SPORT powerhead

[Bill Gohr]

000

[Ron Hill]

The last I heard, you had to use Mercury pistons. Are the engine rules posted anywhere?

[Bill Gohr]

The last I heard, you had to use Mercury pistons. Are the engine rules posted anywhere?

I never heard that rule, it was always the weisco, now they allow anything other than Merc Hi Perf top pinned pistons per John Schubert. I don't know where anything is posted for this, I called John

[largecar91]

Here you go. Right from APBA rules FORMULA 1 SPORT TECHNICAL STANDARDS
Engine block is a 5-petal front half 2.5 200HP non o-ring head produced from 1992 to 1999. The intent is to treat this motor on the
same basis as the SST 120 motor; if you can’t change the 120 motor you can’t change this motor. It is also designed so that you
can put all SST 120 components (dressing) on the 2.5 short block. NO O-RING HEAD MOTORS.
1) Please note exhaust port passage to the exhaust chest dimensions are as follows: 1.03 inches (width) 2.50 inches
(height) max. No grinding or blending in the exhaust chest area.
2) Must use top-guided rods—either stock fishing motor rods or Mercury Racing 280 rod or F1 rod. No grinding
with the exception of shot peening. It is recommended if you use fishing motor rod that you use rod bolt #10-848475
3) Any production non-racing top guided 2.5 piston. No grinding or modifying. The Wiseco piston #3137 is the base to
which all other pistons will be compared.
4) Any Mercury production crank is allowed, with the exception of a Mercury crank with heavy metal welded into it (no
late model race cranks). No grinding or modifying.
5) The replacement sleeve is the Advanced Sleeve #1041.
6) The V-6 crankshaft centerline to crankcase/intake manifold surface to be 4.42 +/- 0.01 inches.
7) Intake manifold thickness is 2.0000 +/- .015 (between carb and reed block).
8) Cylinders bored to +0.030 inches oversized must have port heights that measure .015 lower than standard bore.
9) Reed blocks are 10 port = 1.10x.056 or 8 port = 1.05x0.63 reed blocks are allowed with no modifications or grinding.
10) Any reed material is accepted.
11) The only carbs are WH-39, WH-41, or WH-46 carbs with slosh tubes and baffles.
12) Cylinder Head is part #18787 17 Champ 2.5L head 36.5c.
13) Any unaltered Head Gasket is allowed. Part #27-814658 1 is recommended.
14) The SSM #6 and #4 are allowable gearcases and will be inspected per the OPC homologation sheets.
15) No grinding or blending on the blocks! No blending ports or passages! If the factory didn’t touch it, it can’t be altered.
16) Must use stock SST 120 tuner.
17) Tuner can be run dry.
B1 2.13 +/- .030 BW1 0.660 +/- 0.04
B2 2.13 +/- .030 BW2 0.900 +/- 0.04
B3 2.13 +/- .030 BW3 0.660 +/- 0.04
T1 2.170 +/- 0.03
20
T2 2.210 +/- 0.03 TW 2.170 +/- 0.04
E1 1.500 +/- 0.03
E2 1.590 +/- 0.30 EW 2.340 +/- 0.03
MERCURY 200HP MODEL YEARS 1992-1999 NON O-RING HEAD MOTOR
Class Displacement 153.0
Venturi +/- 0.015 1.312
Carburetor Bore +/- 0.015 1.562
Quantity per Engine 3 duplex
Cylinder Bore +/- .003 3.501
Piston Stroke +/- .011 2.650
Rod Length +/- .006 5.500
Deck Height +/- .012 8.31
Flywheel min.

[Bill Gohr]

Here you go. Right from APBA rules FORMULA 1 SPORT TECHNICAL STANDARDS
Engine block is a 5-petal front half 2.5 200HP non o-ring head produced from 1992 to 1999. The intent is to treat this motor on the
same basis as the SST 120 motor; if you can’t change the 120 motor you can’t change this motor. It is also designed so that you
can put all SST 120 components (dressing) on the 2.5 short block. NO O-RING HEAD MOTORS.
1) Please note exhaust port passage to the exhaust chest dimensions are as follows: 1.03 inches (width) 2.50 inches
(height) max. No grinding or blending in the exhaust chest area.
2) Must use top-guided rods—either stock fishing motor rods or Mercury Racing 280 rod or F1 rod. No grinding
with the exception of shot peening. It is recommended if you use fishing motor rod that you use rod bolt #10-848475
3) Any production non-racing top guided 2.5 piston. No grinding or modifying. The Wiseco piston #3137 is the base to
which all other pistons will be compared.
4) Any Mercury production crank is allowed, with the exception of a Mercury crank with heavy metal welded into it (no
late model race cranks). No grinding or modifying.
5) The replacement sleeve is the Advanced Sleeve #1041.
6) The V-6 crankshaft centerline to crankcase/intake manifold surface to be 4.42 +/- 0.01 inches.
7) Intake manifold thickness is 2.0000 +/- .015 (between carb and reed block).
8) Cylinders bored to +0.030 inches oversized must have port heights that measure .015 lower than standard bore.
9) Reed blocks are 10 port = 1.10x.056 or 8 port = 1.05x0.63 reed blocks are allowed with no modifications or grinding.
10) Any reed material is accepted.
11) The only carbs are WH-39, WH-41, or WH-46 carbs with slosh tubes and baffles.
12) Cylinder Head is part #18787 17 Champ 2.5L head 36.5c.
13) Any unaltered Head Gasket is allowed. Part #27-814658 1 is recommended.
14) The SSM #6 and #4 are allowable gearcases and will be inspected per the OPC homologation sheets.
15) No grinding or blending on the blocks! No blending ports or passages! If the factory didn’t touch it, it can’t be altered.
16) Must use stock SST 120 tuner.
17) Tuner can be run dry.
B1 2.13 +/- .030 BW1 0.660 +/- 0.04
B2 2.13 +/- .030 BW2 0.900 +/- 0.04
B3 2.13 +/- .030 BW3 0.660 +/- 0.04
T1 2.170 +/- 0.03
20
T2 2.210 +/- 0.03 TW 2.170 +/- 0.04
E1 1.500 +/- 0.03
E2 1.590 +/- 0.30 EW 2.340 +/- 0.03
MERCURY 200HP MODEL YEARS 1992-1999 NON O-RING HEAD MOTOR
Class Displacement 153.0
Venturi +/- 0.015 1.312
Carburetor Bore +/- 0.015 1.562
Quantity per Engine 3 duplex
Cylinder Bore +/- .003 3.501
Piston Stroke +/- .011 2.650
Rod Length +/- .006 5.500
Deck Height +/- .012 8.31
Flywheel min.

I beleive these are incomplete, there are different rules for different blocks and heads combinations

[largecar91]

I cut off some of the bottom of the page but it does say Wisecos as the piston to be based on.

[dave hensel]

The old specs did say based on the wiseco piston. There are no specs in the new rule book. Which is a problem, Bills powerhead could be illegal tomorrow.

I cut off some of the bottom of the page but it does say Wisecos as the piston to be based on.

[dave hensel]

So I take it that the " E " block is the late model 200 that flows better?

[Bill Gohr]

2.5 200, 36cc heads, fresh bored .020, new weiscos, "E" block, thin head gaskets, SPS rod bolts, 260 exhaust cover, this block was a low hour replacement, no wear on the mains, no decking, no welding, fresh water. $3000 can be delivered to Highlands.

Bill Gohr 847 356 3245 847 274 9378

This motor is sold sorry

[Bill Gohr]

2.5 200, 36cc heads, fresh bored .020, new weiscos, "E" block, thin head gaskets, SPS rod bolts, 260 exhaust cover, this block was a low hour replacement, no wear on the mains, no decking, no welding, fresh water. $3000 can be delivered to Highlands.

Bill Gohr 847 356 3245 847 274 9378

So I take it that the " E " block is the late model 200 that flows better?

No the E is not