5 replies to this topic

[chipmongrel360]

hi, i'm planning a 998 engine build and i've found a guy on gumtree selling a couple of 1275 heads just down the road from me

i have a few questions for you guys

1 - the guy is asking for £90 for a ported 1275 head, is this a fair price?
i've asked him for close-up pictures of the porting work done to it so i can get your opinions on how good the porting is.

2 - he also has what he describes as a big valve race 1275 head. would this work on a 998, with an uprated cam and the like? and if it did work, would the benefits be much greater than the ported 1275?

cheers, Chris :)

[Ethel]

12g295 (998 Cooper) would be my preference but a near standard 12g940 (1275) can work well. If you're going to increase the valve lift with a cam you will need to think about pocketing the block.

[chipmongrel360]

12g295 (998 Cooper) would be my preference but a near standard 12g940 (1275) can work well. If you're going to increase the valve lift with a cam you will need to think about pocketing the block.

from what I've read the 12g295 head and the 12g940 head provide similar results on a 998 if set up correctly, though I could be wrong? I think i've settled on using a 12g940 head anyway, simply because it'll be easier to find.

[lewistranter]

Personally it would be the 12g295 as I've just bought one:) but they sell for stupid money on eBay!
Obviously if you get the 940 then fair enough, either way theyre both much better than standard 998 heads!

[Cooperman]

With a 12G940 head onto a 998 block you'll need to do some careful measuring, especially if you want to fit a higher-lift cam. The valves may clear the block, may need to be recessed deeper into the combustion chambers or the block may need stripping and pocketing.
With a 295 head the compression ratio needs to be measured and the head skimmed to get it right.

[Turbo Phil]

You'll also need to measure the chambers in the 940 head if you decide to use it. Fitting one will raise your compression considerably, even if it's standard & more so if it's been skimmed.