Share |
GM LS Asymmetrical FSR Flat Top

GM LS Flat Top Our brand new Asymmetrical FSR (Forged Side Relief) forging design allows for the use of the most popular stroke and rod combinations while eliminating reluctor wheel clearance problems. Asymmetrical forging design maintains a larger skirt on the heavily stressed major thrust side, while reducing friction with a smaller skirt on the minor thrust side. The result is a high strength, lightweight piston that significantly reduces friction in your engine. Lightweight and extremely durable, these pistons are machined for 1.2mm, 1.5mm, 3.0mm rings.

Combination 12° (LS7 Only) & 15° Valve Pockets

Features:
Accumulator Grooves
Double Pin Oilers
Offset Wrist Pin
Includes:
Pin #945-2250-15-51C (105g) For use with 6.098” Rod Length
Pin #927-2250-15-51C (106g) For use with 6.125” Rod Length
Round Wire Locks # 927-073-MW
New for 2013!
GM LS Asymmetrical FSR Flat Top
GM LS Asymmetrical FSR Flat Top
STD Bore: 4.000" LS2 / 4.065" LS3 / 4.125 LSX
Ring Packaged Designed for 1.2mm, 1.5mm, and 3.0mm Rings
Note: 1.340 Compression Height Pistons utilize .945" Pin Diameter and 6.098" Rod Length.
*** LSA & LS9 Engines require oil squirter location modification for clearance. ***

Click here to see matching JE Pro Seal Head Gaskets!

Tech and Installation Tips
Valve Relief Diagram
Part # CID Bore Stroke Rod
Lgth.
Block
Ht.
Comp.
Ht.
Head Cubic Centimeters
64cc 68cc 70cc
Compression Ratio
Dome
Vol.
Gram
Wt.
Footnote Oversize Recom.
Ring Set
311990 413 4.000 4.100 6.125 9.240 1.065 11.8 11.3 11.1 -5 Call B, M, V STD LS2 JG3108-4000-7
311991 413 4.005 4.100 6.125 9.240 1.065 11.9 11.3 11.1 -5 Call B, M, V .005 LS2 JG3108-4000-7
311992 414 4.010 4.100 6.125 9.240 1.065 11.9 11.4 11.1 -5 Call B, M, V .010 LS2 JG3108-4010-4
311993 418 4.030 4.100 6.125 9.240 1.065 12.0 11.5 11.2 -5 Call B, M, V .030 LS2 JG31F8-4030-2
311994 426 4.065 4.100 6.125 9.240 1.065 12.2 11.6 11.4 -5 Call B, M, V STD LS3 JG31F8-4070-0
311995 427 4.070 4.100 6.125 9.240 1.065 12.2 11.6 11.4 -5 Call B, M, V .005 LS3 JG31F8-4070-0
311996 428 4.075 4.100 6.125 9.240 1.065 12.2 11.7 11.4 -5 Call B, M, V .010 LS3 JG31F8-4075-5
311997 429 4.080 4.100 6.125 9.240 1.065 12.2 11.7 11.4 -5 Call B, M, V .015 LS3 JG31F8-4075-5
311998 438 4.125 4.100 6.125 9.240 1.065 12.5 11.9 11.6 -5 Call B, M, V STD LSX JG31F8-4125-2
311999 439 4.130 4.100 6.125 9.240 1.065 12.5 11.9 11.7 -5 Call B, M, V .005 LSX JG31F8-4135-2
312000 440 4.135 4.100 6.125 9.240 1.065 12.5 12.0 11.7 -5 Call B, M, V .010 LSX JG31F8-4135-2
312001 445 4.155 4.100 6.125 9.240 1.065 12.6 12.0 11.8 -5 Call B, M, V .030 LSX JG31F8-4155-3
312002 451 4.185 4.100 6.125 9.240 1.065 12.8 12.2 11.9 -5 Call B, M, V .060 LSX JG3108-4185-3
311976 402 4.000 4.000 6.125 9.240 1.115 11.6 11.1 10.8 -5 Call B, V STD LS2 JG3108-4000-7
311977 403 4.005 4.000 6.125 9.240 1.115 11.6 11.1 10.8 -5 Call B, V .005 LSD JG3108-4000-7
311978 404 4.010 4.000 6.125 9.240 1.115 11.6 11.1 10.9 -5 Call B, M, V .010 LS2 JG3108-4010-4
311979 408 4.030 4.000 6.125 9.240 1.115 11.7 11.2 11.0 -5 Call B, M, V .030 LS2 JG31F8-4030-2
311980 405 4.065 4.000 6.125 9.240 1.115 11.9 11.4 11.1 -5 Call B, V STD LS3 JG31F8-4070-0
311981 416 4.070 4.000 6.125 9.240 1.115 11.9 11.4 11.1 -5 Call B, V .005 LS3 JG31F8-4070-0
311982 417 4.075 4.000 6.125 9.240 1.115 11.9 11.4 11.2 -5 Call B, M, V .010 LS3 JG31F8-4075-5
311984 418 4.080 4.000 6.125 9.240 1.115 12.0 11.4 11.2 -5 Call B, M, V .015 LS3 JG31F8-4075-5
311985 427 4.125 4.000 6.125 9.240 1.115 12.2 11.6 11.4 -5 Call B, V STD LSX JG31F8-4125-2
311986 429 4.130 4.000 6.125 9.240 1.115 12.2 11.7 11.4 -5 Call B, V .005 LSX JG31F8-4135-2
311987 430 4.135 4.000 6.125 9.240 1.115 12.2 11.7 11.4 -5 Call B, M, V .010 LSX JG31F8-4135-2
311988 434 4.155 4.000 6.125 9.240 1.115 12.3 11.7 11.5 -5 Call B, M, V .030 LSX JG31F8-4155-3
311989 440 4.185 4.000 6.125 9.240 1.115 12.5 11.9 11.7 -5 Call B, M, V .060 LSX JG3108-4185-3
323978 392 4.000 3.900 6.125 9.240 1.165 11.0 10.5 10.3 -5 378 V STD LS2 JG3108-4000-7
323979 393 4.005 3.900 6.125 9.240 1.165 11.0 10.6 10.3 -5 379 V .005 LS2 JG3108-4000-7
323980 394 4.010 3.900 6.125 9.240 1.165 11.0 10.6 10.3 -5 380 M, V .010 LS2 JG3108-4010-4
323981 398 4.030 3.900 6.125 9.240 1.165 11.1 10.7 10.4 -5 385 M, V .030 LS2 JG31F8-4030-2
323982 405 4.065 3.900 6.125 9.240 1.165 11.3 10.8 10.6 -5 388 V STD LS3 JG31F8-4070-0
323983 406 4.070 3.900 6.125 9.240 1.165 11.3 10.8 10.6 -5 389 V .005 LS3 JG31F8-4070-0
323984 407 4.075 3.900 6.125 9.240 1.165 11.3 10.8 10.6 -5 391 M, V .010 LS3 JG3108-4075-5
323985 408 4.080 3.900 6.125 9.240 1.165 11.4 10.9 10.6 -5 395 M, V .015 LS3 JG3108-4075-5
323986 417 4.125 3.900 6.125 9.240 1.165 11.5 11.1 10.8 -5 408 M, V STD LSX JG31F8-4125-2
323987 418 4.130 3.900 6.125 9.240 1.165 11.6 11.1 10.8 -5 409 M, V .005 LSX JG31F8-4135-2
323988 419 4.135 3.900 6.125 9.240 1.165 11.6 11.1 10.9 -5 411 M, V .010 LSX JG31F8-4135-2
323989 423 4.155 3.900 6.125 9.240 1.165 11.7 11.2 10.9 -5 415 M, V .030 LSX JG31F8-4155-3
323990 429 4.185 3.900 6.125 9.240 1.165 11.8 11.3 11.1 -5 420 M, V .060 LSX JG3108-4185-3
311961 364 4.000 3.622 6.125 9.240 1.304 10.6 10.1 9.9 -5 Call V STD LS2 JG3108-4000-7
311955 364 4.000 3.622 6.098 9.240 1.340 10.6 10.1 9.9 -5 Call K, V STD LS2 JG3108-4000-7
311956 365 4.005 3.622 6.098 9.240 1.340 10.6 10.1 9.9 -5 Call K, V .005 LS2 JG3108-4000-7
311962 365 4.005 3.622 6.125 9.240 1.304 10.6 10.1 9.9 -5 Call V .005 LS2 JG3108-4000-7
311963 366 4.010 3.622 6.125 9.240 1.304 10.6 10.2 9.9 -5 Call M, V .010 LS2 JG3108-4010-4
311957 366 4.010 3.622 6.098 9.240 1.340 10.6 10.2 9.9 -5 Call K, M, V .010 LS2 JG3108-4010-4
311958 370 4.030 3.622 6.098 9.240 1.340 10.7 10.2 10.0 -5 Call K, M, V .030 LS2 JG31F8-4030-2
311964 370 4.030 3.622 6.125 9.240 1.304 10.7 10.2 10.0 -5 Call M, V .030 LS2 JG31F8-4030-2
311965 376 4.065 3.622 6.125 9.240 1.304 10.9 10.4 10.2 -5 Call V STD LS3 JG31F8-4070-0
311959 376 4.065 3.622 6.098 9.240 1.340 10.9 10.4 10.2 -5 Call K, V STD LS3 JG31F8-4070-0
311960 377 4.070 3.622 6.098 9.240 1.340 10.9 10.4 10.2 -5 Call K, M, V .005 LS3 JG31F8-4070-0
311966 377 4.070 3.622 6.125 9.240 1.304 10.9 10.4 10.2 -5 Call V .005 LS3 JG31F8-4070-0
311967 378 4.075 3.622 6.125 9.240 1.304 10.9 10.4 10.2 -5 Call M, V .010 LS3 JG31F8-4075-5
311968 378 4.080 3.622 6.125 9.240 1.304 10.9 10.4 10.2 -5 Call M, V .015 LS3 JG31F8-4075-5
311969 387 4.125 3.622 6.125 9.240 1.304 11.1 10.6 10.4 -5 Call V STD LSX JG31F8-4125-2
311970 388 4.130 3.622 6.125 9.240 1.304 11.1 10.6 10.4 -5 Call V .005 LSX JG31F8-4135-2
311971 389 4.135 3.622 6.125 9.240 1.304 11.2 10.7 10.4 -5 Call M, V .010 LSX JG31F8-4135-2
311972 393 4.155 3.622 6.125 9.240 1.304 11.3 10.8 10.5 -5 Call M, V .030 LSX JG31F8-4155-3
311973 399 4.185 3.622 6.125 9.240 1.304 11.4 10.9 10.6 -5 Call M, V .060 LSX JG3108-4185-3

- Denotes part # has been issued a new part #. A list referencing old part #s to their new counterparts will be available shortly.


JE Pistons 10800 Valley View Street Cypress, California 90630 - Sales/Technical Assistance | Careers @ JE
Copyright © 2017 JE Pistons Inc. All Rights Reserved - Use of this site is subject to the following list of Terms & Conditions.