Hi Peeps, I am new to your site and was looking for a bit of advise...

I have been given a Series two ERST cylinder head that has been ported and polished, I am led to believe that the series one C/H had larger exhaust ports - hence laggy

Does anybody know if this is the case?

The reason I am asking is because I had removed and dismantled my engine. I had a bottom end rattle and as I have the engine apart would like to gain the best possible performance once reassembled

Thanks for looking

 

The only diffrence is the shape of the inlet port the s1 is round and the s2 is allmost square

 

Inlet?? Exhaust ports you mean!

Im not 100% certain on this myself, i was led to believe only the early S1's had the round exhuast ports, but either way thats the only difference in the head. A ported/polished S2 head will bring it inline with a S1 head anyway