Bondo and Scott thanks for replies.
Scott - I am 67 years old and bought my first boat. Needless to say I am learning aloght and making a few mistakes along the way. Just installed used vortec heads on my 5.0 from a engine w/ cracked block. Read later that if block is cracked heads might also be bad. Didn't fire up engine yet but just doing homework if heads are bad will replace them w/ rebuilt or pressure checked set
Make sure you have vortec heads for a 5.0, and not one from a 5.7
vortec 305 heads have 2 casting numbers 12552520 and 12558059 they have same intake port as the 5.7 heads, however smaller valves and smaller chamber ( 58cc vs 64cc) to go along with the smaller bore
