2.5 build in a classic
 

So I will be living up to my name very soon and getting a 2.5 fitted to my car so I can go for 400bhp for real but....

I never hear or read anything about the Cylinder heads???

Everyone is always going on about the block and semi this and closed that but what about the heads that then fit on to the block?

Should I take it that the heads off any car, age, model i.e. wrx, sti, uk 2000:norty: can just take that sort of power? The vales will not melt? The amount of exhaust gasses will not crack the heads?:eek:

Or should I save up and look at maybe what Cosworth have to offer as they do up rated Cylinder heads

Someone give me the low down please!:wonder:

Thanks:thumb:

Most heads are upto the job, the early phase 1-4 are slightly more restrictive than the later ones, just get yours checked before you put them on your shiny new bottom end:)

I had some hairline cracks around the spark plug hole on my heads, but had them checked and they did not leak so all o.k and car runs fine:D

We've run the 2.5 engines in a number of different specs now. Any of the heads can be used, but some require modification to suit, due to varying chamber sizes. RCM do a CNC process which takes care of that. Cosworth supply superb CNC machined 2.5 heads, as do Ric Wood Race Engines. We've used all of them, and the good news is gas flowing most certainly pays dividends. We fitted a pair of Ric Wood heads on a 2 litre recently, and were amazed at the difference in mid range pick up, compared to the standard heads. It was the first chance we've had to do a back to back, as all we did were the heads. The result was some 50 ft lbs torque increase, for the same boost!

Was that running different valve size / cams, or just a gain from port & polish?

ive got standard uk heads on mine (my99 uk turbo)
running alot more than you state
all fine work well
but recommend sti versions as valves are stronger,