1000 and 1026 are both .040 compressed.
Be carefull with the 1000 on a 4.1 (stock bore or any overbore) as if the top of cyl bore has any chamfer on it it may not sit on the block as it should. Best of luck.
hi dan, so i could use the 1026 with the .10 over bore on a stage2 (4.1), thats what i used before the over bore. worked great, ran 35 pounds of boost for 5 years, never blew a head gasket. thanks ed