|
Just my 2 cents:
I would go with the 5/8 for better mid rpm torque (more drivability) and with the 3/4 for better top end power. Also port match the flanges to the head and the primary pipes. Keep in mind that the engine you are planning on buying made the firgures posted on the site by utilizing a particular exhaust system (that would include the extractor/ collector). So i think that with an email and some good faith. you might be closer to your answer...
Chris
__________________
Aircooled 4ever
1973 1303 going towards GL
|