Plan to over bore gualded cylinder on my G1 need specs

[kdavisman]

Plan to over bore gualded cylinder on my G1 need specs for what I can do. have access to a machine shop and know how just need some basic info, should I have the new piston and rings proir to boring or just open it up to a set DIA and then order the parts etc. if anyone has ever machined their cylinder out is there anything to look for tips or tricks or anything obvious for me to know?

[smallblock450sl]

Cylinder bore std 68.00-68.02mm (2.677-2.678 in), wear limit 68.05mm (0.002 in). Piston oversized 68.25mm (2.687 in) or 68.50 mm (2.697 in). Ring end gap minimum 0.20 mm (0.0079 in) Max 0.40 mm (0.0157 in ) Hope that helped, good luck on your build.

[pachanga90]

Don't bore it until you have the piston in hand.You need to actually measure it,and do your final-hone to size it properly for piston to wall clearance.Specs.are specs,but that doesn't make every part the same.Manufacturing-Tolereances vary,so save a headache and get it right the first time.Look up the Go/No-Go for Piston-to-Wall Clearance,add that to your Piston-Diameter,That is your final bore-size.I've done 350-chevy motors that were supposed to be .030" over,but the final-fit was .029".That extra .001" can mean alot in some cases.A good Cross-Hatch is necessary as well when you are finished(either with a hone,or a Wippity-Bead).That will help retain traces of oil on the cylinder-walls to help the rings seat.Hope this helps.

[kdavisman]

Thanks for the tips. After further inspection I don't think that the cylinder will clean up anyway so just going to replace top end instead of boring.