Punched out 350 cid

What is the "safe" amount a 350 block can be bored out, or is it already at it's max? It's at 4.125" now. What rotating assembly can be used to bring up the c.i.d.? Just in case I can come up with the extra cash! Any Ideas are appreciated. Thanks.. It's for street use.  

A chevy 350 can be safely bore out .060 over boring it .125 over is way over the safe limit and would not be a street engine at all.  
Professional hi-performance engine builder

Horsepower sells Engines and torque wins races.

agree with above .60 max ,,,,,4.125 is a 400 block , or darts new shp offerings , a stock 350 running water jackets will not handle that bore , even questionable with a filled block  

why would a knowlegdable machinist waste his cutting bits to go that big on a stock 350 block?

does the block have 2 or 3 freeze-out/core plugs on the side?
3 plugs would be a 400 block
2 plugs would be any other factory small-block  
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the red-headed step-child of the mailing list

fuzzy dice, air shocks & N50's rule

Not all chevy small block 400's had 3 freeze plugs on the side some 400 only had 2.  
Professional hi-performance engine builder

Horsepower sells Engines and torque wins races.

find and track down the part number or measure the main bores, 400 mains are bigger then a 350, 350 main housing bore is like 2.6425 or something,  good guess maybe?,  400 as siamesed bores, 350 doesnt  

Thanks guys. Turns out to be a 400 short block. I was given this engine and was told it was a 350 out of a motor home. It had been rebuilt but they never had hardened seats put in the heads and the valves recessed into the seats. So the engine was free! Thanks again.  

as long as nothing else got hurt and the bore is still stock-sized sounds like you've got gold

these blocks are hard to find in good shape and highly sought after by drag racers  
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the red-headed step-child of the mailing list

fuzzy dice, air shocks & N50's rule

The 400 is a great engine. After all it is called a big block in a small package. Think 427 or 434 small block. As for the heads since they need redone check ebay for used race heads. I just finished a 355 with 11:1 and bought everything new except the block and got it all on ebay and spent less than 1200 with stuff like ARP 12 stainless fasteners. Good luck with the project. And get it balanced I built a standard 400 with a Comp Cam good to 6500 and it wound every bit of that a lot.  
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