said that they are finished very well.
The satin finish as opposed to high polish is better down stream of the fuel injector.
Tim

[swissgriff500]

thank you guys