Porting and gasflowing the Mk2 1272cc

[mr brightside]

Hi, the car is actually a 3F Polo Coupe GT, but i posted here because the engine, as i understand it, is basically a MK2 Golf unit.

I'm looking at a comprehensive DIY job, i have all the tooling, but i need some advice concerning one major feature of the exhaust ports. Looking into the exhaust valve chamber with the head upside down and the cam pulley to the left, there is a very obvious lump on the left hand side. What is behind this lump, as the core is heading that way if you stick your finger in the coolant outlet?

Any general tips on carrying out this work? Is there anyone i can ring for advice? I don't want an exchange head, the valve seats are quite good on this and it's been well looked after.

Moderators, please feel free to move this thread to the Polo section, i thought it might get a better response here.

Thanks.

[Crasher]

We built a heavily modified overbored big valve 3F about fifteen years ago (the mechanic that did it is still here and has his old rotten 3F GT sitting at home) but we outsource head work so I can't tell what is behind there, you can also do a 1.6 conversion using the AEE crank.

[mr brightside]

I've reprofiled the standard valves on the lathe.IMG_20220425_124012.jpg

[Crasher]

The secret to these engines is breathing but a double big valve conversion is insanely expensive. A nice conversion would be the 1.6 16v but it's a lot of work.