Hey i just joined this site i have an 89 chev single cab short box with 252,000km on it 5.7L 350 Tbi runs mint but the valve seals are shot i bought this truck from an old man in 06 and it had 188,000kms its really never been beat up is it worth doing the heads cause i have rebuilt spare heads from the same year of truck

 

well if you have the heads then why not? its all relative, if you dont mind using a little oil then dont change them but if you want to run cleaner i'd swap em out

 

Get them blend ported and rebuilt. Always worth it.