14 replies to this topic

[Heath]

Yeah that's right they use Holden casts AFAIK and enlarge the ports, install larger valves and shave the faces down for higher compression etc.

Stage 1 = Mild but still more performance oriented than factory
Stage 2 = In between
Stage 3 = Quite hot
Stage >3 = Hotter and less streetable than the stage before it

You don't necessarily have to use a Stage 2 head with a Stage 2 cam or anything, but they both have the same kind of degrees of hotness.

For a Holden V8, VN Heads are simply awesome and no HQ style castings can be made to perform better than VN heads can be made to perform.

For a Holden red six, blue/black 12-Port heads will (apparantly) shit all over a Stage III YT Head (I can't confirm that, it's just what I've heard) but the Holden 12-Ports are a pain in the arse to work on (you can crack them easily just by drilling for hardened valve seat inserts! So I'm not quite sure what the best option is there... alloy head?

[TerrA LX]

For a Holden V8, VN Heads are simply awesome and no HQ style castings can be made to perform better than VN heads can be made to perform.

what rpm and horsepower you talking about because at 300hp at 5000rpm red heads show more torque and power across the rev range.
and yes i know anything over 6000rpm you are waisting your time/money on red heads but just stating that they have their place ie. if you already have a set and only plan on running it up to 5000rpm then spend your money on other things.


as for the orig Q; yella terra started with holden designing heads and performance packages right back with the early holdens comming to light with the X2 and right thru to the VL GRPA heads (and including Brock) so they know their holden stuff

Edited by ALX76, 30 November 2006 - 08:47 PM.

[Mr Lc]

does yella terra still make new 12 port heads, i have a yella terra catalouge which i got at summernats about three years ago, in it they show new 12 port heads one for na setups and one for using superchargers/turbos. it says the heads are redesigned as the standard holden ones are prone to craking, if you can stil buy these how much are they ?

[Heath]

I don't know about that, but brand new 12-Ports were being made for around the $1200 mark with the hardened valve seats already in them and a few other goodies I think. Dunno if YT was doing it or someone else (I wasn't half as intellegent at the time) but I think the main problem was finding one of the bastards.

ALX76, I agree entirely. Most 308 drag cars are all running worked HQ style heads and still pulling awesome figures. I just mean when you wanna go really wild, the VN has a lot more potential, that's all.

[TerrA LX]

^ yella terra sold a brand new cast iron 12 port head at one stage, it was a total rework over the origional.