Bore: 3.875”
Stroke: 4.25”
Piston: Forged
Compression: 9.6:1
Rated Power: 110 HP
110 LB FT Torque
Camshaft: 248  Duration .625” lift
Valve Spring: Ultima
Chrome Nose Cone / Rocker Boxes
Billet Oil Pump
Chrome Tappet Blocks
Ignition included on assembled engines

El Bruto® Series
Ultima 3.875 Bore 100 CI  Engines & Long Blocks
Ultima® is now offering the new “El Bruto” Series Engines which are designed to provide our customers with a U.S.A. built High Performance engine that is priced to be the best value of any engines now on the market. Ultima’s commitment to engineering excellence and competitive pricing brought El Bruto® to life with a completely new designed set of castings emphasizing performance, reliability, and value.
All of the castings in these engines are based on all-new CAD designs cast from C355 aluminum, a common U.S. military alloy known for its stability over multiple heat cycles. The engine components are machined on state of the art CNC equipment for guaranteed dimensional accuracy and repeatability. All of our engines are dynamically balanced using proprietary methods to provide the smoothest running engines on the market and now with our new high flow cylinder heads these engines now can boast the most powerful engines on the market as well!! We think that you will agree these engines are the best value anywhere. 
Case
Made In U.S.A. Cast-in steel inserts guaranteed not to move. Large bore breather for increased crank case vacuum and less blow by. 1/2” Alignment dowels for true line bore. Counterbored stainless allen head case bolts. Close machining tolerances. Made from prime C355-T6 aluminum that is superior in strength to A356. Styling and cosmetic machining for a custom look.
Crankshaft
Forged 4140 Steel. Dynamic balanced for the smoothest running engines in the industry. Light weight 7.44” high-performance H-beam rods w/.792” fins.  Jims Machining shafts and pins.
Cylinder
C355 Casting. Cast-in liners will not move.  All fins are machined for an excellent cosmetic appearance.Cylinder Head
C355-T6 Casting. All fins are machined for excellent cosmetic appearance. Twin Cam Styling. 30 % More fin area than Evolution® style heads for cooler running. 2.100 Stainless Int. Valves. 1.700 Stainless Ex. Valves. Manganese Bronze guides. High Silicon Wire Valve Spring with Chromoly Retainer.

100 CI Complete Engine Assembled
298-250  Complete 100CI Engine, Natural.
298-251  Complete 100CI Engine, Black.
298-252  Complete 100CI Engine, Polished.   

100 CI Complete Engine Unassembled
298-250U  Complete 100CI Engine, Natural.
298-251U  Complete 100CI Engine, Black.
298-252U  Complete 100CI Engine, Polished.

       100 CI Long Block Unassembled
298-266  100CI Long Block, Natural.
298-267  100CI Long Block, Black.
298-268  100CI Long Block, Polished.