Direct Replacement Animal /
205 Domed Pistons
Call 920-207-9180 to place
an order.
Building a higher horsepower Animal just got a whole lot easier.
Now the average guy can build a higher horsepower
Animal with out having to have someone else do any
expensive machine work.
These 3 ring domed pistons are a direct drop in for the stock bore Animal or
LO 206 block.
Something that was not available before.

In the past the stock block needed to be honed or bored approximately .012"
larger to fit an after market piston. Then the pistons also needed about .100"
machined off their top to get the correct pop up.
The average guy does not have a rigid hone, a milling machine or a lathe to
do any of this machine work.

You have to have someone do this for you.

After having this
EXPENSIVE machine work done you have a piston that will fit
the block

The next thing you needed to do was have someone machine the cylinder
head gasket surface down about .070"  to get the compression up to typical
racing engine level.
Machining that much off the head weakens it and makes it more susceptible
to warping and blowing head gaskets.

With these pistons:
You don't have to bore the block!
You don't have to machine the top of the piston!
You don't have to machine the head gasket surface!
These domed pistons eliminate having to do all this time consuming and
EXPENSIVE machine work!

Just drop the piston in and you are ready to assemble the rest of the motor.

It is also lighter than the stock piston.

It's currently available in the following sizes:

Domed pistons NOW available for
the stock rod.

Standard bore  $99.95
.005" oversize   $99.95
.010" oversize   $99.95
.020" oversize   $99.95

Uses the standard Briggs rings (Not included)
Uses the stock wrist pin (Not included)
For stock wrist pin .625" diameter
Use of a Billet connecting rod is HIGHLY
You can use a Briggs World Formula  or
aftermarket rod.
Domed Piston
installed in a stock
No machine work
was required.
It has the proper
skirt clearance and
pop up.
Domed 10.5:1 Animal Piston:

100% CNC Machined Billet Piston
Made from Premium USA Mill
Designed for the Animal, Not a Flathead
Barrel Shaped Skirt Designed From
What The Engine Needs
Gives 10.5:1 Compression with No
Milling of the Head
Use with Std Rod and Stroke
Uses the Std Animal Rings (they are
very well designed)
Lighter than a Stock Piston
Dyno Endurance Tested Under Extreme
Can be Used with Milled Head for Even
More Power
 3" Gas ported piston for Model 15 engine. Notice
the holes above the top ring to apply gas pressure to
the top ring to help seal the ring for more
compression and power. (Google Gas Ported
This is a 3 ring piston with a chrome faced 1mm top
ring, a 1.2mm second ring and a 3 piece oil ring.
Uses the stock Briggs .625" wrist pin.
This piston also has an accumulator groove between
the top and second ring. (Google Piston Accumulator

The rod is made to be used with the stock stroke
forged Briggs Crank. It is 3.572" long and has a rod
ratio of 1.622. It is an over square engine with 3"
piston and a 2.202" stroke.
With the correct cylinder head it will be able to
un shroud the valves for better flow and way more
power than the competition.
Gas Ported  Pistons -- Billet Aluminum
MODEL 15 With 3 inch Bore
This is not an Animal block. You can not bore an Animal to 3" and have any cylinder left!

The Model 15 Briggs block allows you to use a considerably larger piston than the Animal
block because it doesn't have the oil passage on the upper right side of the deck. The oil
passage on the model 15 block is located on the flywheel side of the block. Briggs uses a
sheet metal cover over the passage. (I make a special plate / block support for that
It also has more material between the push rod chamber and the cylinder bore.
Both of these features allow us to use a larger piston an also a head gasket with more
in it.
The Model 15 comes from Briggs with an aluminum bore and an aluminum cran bearing
surface for the flywheel side of the block.
The Faster Motors block has a special bushing installed on the flywheel side that has
to work very well. This style bushing was used for decades on the Briggs 5 HP flat head
and is
currently also used in the Briggs Model 21 (21 cubic inches)  Just like the bearings in your
(not roller bearings) they work great.
The Faster Motors block also comes with a cylinder sleeve installed that has a shoulder at
top to make sure it doesn't move.  The sleeve is also installed with locktite to keep it from

Right now i have the blocks for Open motors and they have a 2.992" Bore.
With the sleeve installed, Piston and rings, .695" Animal wrist pin, Du bushing installed,
with an ARC billet rod