clearance for engine box

[matt]

Im ready to fab the motor boxes for my bertram 28. Wondering what the minimum clearance I can get away with between the exhaust riser and the frp box? Any ideas on the max temp on the riser? Motors are Yanmar 4lhstp
thanks in advance

[Bruce]

Wet or dry risers?

[matt]

Bruce, Im raising the height of the boxes so I plan on coming out of the motor dry then putting in a mixer on the down slope to the muffler.
Thanks,Matt

[scot]

Leave room for sound damping insulation. Even if your not installing it now, you may opt for it later.