hi have a motor knock in my olds 350 need advice have a torn apart 455 30 over Ga heads that needs a rebuild,can buy a olds 307 out of a hurst olds 140 k for $300 buy home rebuild 350 for a$1000 or a 403 with 100k for $500,any help would be great.

 

If I where you I would buy the 403 and then either tear down the 350 or put the 455 back together at a leasuirly pace. A "9" 307 has a little bit of power but I think the 403 is a better choice

 

If you use the 403, check the timing chain before installing, as they start going bad at about 80k - if it's been sitting, the water pump bearing seal usually dries out, too.
Both easier to do before installing.