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#1
11-09-2019, 05:42 PM
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455 Main Bore Diameters
Could someone tell me what the main bore housing diameter for a 455 should be? Mine measure 3.4264-3.4268 without bearings installed and caps torqued. I am using a telescoping gauge and calibrated .0001" mic for measurements.
The crank main journals have been cut .010".
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#2
11-09-2019, 05:59 PM
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3.4380-3.4390 is the range. Trying to hold the main housing bores near the middle of that range is best. Larry
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#3
11-09-2019, 06:09 PM
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Then how did beertracker's get smaller?
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My Pontiac is a '57 GMC with its original 347" Pontiac V8 and dual-range Hydra-Matic. |
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#4
11-09-2019, 06:29 PM
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I'd say he needs to remeasure it?
This is the block measurement without the bearings in the bore correct? 
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John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
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#5
11-09-2019, 08:36 PM
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Quote:
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#6
11-09-2019, 11:20 PM
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I re-measured #1 main housing bore (no bearing installed, cap torqued) and the number was the same. So I am reading the mic correctly and the number is too small. I paid the shop to run a align bore test and they told me my block does not need a align bore so none was performed. Apparently my shop did not not check the main bore housing diameter. I supppose that is extra money for that service?
Does anyone have any solutions beside having the main housing bores re-bored to spec? I suppose that is called a align bore job? The other solution is to quit while I am ahead.
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#7
11-09-2019, 11:35 PM
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You need to get a dial bore gauge.
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
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#8
11-10-2019, 12:07 AM
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This ^. Or take it to ANOTHER shop to check while you wait. ( I wouldn't go back to them for any work )
Your readings are over .011" too small |
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#9
11-10-2019, 02:21 AM
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Did you use a telescoping snap gauge? Not nearly accurate enough for measuring a precision hole down to .001. You need a dial bore gauge with a dial readout. Even a cheap Fowler with a .0005" dial would be OK.
.011" too small is a gigantic, unimaginable undersize. No way a crank would rotate with housings that small. It's got to be a measurement error?? The correct machining procedure would be a line hone to correct slightly under/oversized crank tunnel with original caps. Line bore is a more involved and aggressive process for fitting replacement caps. Do you know if the caps are original to this block?
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I could explain all this to the girl at the parts store, but she'd probably call the asylum. White '67 LeMans 407/TH350/Ford 3.89... RIP Red '67 LeMans. 407/TH400/Ford 3.25 Last edited by chiphead; 11-10-2019 at 02:31 AM. |
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#10
11-10-2019, 07:40 AM
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The your motor has the same main Bore size as the 421 listed here.
The first shot list Bearing clearance ranges for street motors, and the second shot for race. This info posted was out of the Federal Mogal Bearing book.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
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#11
11-10-2019, 10:44 AM
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Are you seeing any difference between up down measurement and parting line measurement? Does parting line have a lip or stair step that you can feel? Buffalo Springfield "For What It's Worth" There's something happening here What it is ain't exactly clear Clay |
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#12
11-10-2019, 10:47 AM
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Quote:
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Last edited by beertracker; 11-10-2019 at 10:52 AM. |
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#13
11-10-2019, 11:01 AM
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Quote:
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#14
11-10-2019, 11:32 AM
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All measurements were taken at 12:00 and 6:00 positions. Will check 9:00 and 3:00 positions. No lip or stair step felt or gap at parting line. Agree with Buffalo Springfield
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#15
11-10-2019, 03:27 PM
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Most times when the main caps are not original to the block the main saddle is actually larger than spec, not .011 too tight. At this point, you’d be better off to take the block back to the original shop and have them mic the main saddle with you present. Take a Sharpie and write each measurement on the pan rail.
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“It takes considerable knowledge just to realize the extent of your own ignorance.” Dr. Thomas Sowell |
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#16
11-10-2019, 06:31 PM
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Quote:
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#17
11-10-2019, 10:04 PM
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Measure at 70F, two mesurements where 1 measure is 90 degrees from the other.
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#18
11-13-2019, 06:51 PM
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Problem solved I was mis-reading the mic. I was one decimal place off. Thank to all who helped. bt
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