HI, what do you think about this engine:

http://www.shengines.com/tech_data_new_pt0701A.htm

We have no experience with this engine and therefore have no comment.

upgrade and be prepaired to shell out all kinds of money on gears because they strip out enough as it is...

Happened to me once then I boiled the new spur and adjusted the mesh, and haven't had any problems since.

yeah, i have diff problems now that my stupid spur doesnt strip.

If you are using the new SH engine in the Vulcan and stripping Differential Gears, you may be able to resolve that problem by installing the new metal Diff gears.

Hi i'm in the uk and have an NB16 pretty much the same as
a Vulcan and have got the new SH engine and its not a direct fit
i had to grind the base of the motor to fit the mount also
mod the exhaust header and make up a linkage for the rotary
carb but after all the hassle what a boost in performance.
Its now so smooth on bottom end and very snappy on and
off the throttle and tops out at around the speed as my friends
revo on tarmac will have to see how things wear out been through
a couple of diffs but acme is making metal diffs and as for the old
engine it would really struggle to get anywhere near second gear were
the new one gets there in 10-15 yards.
Also starting is far better too apart from the fitment hassles its
an all win situation and well worth the £41 or about $70 shipped.