Hey blue, in coverting to unleaded, could you increase the size of the exhaust valves…
Interested in moving up to a 1.214" ( 31mm) exhaust
Can be done, but not advisable. Reason being, the hardened seats are press fit, so the more material you remove from the seat to fit larger valves, the higher the risk of the seat becoming loose and falling out.
Ah ok… want to get the head on the 1330 upto about stage 4/5 so I can put the twin HIF6’s on… any maybe some little 1.3 rollers and a 300 degree cam..
want to get into the 15’s on the 1/4 this year..
I guess you could try it, so long as you don’t plan on enlarging the inlets too as that will cut into the hardened seats too.
I’m not adverse to a little experimentation… or the alternative is just enlarging the valve seat and a little work on the head…
the inlets are already 1.41" so no need to go any bigger on them..
How much we talking, say using an un modified GT head as the starting point.. ?
Fitting new larger valves would cost next to nothing. You could get that done locally at your local engineers, providing you don’t need new guides then its just a case of having the 4 seats re cut to the right size - £10 tops I recon.
> I’m not adverse to a little experimentation…
had heard that 
Hence the pink wheel arches!
