Valve size for 2.7
 

Hi there, if some one can give me an idea of which direction I can take

I'm building my engine 2.7 with JE pistons Scams and webers.

I have a stock CIS motor, do I increase the valve size if so what too?

Matt,

Valve sizes won't change. The ports will require enlarging and the FI holes will need to be plugged.

Were it me, I'd give them to a shop with a good reputation for working on these heads and get them to do the lot - ports, new valves, new guides, valve springs etc... Done properly, they'll provide you with the basis for a great zingy road engine.

Mark.

Do you have a 2.7 normal or a 2.7S? I'm pretty sure that the valve size should be adequate since they are the same dimension as used in the 2.7RS. If you have 2.7S heads, they are most likely fine for street use since I believe the intake ports are 35 mm. If you have 2.7 normal heads, I'd port them out to 36 mm like the 2.2S, 2.4S and the 2.7RS used.