This is an example of an open Animal.
The variations possible of this engine package
are to numerous to list. This particular one has a
Faster Motors billet head with a Mikuni
carburetor, stroker kit, big bore, Faster Motors
1.25 roller rockers, Faster Motors billet side
cover with dual crank ball bearing and ball
bearing cam, billet adjustable tool steel cam,  
dual valve springs with titanium  valve spring
retainers, nitrided valves, Faster Motors block
support behind the flywheel, etc
These motor can range in price from $1500.00
to $3000.00 depending on your budget.
Please don't ask for an estimate with out knowing
what you want.
It's better if you tell me what you are prepared to
spend and i will tell you what you get for that
amount of money.
As a general rule for open motors you get about
1 horsepower for every $100.00 you spend.

$1500.00 gets you about 15 Horsepower.
$2000.00 gets you about 20 Horsepower.
Those HP numbers are on my dyno.
Be aware that 20 Hp on my dyno is often going
to be 30 HP on someone else's dyno.
Be careful what you believe.
If someone tells you they can get 35 HP out of a
stock block  250 cc Animal I'd hang up on them.
As a general rule their dyno is screwed up by
accident or on purpose.