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427 Core shift
I am still in the process of finding a new block for my cobra...my hopes were to find a iron side oiler block. I have looked at quite a few now and some NOS service blocks. A lot of the NOS service blocks seem to have "some" core shift as I not seen one without a little bit.
Question...is there any general rule about core shift? For example is some core shift ok?...if so how much would cause me to leave it alone and continue looking?? |
Well, yes... some core shift is ok, some cracks are ok if properly repaired. Most of the marine and industial service blocks were this way and operated fine up to 3,000 rpm. The issue is longevity and the balance / clearance / harmonic issues that occur over 6,000 rpm. You know 427 blocks were color coded from ford for quality right. The best highest quality blocks were pulled off the line and sent to HM & Shelby for racing use. I guess it depends on how fast you want to go and how long you want to go that fast.
You say "new" block. Are you looking for a NOS block or do you man new to you. Perfect NOS blocks are out there but they command a permium. $4,000-5000 for NOS block is not uncommon. I opted for a .015" over fully machined rebuilt unit with MR heads, 2.25" valves ready to assemble that had lived one incarnation as a 1960's-1970's race engine. I essentially traded .015" of overbore for a fully machined (NOS blocks need a couple dozen hours of perp / machine work to be race ready) engine. The heads were similarly worked over. and would have cost $3,000. to duplicate. Have you ruled out a Genesis block or a Pond block? |
Thanks...i have actually had the opportunity to buy two NOS blocks. Both at a reasonable price. (I say that b/c I would really like to use the correct block in my build).
A couple of questions if you don't mind. 1. Both NOS blocks had some factory paint on them..either blue / orange or both....I heard that meant they were designed for passenger cars? 2. Just wondered how much core shift was "tolerable" and if there are specific numbers I should be looking for once it was sonice tested? I have heard that .7 to .75 is ok??? Does that mean anything to you? |
you could try a search here http://www.network54.com/Forum/74182/ these guys know EVERTHING about FE's
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I talked to a rep at Summit Racing and he told me they are now carrying 427 SO from Ford racing. The part number for the cast iron is FMS M6010A427 and cost $3594. He also said there is an aluminum block for $4895. Chas
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Quote:
Genesis blocks... |
Thanks Undy....had me wondering
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If the paint daubs were on the back of the block then yes the 427 blocks were color coded for racing, street, marine and industrial applications. i don't see a listing for a blue and orange daub. But i do see a blue and yellow as a marine block. Also just a blue daub also for a topoiler and sideoiler but both street applications. Service blocks normally came with a blue and white paint daubs. Some block markings denote different machine steps that have been completed if in the lifter valley, side of the block etc.... Where were the paint daubs and what shape were they? Were they on the rear of the blocks? Most are circles and some use a letter beside them. The Genesis and Pond blocks are pretty much an exact copy of the originals. They even have a C5AE-H sideoiler casting number.
G. |
After building many FE;s with 30+ year old blocks I can tell you I've found many NOS "perfect" blocks to have issues from hairline cracks and numerous other issues that take a lot of time to fix!!!! Do yourself a favor, buy a new Genesis (or other). The Ford racng is a Genesis, they cut a deal over a year ago but supply and demand kept them from the market. The new blocks have mods done to beef up the areas prone to cracking on the 427's and more.
MD |
WHAT? You mean you would put a replica 427 under that hood! The horror... :LOL:
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