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350 bored 30 over flat top pistons 2 bolt main

14K views 5 replies 6 participants last post by  runn141 
#1 ·
Hello,

Still a little new here, but I believe I have found a pretty good deal. A mid 70's 350 block bored 30 over with flat top pistons 2 bolt main. A guy here in my town has this motor that he pulled because it was using a little oil between oil changes, but was not smoking. He has a pair of good 350 stock heads. He is pretty much selling it as a short block as he had to steal parts off of it (i.e intake, distributor, oil pan, and all the front accessories. The good news is I have a 305 that I have PLENTY of good parts on including the small chamber 416 heads. When I go look at the 350 block what should I be looking for? I don't want to buy a piece of junk and need to know what kind of red flags to walk away from.?? Thanks! Sorry no casting numbers yet.
 
#2 ·
Issue number 1 is with flat top pistons and small 58cc chambered 305 heads will put the compression ratio over 10.5:1. To get it to run without it detonating itself to death you`ll have to slow the timing way down which takes away any of the power gained by the higher compression ratio.
Secondly, Without knowing what shape the engine is in internally makes it a tricky buy. You could buy it, run it a week and find it needs rod and main bearings. Seeing it run prior to the buy is the best bet when looking for a used engine.
 
#3 ·
i guess you should look closely for sludge....and antifreeze traces ....it sounds like you can rotate the crank so look carefully for scoring of the cylinders and take a good flashlight and look at cam lobes while you are rotating it

as for a pretty good deal are you talking free? if its more then $100 its too much.
 
#6 ·
DoubleVision said:
Issue number 1 is with flat top pistons and small 58cc chambered 305 heads will put the compression ratio over 10.5:1. To get it to run without it detonating itself to death you`ll have to slow the timing way down which takes away any of the power gained by the higher compression ratio.
Secondly, Without knowing what shape the engine is in internally makes it a tricky buy. You could buy it, run it a week and find it needs rod and main bearings. Seeing it run prior to the buy is the best bet when looking for a used engine.
ive used those heads on a 350 .040 over and had no problem with detonation. i only had to retard it 3 degrees, and didnt see that i lost any power.
 
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