| JE Pistons 257986 BBC Flat Top Piston Set 522 CID, 4.560 Bore, 4.000 Stroke, 0.094 Oversize Rod Length 6.135, Deck Ht. 9.780, Comp. Ht. 1.645, C/R 52cc 9.7, C/R 58cc 9.2, C/R 64 cc 8.8, Dome Volume -3.0, Grams 714, Footnotes -, Recom. Ring Set JEP-J100H8-4560-5, These big block pistons are compatible with forced induction, nitrous and angle milled heads. Valve reliefs will accommodate oversized valves and long duration, tight lobe separation cams. Compression Height figured using 9.780" block height with zero deck clearance. Precision CNC machined ring grooves accept 1/16, 1/16, 3/16 rings. Will fit both open and closed chamber cylinder heads.
Includes:
Pin #990-2930-18-51S (174g)
Double spiro locks (#990-042-CS) Ring package designed for: 1/16, 1/16, 3/16 Rings
A fits 3.480
and 3.500 stroke
B Oil Rail Support is Included
C .927 Pin Diameter
D .912 Pin Diameter
E .990 wrist pin
F Indicates 1.040 Pin Diameter
H Indicates 1.094 Pin Diameter
J Indicates 3mm Oil Ring
K .945 Pin Diameter
L Limited Quantities available
M Made To Order
P .975 Pin Diameter
S Solid dome design
W 428 Crank Shaft
X angle milled heads |
When the first Big Block Chevy made it’s debut in 1963 at the Daytona 500, it was referred to as the "mystery motor". Now, over 40 years later, it has been used in so many different applications that it would be impossible to list them all. Described below are some of the most common characteristics of the big block Chevy, in order to help you to arrive at the proper piston selection.
To determine piston compatibility most big block Chevrolet cylinder heads can be divided into two categories; closed chamber and open chamber. The closed chamber head was originally used on the 396 and 427 engines and has a restricted combustion chamber area. All JE flat top and inverted dome pistons will work with most closed chamber heads. JE has a selection of closed chamber domed pistons available as shelf stock. The open chamber style head was introduced on the LS6 and LS7 454 engines and features an average combustion chamber size of 118cc. All JE Big Block Chevy dome shelf pistons may be used with most open chamber cylinder heads. Exceptions are Edelbrock cylinder head numbers #6040, #6045 and #6055, all of which require custom pistons.
Other cylinder heads, such as those with the popular 18º valve angles, require special order pistons unless a specific catalog piston has been designed for them. REMEMBER, always check piston to cylinder head clearance during assembly as shown on the tech page of this catalog. If you have questions regarding the head chamber details on your particular cylinder head JE suggests that you contact the cylinder head manufacturer directly. Another critical area of importance when choosing a piston for the big block Chevy is block deck height and deck clearance. Standard deck height from GM is 9.800" however the GM truck blocks, as well as some aftermarket offerings, have a deck height of 10.200". The "tall deck" block (10.200") as it is commonly known, allows the use of longer stroke and longer rod combinations for increased displacement. JE uses the 9.780" block deck height with zero deck clearance when computing compression heights for all of our big block Chevy pistons except where noted. Use the handy compression height calculator provided on the tech page of this catalog to determine the correct piston for your application. |
