.60 over cooling issues

[hchad18]

I got a pretty good deal on a 327 short block that needs to be cleaned up. I new it had been bored out but didnt know how much. Well its .60 over and a friend told me I might have cooling issues at .40 over. Is this going to be a problem? I will be running an aluminum water pump and radiator. I haven't paid him yet so nows the time to figure this out. Thanks.

[kenm78]

depends on how thick the cylinder walls are if it is cheap pick it up and GET IT SONIC TESTED but if he wants a bunch for it i would pass. that is my .02 but we can all agree to disagree.

[1968SWBBigBlock]

A 327 should take 60 over w.o issue. These blocks are normally "thick" walled enough to take that kind of cut.
Double check your casting numbers @ mortec.com and make sure you know what you are buying.

[Waylon]

I have a 307 that's 60 over and I've never had an overheating problem...except for the time that stupid flex fan broke and poked a hole in the radiator. I know a 307 is thicker walled than a 327 though...although I don't know...

[texascowboy593]

my 350 is 60 over and it stays in a fairly normal range...even on the hottest Texas days!

[hp1967c10]

I had a 388 (.060 over with stoker crank) and it depended on the conditions. I live in the Dallas/Ft Worth , TX metroplex so it gets extremely hot here. My stroker motor was producing 450 plus hp and I did take it to the track from time to time although it was not a daily driver. The engine was built by a very reparable engine builder in Mesquite, TX (another suburb of Dallas) new dart heads complete roller motor. Needless to say I used a seasoned block and it was bored .060 over to get a clean cylinder. The motor really made the power but the block cracked causing water to mix with the oil. I had a ton of money in this motor and it would still be on the street if I would have had a new block or possibly had it sonic tested prior to assemlby. You could get lucky with the .060 block but I totallly recommend a new block if you are going to build the motor with high quaulity perfomamce parts and invest good money. A new 4-bolt gm block from Jeggs is less than $700.00. It would have been money well spent if I would have got the heads up when I built my stroker motor. Hope this helps.

[Chris27]

I've been running my 388 (.060 over 350 bock, 3.75" crank) for about 5 years in my 69 Beaumont. Engine made 479 HP & 472 lb.ft. of torque on the dyno. Probably have 10,000 miles on it now. Only runs hot sitting in traffic on a very hot day. I'm running an edelbrock aluminum water pump and a stock 3 row rad. The water pump alone made it run 20 degrees cooler. Electric fan would probably help in traffic, but its never been past 220 degrees. My worn out 350 used to run hotter.

[RACINJASON22]

I've seen many engines bored .060 live long health live, but you stated that it needs cleaned up do you know how many miles on it already. If not I stongly suggest not buying until It would be pulled apart and check for any run out or out of roundness on all 8 cylinder walls. If any at all is found leave it sit most all Gm factory blocks have some core shift if only minor, and will leave no room for any further maching. good luck with your truck.

[hchad18]

It was rebuilt started and sat because the heads were used on his daily driver. I can still se cross hatch and no lip also no burn on the top of the pistons.It's definately a 68 327 numbers confirmed. He's asking 150.00 no cam and he thought it was .40 over so if I pushed the issue (which I probably wont because he's a good guy) he'd probably do 100.00. He's oiled the cylinders, I can turn it over firmly by hand. I think it just needs cleaned up because it sat in a garage uncovered. Thanks for you replies. It does help. When my dad was killed a year ago I lost my wealth of knowledge and experience.

[CG]

Ill chime in with the rest. Im running a 60 over 350 with no cooling probs.

[Longhorn Man]

A buddy of mine had an 80 over 350 in tx run in a daily driver mid 80's caprice, sucker was running deep in the 10's on NOS.

[lukecp]

I have a .060 over 350 in my truck, and it has never overheated. It does seem to run a little on the hot side, about 5-10 degrees above my thermostat set point, but it is probably due to my temp guage. I had a 160 degree stat in it for awhile and it ran right at that. Around 35,000 miles on it and no problems, but it is also a pretty mild motor.

[RACINJASON22]

hchad18 with that being said it sounds like a good deal to me. Trusting the seller it a definet plus Good Luck with your truck.

[Fred T]

If you want to know for sure about the bore check the piston top. There should be a stamp with the oversize such as 040. If all else fails, borrow a mike and bore gauge.

The 350 in my 69 turns out to have 080 pistons, done by a po. No cooling problems, but the pistons had to have set him back enough to cost more than another core.