Will 3.907 pistons work in a stock 98 LS1 block
07-07-2004, 11:20 PM
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Will 3.907 pistons work in a stock 98 LS1 block Two months ago I rebuilt my motor. I had no problems until an aftermarket cam that I had bought started to come apart. The cam put metal shaving all threw my new motor, causing 4 out of 8 eight cylinders to stop seating. In the cylinders that stop seating there are some scratches that I don't think will come out with a finish hone. My question is that I can get my hands on a 3.907 bore forged Mahle piston. My motor is only going to be a cam only car in the 400rwhp range. Can I uses those pistons safely. I keep on reading that 3.905 is the limit, but in a couple instances from sponsors I heard that .010 is the max. Can someone help me out?
07-08-2004, 05:22 AM
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everything I have seen says that the max is .010. I beleive that 3.905 is recommended to leave a little bit of room for a future need to rebuild, like the situation you find yourself in.
07-08-2004, 07:51 AM
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Usually, a replacement piston will be for a 3.903 or 3.905 bore size. IS the piston itself 3.907, or designed for a 3.907 bore? Stock bore is about 3.898, so getting to 3.905 or so is usually just done with a hone using a torque plate. As long as it isn't a 1997 or 1998 block, you should be OK as long as a competent machine shop handles it (i.e. "LS1 friendly shop").
07-08-2004, 10:22 PM
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Beware, the 97 and 98 blocks are only good for 0.004" of hone. GM redesigned the 99+ blocks with different sleeves that will take the 0.010" hone work. Also heed the advice of "LS1 friendly". If the shop says LS1-What? ( quoted from LS1 Performance ) then run like heck.
