Miles vs problems?

Im just wondering how many miles/kms you guys have on your cars and what problems you've run into. My cars got 348,817kms on it and the head gasket hasnt gone yet (3.3 V-6). Ever. I've had the normal problems with it such as alternator goin, turn signal not workin etc...so what I'm wonderin is am I going to run into some HUGE problem soon? I'm planning on driving it until 500,xxx k, then possibly a rebuild(I'm real easy on cars). Should I do the rebuild next summer? or wait till half a mil. Just wonderin. Thanks for any advice.

if it aint broke....dont fix it

i have 156k on my 95 and besides basic maintenance (oil, spark plugs etc) ive only had to change the alternator. Runs like a champ. I would certainly expect some problems with as many miles as you have on yours but I'm impressed as hell that you have that many and with such MINIMUM "problems"....hope im as lucky as you. But as Tom94gaGT said..jus let it go..if its working dont worry about it

My '93 SE 2.3L 4 cyl has 215k miles on it. Original engine has never had any maintenance other than spark plugs (original head gasket too). Original transmission, though the TCC solenoid failed around 195k miles.
Other non-trivial problems I've run into are:
Water pump dead at 210k
Heater core leak at 180k
Radiator hoses burst at 150k
4 alternators in the past 4 years
Washer-fluid reservoir has leak
Broken upper engine mount at 175k
Ignition switch shorted and melted at 155k
Belt tensioner spring broke at 160k

Other than that it's been aging quite well.