boring a 420a .30 over?

[helliviknow]

Hey guys the motor in my gs is starting to get old and I think I'm gonna rebuild it myself as a learing experience. Now im not planning on fordging the internals and boosting it to 20 psi or anything like that. I was thinking more like a mostly stock rebuild but maybe getting the block bored .30 over just to add a few cubes and maybe a few n/a ponies for the daily commute.

My question is I searched for some related info and found some stuff about rod ratios and longer rods and stuff like that. Does boring afftect the rod ratio or would it require aftermarket rods? From what I read I'm pretty sure it does nothing but increase the pistion diamater. Would this affect my a/f ratio a whole lot? I'm guessing more displacement would equal more air. Would the stock computer be able to compensate with enough fuel, or would it require something like safc?

I'm planning on doing some serious studying up on internals and what not before I tear into the motor but I thought I would throw out the question here and see what you all got to say about it. thx

edit: also do you think it would be safe to bore .040 or even .060 on a 420a?

[-Josh-]

Changing the bore wont effect the stroke at all. You shouldn't need any kind of SAFC if all you're going to do is bore it, your computer should be able to compensate for everything(that's what sensors are for). And i doubt you would want to bore a 4 cylinder over any more than that.

Edit: You might not even necessarily need to get it bored over either, you could just get it honed a bit if the cylinder walls aren't bad.

Also when you install the swinging assembly or anything mechanical moving parts for that matter, make sure you use assembly lube. And double check EVERYTHING when you torque it down, one untorqued main bearing bolt could cause some serious problems, same thing with any bold that needs to be torqued down. Make sure you check or have your cams, crank etc... checked with a Micrometer to see how much work actually needs to be done (size of the bearings for instance). Since this is your first time, just make sure you take your time and get it right more than anything.

[helliviknow]

great info thanks for the advice...