Originally Posted by
studabear
Silvertop head doesn't fit without work as far as I know.
The 1.8mm gasket in combination with the blacktop head and ST170 bottom end gives the compression ratio.
Clutch I have no idea, pretty sure you will need a custom flywheel to go with the ST170 6 Speed box, I have seen a good few people say the ratios in that box aint the best for a turbo car, also it is a lot of money to put a LSD into it.
Management would better if it could be programmed, unless you go to MSD for a chip for the current ecu.
Thanks For your answers
You could be right with the box as they fitted it to the st to make it feel slower compared to the MK1 RS. Gary did a gearbox swop using a zetec flywheel so cant see that being an issue.
On the other hand people Turbo St's so I'm prob best asking them.