My block casting number is 3227445 75-79 as I.

THE 258 HAS A STAMP BETWEEN #2 AND # 3 CYLINDERS (ON THE SPARK PLUG SIDE)THE 4TH DIGIT IS EITHER AN --A--B--C--M. THIS IS ON THE BLOCK, NOT THE HEAD.

B---- IS AN EARLY 258, COMPRESSION RATIO FOR THIS ONE IS 7.6 TO 1.

A AND B CAME WITH A 1 BBL CARB (THE CAM IN THESE ARE DIFFERENT THAN ONES THAT CAME WITH A 2 BBL)

C AND M CAME WITH A 2 BBL CARB

M---ORIGIN IS MEXICO

E--F--K--L ARE 232s

I BELIEVE THE HEADS UP TO 1979 WILL WORK ON THE PRIOR ONES

I'M NOT SURE IF "B"s COMPRESSION RATIO WAS IN THE CYLINDERS OR ALSO PART OF THE COMPRESSION CHAMBER IN THE HEAD ( I HAVE NOT RUN INTO THAT MYSELF)

I DO KNOW THAT THE ALUMINUM INTAKE MANIFOLD ON LATER 80s ENGINE WILL WORK WITH HEADERS ON EARLIER 258

I JUST WENT ALL OUT IN THE QUEST FOR BETTER MPGs AND BETTER POWER WHEN YOU "GET ON IT"---A OFFENHAUSER 4 BBL INTAKE COUPLED WITH A HOLLEY 390 CARB W/ VACUUM SECONDARIES. JETTED CORRECTLY FOR MY DRIVING HABITS WITH THE AID OF AN OXYGEN SENSOR, THAT WAS THE TICKET!

I ANSWER A LOT IN THE CJ FORUMS HERE

KEEP ME POSTED OR IF YOU HAVE QUESTIONS, I MAY BE ABLE TO SHARE MORE INFO, I HAVE MEGA PICS, I HATE THE OLE CRAPPY PRESTOLITE IGNITION AND HAVE UPGRADED MY JEEP IN MANY WAYS TO MAKE IT MORE "USER FRIENDLIER"! I HAVE MANY MANY PICS---SOME CAN BE SEEN IN THE CJ FORUMS HERE AT 2 CAR

I LOVE MY JEEPS. HAD 7 TOTAL---STILL HAVE THE LAST 2, "MR. JEEP" '77 CJ 5 AND "WILLY" '46 WILLYS----NEVER HAD ANYTHING ELSE FOR A DAILY DRIVER

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