IHRA STK/SS Horsepower Adjustments
6/20/17
Pure Stock Eliminator HP adjustments
● 1994-96 Chevy 350 / 260 / 295 HP - 5 to 290 HP
5/24/17
Stock Eliminator HP adjustments
● 1966 Chevrolet 164/110 /103 reduced 3 to 100 HP
4/18/17
Stock Eliminator HP adjustments
● 1977-79 OLDS 403/284 reduced 14 to 270 HP. The reduction does not include the firebird body style.
3/29/17
Super Stock Eliminator HP adjustments
● 1988-89 Chevrolet Camaro 350/230/235 increased 5 to 270 HP
3/10/17
Stock Eliminator HP adjustments
● 1999-2002 GM Camaro, Firebird and Trans Am 346/305, 320 or 325 /352 increased 6 to 358 HP.
● 1970 Challenger 426/430 increased 5 to 435 HP
Super Stock Eliminator HP adjustments
● Chrysler 426/425/500 increased 2 to 502 HP
● 2009-10 Chrysler 345/305 increased 10 to 315 HP in FGT classes only
2/20/17
● 302 / 320 @ 300 (Y 302 head 270 hp) (X 303 head 280 hp) (306 head 280 hp)
● 347 / 450 @ 420
● 392 / 430 @ 415 (X head 380 hp) (Z head 400 hp)
● 460 / 535 @ 515
● 514 / 600 @ 520
2/13/17
Stock Eliminator HP adjustments
● 1981-83 Ford Escort 97 - 65/79 increased 1 to 80 HP
6/28/16
Stock Eliminator HP adjustments
6/20/16
Stock Eliminator HP adjustments
● 1970 Chevrolet Nova 402/375/405 increased 7 to 412 HP
● 1967 Shelby Mustang 428/345/372 increased 13 to 385 HP
Super Stock Eliminator HP adjustments
● 1972 Dodge 360 275/275 increased to 281 HP
4/19/16
Stock Eliminator HP adjustments
● 2000-2002 Chevrolet Corvette 346/340 increased 3 to 343 HP
3/1/16
Stock Eliminator HP adjustments
● 1981-83 Ford Escort 97 - 65/77 increased 2 to 79 HP
2/17/16
Stock Eliminator HP adjustments
● 1999-2002 GM Camaro, Firebird and Trans Am 346/305, 320 or 325 /349 increased 3 to 352 HP.
2/9/16
Stock Eliminator HP adjustments
● 1977 Chevrolet Nova 350 / 170 269 increased 2 to 271 HP.
● 1990-91 Chevrolet Camaro 350/245-265 HP.
● 1990-91 Chevrolet Corvette 350-247-265HP
8/10/15
Super Stock Eliminator HP adjustments
● 1968-69 AMC 290 / 225-210 increased 10 HP to 220 HP
5/8/15
Pure Stock Eliminator HP adjustments
● 1978 Malibu Wagon 350 / 275 HP - 25 to 250 HP
Super Stock Eliminator HP adjustments
● 1995 Ford 351 300 /.290 HP decreased 10 to 280 HP
4/22/15
Stock Eliminator HP adjustments
● 1978 Chevrolet Nova 350 / 160 - 275 increased 2 to 277 HP.
● 350 /300 - 307 Chevy crate engine increased 2 to 309 HP.
● 350 /385 - 390 Chevy crate engine increased 2 to 392 HP.
4/6/15
Stock Eliminator HP adjustments
● 2010 Ford Mustang 352 285/304 increased 6 HP to 310 HP
2/18/15
Pure Stock horsepower adjustments:
● 1987-1995 Ford Mustang 302 215/213 decreased 3 HP to 210 HP.
Stock Eliminator HP adjustments
● 1967 Ford Fairlane Wagon 390 315/314 decreased 4 HP to 310 HP
6/17/14
Stock Eliminator HP adjustments
• 1969-70 Chevrolet Nova 402/375-395 increased 7 to 402 HP
• 1969 Chevrolet Camaro 396/375-400 increased 2 to 402 HP
Super Stock Eliminator HP adjustments
• 1971 Ford 351-330 increased 2 to 332 HP (SS/GT only)
6/5/14
• 350/330-332 Chevy crate engine increased 2 to 334 HP
• 350/300-305 Chevy crate engine increased 3 to 307 HP
Pure Stock horsepower adjustment
• 1969-70 Chevelle 350 250/230 increased 5 to 235 HP
4/25/14
Super Stock Eliminator HP adjustments
• 1972-73 Buick 455 250-285 increased 3 to 287 HP (SS/GT only)
3/3/14
Stock Eliminator HP adjustments
• 302/270-250 Ford crate engine increased seven to 257 HP
• 1993-1998 Chevrolet Camaro 350/285-325 increased five to 330 HP
12/11/13
Pure Stock Horsepower Adjustments
• 1994 Ford Mustang 302 215/213 reduced 3 to 210 HP
11/20/13
Ford Crate Engines
• 302/320-300 (Y302 head 275 HP) (X303 head 285 HP)
• 392/430 (X head 385 HP) (Z head 405 HP)
• 302/285-265 reduced to 255 HP
4/12/13
• 350/330 crate engine increased 2 to 332 HP
● 1977-79 403 /280 reduced to 260 on Oldsmobile Delta 88-98 Station Wagon and Cutlass only.
1/20/13
• 1967 Ford Fairlane Wagon 390 315/319 decreased 5 HP to 314 HP
7/7/12
• 2010 Dodge 345 305/341 increased 15 to 356 HP
6/6/12
• 1966-67 230 Chevy reduced from 140 to 133
9/5/11
Chevrolet Crate Engine
• 350 / 345/360 reduced 5 to 355 HP
• 350 / 345/365 reduced 5 to 360 HP
• 350 / 355/375 reduced 10 to 365 HP
8/17/11
Ford Crate Engine
• 460 486 reduced 15 to 471 HP
• 460 535 reduced 15 to 520 HP
6/7/11
• 2010 Ford 281/ 235/235 increased 5 to 240 HP.
• 1971 Buick 455/ 315/330 increased 2 to 332 HP.
5/10/11
• 1999-2002 GM Camaro, Firebird and Trans Am. 346 - 342 + 7 to 349 HP.
5/3/11
Chevrolet Crate Engines
• 350 / 300-300 increased to 305 HP.
3/3/11
Stock Eliminator HP adjustments:
• 2002 Pontiac 346/325/342 increased 5 to 347 HP.
• 2009 Dodge 360/275/284 increased 20 to 304 HP.
• 2010 Dodge 345 305/326 increased 15 to 341 HP
2/1/11
Stock Eliminator HP adjustments:
Chevrolet Crate Engines
• 350 /300-305 decreased to 300 HP.
• 350 /330-340 decreased to 330 HP.
• 350 /385-395 decreased to 390 HP.
Ford Crate Engines
• 302/320-300 (Y302 head 285 HP) (X303 head 295 HP)
• 392/430 (X head 390 HP) (Z head 410 HP)
2/9/10
Stock Eliminator HP adjustments:
• 1972 Oldsmobile 350/250 increased 7 to 257 HP
12/23/09
Super Stock Eliminator HP adjustments:
• Ford 460/220/300 increased 5 to 305
9/22/09
Stock Eliminator HP adjustments:
• 1969 Chevrolet Camaro 396/375/390 increased 5 to 395 HP.
• 1982 Jeep 242/190/170 increased 5 to 175 HP.
• 1985 Chevrolet Camaro 305/175-253 increased 5 to 258 HP.
• 1991 Chevrolet Camaro 350/245-260 increased 5 to 265 HP.
7/28/09
Stock Eliminator HP adjustments:
• 1986 Ford and Mercury 302/205 reduced to 200 HP.
3/29/09
Stock Eliminator HP adjustments:
• 1985 Chevrolet Camaro 350/150-250+5 to 255 HP
1/10/09
Stock Eliminator HP adjustments:
• 1973 Ford and Mercury 351-246/253/294+10 to 304 HP (GT only)
5/7/08
• 1996 262 Chevy 170 HP + 10 to 180.
3/1/08
Stock Eliminator HP adjustments:
• 1969 Chevrolet Corvette 427-430(L-88) was 435-5 to 430 HP (cam lift 560/580)
• 1964 Chrysler (Max Wedge) 426 415 HP -5 to 410 HP
1/20/08
Stock Eliminator HP adjustments:
• Ford 392 (X head) /430 410 reduced to 405
• Ford 392 (Z head) /430 reduced to 425
• Ford 347 450 hp rated at 430
11/5/07
Stock Eliminator HP adjustments:
• 1994 Chevy 265 / 200 HP + 15 to 215 HP
• 1966 Chevy 165/100 HP -5 to 95 HP
• 1963 Chrysler (Max Wedge) 426 415 HP -10 to 405 HP
10/12/07
• 1967 Ford Shelby 428 345/366 + 4 HP to 370 HP (Auto)
6/1/07
4/30/07
All vehicles classified as stick only or auto only, accepted to use automatic when listed as stick only, and accepted to use stick when listed as automatic only.
Stock Eliminator HP adjustments:
Pure Stock
11/29/06
Stock Eliminator horsepower adjustments:
Super Stock Eliminator horsepower adjustments:
1971 Ford Mustang 429-375/380-30 to 350HP
4/28/06
Stock Eliminator horsepower adjustments:
• 1973 Ford and Mercury 351-246/253/285+6 to 291 in all Stock GT applications
• All Ford 302/320/300 Aluminum Head Crate Engine / Y 302 Al Head-10 to 290 HP
• All Ford 302/320 Aluminum Head Crate Engine/ X 303 Al Head -20 to 300 HP
• All 1966 Chevrolet 283/220/210 + 5 to 215 HP in Full Size Wagons
12/23/05
Pure Stock horsepower adjustments:
• 1979 Chevrolet 305-160/235/245 – 15 to 230 HP
• 1968 Pontiac Firebird Ram 1 400/335/340/355/360 +5 to 365 HP
Stock Eliminator horsepower adjustments:
• 1969 Mercury Cougar 428-335/375 non ram air -5 to 365 HP
• 1969 Pontiac 350-325 and 330, -10 and -15 to 315 HP
• 1971 Chrysler, Dodge, Plymouth 318-230/195 -10 to 185 HP
• 1972 Chrysler, Dodge, Plymouth 318-150/195 -10 to 185 HP
• All Mopar 360/360 Crate Engines -15 to 345 HP
• All Mopar 360/380/370 Cast Iron Head Crate Engines -15 to 355 HP
• All Mopar 360/380/380 Aluminum Head Crate Engines -15 to 365 HP
• All Chevrolet 454/425 Cast Iron Head Crate Engine / Accepted Aluminum Head
12363392 +15 HP to 440HP
• All Ford 302/320/300 Aluminum Head Crate Engine / Accepted Aluminum Head
X 303 + 20HP to 320HP
9/29/05
• 1968 Pontiac Firebird Ram Air 1 400/335/340/355 to +5 to 360 HP
8/31/05
Pure Stock horsepower adjustments:
• 1972 Plymouth Barracuda 340/240/285 +5 to 290 HP
TOP STOCK: (effective 8/4/05)
• 514 Ford CM @ 430 HP - 5 HP to 410 HP
• 360 / 340 CM Mopar - 5 HP to 335 HP (aluminum head version only)
• 360 / 345 CM Mopar -5 to 340 HP
• Fastburn 350/340/355 - 5 HP to 350 HP
• GM LS-1 (alum) 355 HP - 10 HP to 345 HP
• 1966-1970 CHEV 396/375/370 HP + 15 hp to 385 HP
• 502/502 / 435 HP + 5 hp to 443 HP
• 500 / 445 Mopar (Wedge) CM + 5 HP to 443 HP
6/1/05 (effective 6/6/05)
Pure Stock horsepower adjustments:
Super Stock horsepower adjustment:
2/4/05
1964-66 Chevy 283 / 220 HP increased to 215 (automatic combos only)
1/12/05
TOP STOCK HP ADJUSTMENTS (effective 1/12/05 )
1966-1969 CHEV 427/ 425 / 400 HP - 5 HP to 395 HP
514 Ford CM @ 430 HP - 5 HP to 415 HP
500 / 445 Mopar (Wedge) CM - 7 HP to 438
360 / 345 CM Mopar - 5 HP to 340 HP (aluminum head version only)
360 / 350 CM Mopar -5 to 345 HP
6/2/04
1965 Ford 289 / 271 reduced to 245 hp (pure stock only)
12/19/03
1994 Camaro LT-1 350 275 / 325 reduced to 315 hp (pure stock only)
8/13/03
TOP STOCK HP ADJUSTMENTS (effective 8/13/03)
Fastburn 350/340/365 - 10 HP to 355 HP
1966-1970 CHEV 396/375/385 HP - 15 hp to 370 HP
GM LS-1 (alum) 365 HP - 10 HP to 355 HP
Camaro / Firebird LT-4 350 / 345 - 10 HP to 335 HP
1970 Stage 2 Buick - 5 HP to 385 HP
1966-1969 CHEV 427/ 425 / 405 HP - 5 HP to 405 HP
427/470/ 430 (ZL-1) - 15 to 415 HP
514 Ford CM @ 430 HP - 10 HP to 420 HP
428/335/385 CJ (F5 Head) - 10 hp to 375 HP
500 / 430 Mopar (Wedge) CM + 15 HP to 445 HP
472/525/415 crate hemi - 5 HP to 410 HP
440/six pack - 10 hp to 375 HP
67-71 426 / 410 Street Hemi - 5 HP to 405 HP
360 / 350 CM Mopar - 5 HP to 345 HP (aluminum head version only)
1963-64 Mopar 426/425/415 hp HI Comp. Max Wedge -5 to 410 HP
6/11/03
TOP STOCK and Pure Stock HP ADJUSTMENTS
360/340 CM Mopar +10 to 350 HP (top stock only)
502/502 / 435HP +3HP to 438HP (top stock only)
67-71 426/415HP Street Hemi -5HP to 410HP(top stock only)
1987- 89 Ford 302 / 225 / 215 + 8 HP to 223 (stick combos only)
5/13/03
PURE STOCK HP ADJUSTMENTS
1972 Buick GS 455/250/330 +15HP to 345
1964-66 Chevy 283/220/210 +5HP to 215 (automatic combos only)
1987-89 Ford 302/225/210 +5HP to 215 (stick combos only)
1/13/03
STOCK HP ADJUSTMENTS (effective 1/14/03)
·1964-66 283 / 220 HP reduced to 210 (automatic combos only)
1/6/03
TOP STOCK HP ADJUSTMENTS (effective 1/6/03)
· Fastburn 350/340/355 +10hp to 365 HP
· 514 Ford CM @ 430 HP
· 500 Mopar (Wedge) CM @ 430 HP
· 360/335 CM Mopar +5 to 340 HP
· 351/335 CM Ford + 5 to 340 HP
8/28/02
TOP STOCK HP ADJUSTMENTS (effective 8/29/02)
Fastburn 350/340/365 -10hp to 355 HP
1966-1970 CHEV 396/375/390 HP -5 hp to 385 HP
1966-1969 CHEV 427/425/410 HP -5 hp to 400 HP
428/335/390 CJ (F5 Head) -5 hp to 385 HP
7/31/02
Super Stock
1965 Chevrolet 327 / 250 / 260 HP reduced to 255
Stock
1965 Chevrolet 283 / 220 HP reduced to 210 (automatic combos only)
6/19/02
TOP STOCK HP ADJUSTMENTS (effective 6/24/02)
Fastburn 350/340/360 + 5hp to 365 HP
GM LS-1(alum) 355 HP +10 hp to 365 HP
502/502/423 HP +12 hp to 435 HP
428/335/385 CJ (F5 Head) +5 hp to 390 HP
5/28/02
STOCK HP ADJUSTMENTS (Crate Motors - effective 5/28/02)
350/345/355 @ 360 HP (dish version)
350/345/355 @ 365 HP (flat top version)
350/355/365 HP
360 / 300 / 315 hp (Commando) increased to 320 hp.
5/23/02
TOP STOCK HP ADJUSTMENTS (effective 5/31/02)
Fastburn 350/340/355 + 5hp to 360 HP
GM LS-1(alum) 350 HP +5 hp to 355 HP
502/502/420 HP +3 hp to 423 HP
1963 426/415/410 (low comp) Max Wedge –5hp to 405 HP
1967-69 Corvette 427/400/385 (oval port, 3 X 2) –10 to 375 HP.
Note: Mopar Performance Cylinder head # 4876311 is an approved part on 440 6-pack combinations. (In. 2.140 Ex. 1.810)
5/7/02
TOP STOCK HP ADJUSTMENTS (effective 5/7/02)
4/25/02
TOP STOCK HP ADJUSTMENTS
4/3/02
STOCK and SUPER STOCK HP ADJUSTMENTS (effective 4/15/02)
Ford (Stock)
Ford (Super Stock)
Olds / Pontiac
Chevrolet
Chevrolet (Super Stock)
1/25/02
TOP STOCK HP ADJUSTMENTS (effective 1/25/02)
· 1966-1970 CHEV 396/375/380 HP +5 hp to 385 HP
· GM LS-1(alum) 340 HP +5 hp to 345 HP
· Camaro / Firebird LT-4 350 at 345 HP
· Fastburn 350/340 -5hp to 335 HP
· 502/502/420 HP -5 hp to 415 HP
· 1967-70 Ram Air 4 Pontiac (1970 engine spec) 400/350 HP
· 360/340 crate -5 hp to 335HP
· 472/525/420 crate hemi 5 hp to 415 HP
· 351/340 crate 5 hp to 335 HP
· 460/535/420 crate 5 hp to 415 HP
· 428/335/370 CJ (Steel Standard OEM CJ Head) +5 hp to 375 HP
· 428/335/380 CJ (F5 Head) +5 hp to 385 HP
· 1966-67 Fairlane 427/410/415 (med rise) 410 HP
· 1966-67 Fairlane 427/425/440 (med rise - 2 /4 bbl) 420 HP
9/25/01
TOP STOCK HP ADJUSTMENTS (effective 9/25/01)
8/28/01
TOP STOCK HP REDUCTIONS (effective 8/28/01)
6/27/01
Stock HP Adjustments (effective 7/12/01)
("Crate Motor" HP changes)
Chevrolet
Mopar
6/6/01
Super Stock HP Adjustments
1972 Buick 455 / 315 hp reduced to 300.
Stock HP Adjustments
1970 Olds 455 / 375 hp reduced to 365.
4/26/01
Stock and Top Stock HP Adjustments
Pontiac Firebirds (Ram Air 1,2,3&4)
Top Stock HP Adjustments
2/26/01
Chevrolet Crate Motor
350/345 should read 355 hp for factored horsepower
6/27/00
HP Adjustments (adjustments are for Stock and Super Stock)
5/1/00
Stock Eliminator HP Adjustments
( "Crate Motor" HP changes)
Chevrolet
Mopar
(Stock Eliminator)
Ford
The minimum cylinder head volume for the 360 / 300 Commando combination has been reduced from 70.2 to 64.7 cc. Based upon this change the hp has been increased from 300 to 305.
1/25/00
Stock Eliminator HP Adjustments
Ford "Crate Motor" HP Reductions
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