.050 Over 428FE ?

[67xr7cat]

Jay's mule engine with the .080" spots is a 427 block with the cloverleaf cylinders so you really cannot compare it to a 390 or 428 cylinder.  Everyone has a different answer as to what is acceptable. A lot comes into play and I'd say on 50 year old blocks take off as little as you can.  These are castings and castings can have all kinds of issues and variations.  Sonic testing can be helpful, but is just a tool and can lie.  Who does the sonic test probably matters more as you need to know how to use it properly.

Another thing to consider is if a spot is thin how big is it? Also how long is the cylinder wall.  A tall deck block is more likely to split then a short deck at the same thickness.  A 1/3 to 1/2 fill can help support the cylinder a good bit. Personally a block at .030" over or .080" I check out the same way.  Either can be too thin in spots. Just the .080" is a lot more likely to be junk, but once in awhile the .030" may be too.

[Keith Stevens]

I have spoken to several builders. Two here, and the local FE guru who I spoke too being there are plenty of opinions. He pulled out three blocks. NOS units and showed me the sonic. Many 390/428s were at .200 or less at standard bore. I have an exceptionally thick D4TE block that is at 4.155 and is still just over .100 at the thinnest major thrust. Most are in the .130-140 area.  The block was offset bored to leave as much material as possible. Charles Eller did the work in Arlington, TX. I turned another member here onto him and he brought down the block the local knuckleheads in Oklahoma screwed up the mains on.
There is far too many opinions and not enough hard science on to determine what is safe. Would I run 12.5:1 on a .100 thrust? No. I don't think I would. Would I run it on a 500 HP street engine? Yup. The block that I had that was very weak was a 66 A casting. No main reinforcements and never impressed me thickness wise. I cracked two cylinders at two different points. I wasn't spending any more money on it at that point. The 63 427 block I had also had a headbolt hole break and was very thin. Also standard bore. 
Now that our choices are dwindling I am always concerned about purchases without a sonic map.
 I remember someone talking about safely doing all eight sleeves and furnace brazing the block. I would assume it requires re-machining of all the surfaces.
I would imagine I will go with a stroked 390 block or a BBM block when the time comes again.

[wsu0702]

My dad loves to tell the story about the Hot Rod magazine article that came out in '67 where they took a 352 block out to 428 bore size and ran it on the Utah salt flats.  He said the next year everyone showed up at the drag strip with fresh "428ci" engines LOL.  All of them way over bored 352/390's. Dad said that every single one of them steam cleaned the exhaust system due to split cylinder walls before the end of the season.  Not saying that it cannot be done if the core shift is minimal especially for a cruiser.  But as Ross mentioned you still have pretty thin cylinder walls and ring sealing will for sure be an issue.  I say don't be cheap and just pay the extra $$$ for the real deal and then rest easy.  JMHO.  http://www.mercurystuff.com/articles/352_skiddoo_hello_428.html   

[frnkeore]

At least when the FE was first designed, Fords cylinder wall spec, was .170 min thickness and their max, recommended over bore, was .060. Ford wasn't then, nor are they now, a company that did not do QC, to the highest standards. I'm sure that the former employees, on this forum, will attest to that. You do not inspect every part that is manufactured but, you do inspect as many as it takes to insure good QC. While core shift exists, it should be the exception and not the rule.

That spec should apply, threw at least '62 for blocks designed and built for cars. My '57 dated 4.050 bore, Edsel block, confirms that. It should have .24 between cylinder walls and after 60 years of heavy rust, a .250 Allen wrench, will stick and hold, between cylinders, in the upper part of the core plug hole.

That spec, may have change, around the introduction of the C3AE. Ted Wells, who worked for Valley Head Service and a 60's/70's Ford FE guru, said that the earlier blocks were heavier and he preferred them for his bored, 7500 rpm engines and never broke one.

While many 352's where bored 1/8" in my day (60' & 70's), it still would have left .107 walls, on a well centered core. We didn't have sonic testers in those days but a 1/8" over was very common for all blocks (Olds, Cad, SBC, Linc and yes, the FE) and not many (I don't know of any) broke. My best friend had a 303 Olds he bored 1/8", to 324 and ran a roller cam and 471 blower on it. It never missed a beat in 7 years, in the '32 and put it in a V drive boat, after that.

It would be interesting to get measurements (wall spacing) of C0, C1 and C2 blocks.

I'm not against sonic testers, I own one and will test my blocks. I get my DIF, C scratch back from the hot tank Wed and will test it, this week. It has .190 between cyl.

[blykins]

Boring a block to capacity gets you absolutely nothing except for negative things.   You lose cylinder wall strength and ring seal.   If someone wanted to make the argument that boring them out that far gained horsepower because of valve unshrouding, then I would sit down to that argument and show the horsepower differences between TFS headed 445's and TFS headed 460's. 

I personally wouldn't put any stock in the fact that guys were taking 1/8" out of bores 50-60 years ago and the engines lasted.  Even with blowers and roller cams, they were most likely making way less horsepower than we are making today.   

In response to the original post, I don't see anything wrong with a .050" over 428, as long as it was sonic tested and checked out.  Sonic testing won't show all the weak spots.  I ruined 2-3 good D4TE blocks about 15 years ago trying to get them to a 4.130" bore, even after a good sonic test.  However, a sonic test will show the overall health of the block.  Taking a 428 to .030", .040", and .050" over is the natural overall progression of using factory blocks and rebuilding them over time.

[Joe-JDC]

The whole point of this post was: Is it possible to bore a 428 +.050" over, and the answer is Yes.  Not every 428, but many are capable of that and still be strong blocks.  Some folks here will argue with a fence post.  Joe-JDC

[Lg57]

Amen Joe!

[427HISS]

When doing a sonic test, usually the thinnest spot is recorded, meaning everywhere else is greater than that spot.  After you do several sonic tests, you can begin to recognize the pattern of how a cylinder is shaped.  Many have over .200" in the thrust areas, only to have a spot somewhere that is less.  Many blocks start out thick, go thin, and end up thick at the bottom.  Also, many of the blocks that used antifreeze will be thicker than those in other climates where plain water was used.  Simple logic, but if a block has had antifreeze in it since new, it can still have thick bores even after 60 years.  I do have a block that is making 600 hp with ~125" on the thrust walls at the thinnest spot, and less than .100" on a couple of inside walls.  Next time I tear it down, it will get a half fill of hard block, and a light hone with torque plate.  Joe-JDC

Joe, please give me details about how you got to 600 HP.