427 so bored 30 over

[misfit41]

I wouldnt be afraid of the motor,,as long as it was properly built,,the only advantage to a lessor honed block would be the chance if you ever had to rebuild you could bore .010 or .020 and clean it up,thats pretty unlikely ,most of the time that would be from wear and miles,your not likely to ever wear out the motor in a sometime driver ,and if you blow it,,99% chance,,get out the sleeves or the welder anyway.my opnion,,Tk

[John 550]

K. wilson
You said All FE blocks over heat ! I disagre . I have had two . The 390 is 30 over
and after a installed the optional 16 inch fan , I have an aluminium radiator , No
problems, The standered bore Side oiler I have also hase no over heating problems ,
I also have a 195 degree t-stat in it to keep the oil temp up for the colder wether .
To say all FE's over heat is to say all uniqes over heat !

[Steve R]

John,
Right , you are. My 427 has never overheated.(while I've owned it) you would think the Houston summers would be a problem. Well they aint. In fact, I don't need to run my fan if I'm going much faster than 15 or 20 mph.
I've heard people talking about the fact that ALL big block Cobras have cooling problems. Another urban legend debunked.
Steven

[427 S/O]

John550, Steven, thanks for the truth.
Most don't build their own engines, they just believe what their builder says.

[rritchey]

Steve R.

When you sleeve a 427 down to a 428, you have to use the thicker sleeves that are made for repairing a cracked cylinder. If you try to put a 3/32" thick sleeve in a std. bore 427 it will just rattle around in the bore. The thicker ones require about a 40 overbore (as I recall), but once you have it in there you will never have to bore it any more and you have tons of cylinder wall thickness. I have never done this myself, but evidently it works well because the racers used to do it a lot.

About your block with the "nick" in the cylinder, It is real hard to say without seeing it but several things come into play. If the scratch is up in the top of the bore, you might have problems. If it is below half-way down, you might not. Seeing as it is not vertical, you might be able to get by with it and not have trouble. If you can hone it and the edges of the scratch are smooth and won't hurt the rings as they pass by, you should try running it. Again, this is assuming the scratch is far enough down in the bore. If it is up high, the compression will have the ring pressed out against the cylinder and the effects of the nick are greatly increased.

[rritchey]

Steve,

Sorry, forgot to address your question about cooling. Remember that a 460 has enough cylinder wall to easily take an 80 thousanths overbore. That means it has A LOT of meat. Probaly not quite as much as the sleeved 427, but at any rate, cooling should not be a problem. The heat will get through the walls to the water, just be glad knowing you have plenty of material there.

[cobra427mnsi]

I had an over heating problem with my FE 406 using the brass radiator sent to me by CR. I had a flexlite blackmagic fan (what a piece of garbage, I went through two of them). Then I had Don Scott send me the Griffin aluminum radiator and the Spal high speed dual fans. No problems now. The fans only come on while idling for a long time on a hot day.

Paul