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#1
02-25-2014, 10:24 AM
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head to block allignment
Last night while installing my 6X heads on my 421 block we noticed the bolts do not want to start in the block, the heads sit in the dial pins perfectly. anybody ever have this problem? could I drill out the head a few thousands to leave the dial pins move in the head and let the bolts do the allignment? thanks for looking jd grim 66 gto
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#2
02-25-2014, 12:30 PM
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Could be that the heads have been angle milled, on propose or by accident. Or the deck is way out of square to the crank main bore.
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Bull Nose Formula-461, 6x-4, Q-jet, HEI, TH400, 8.5 3.08, superslowjunk Last edited by Blued and Painted; 02-25-2014 at 12:54 PM. |
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#3
02-25-2014, 12:51 PM
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I would resist the temptation to drill anything out. You would be treating the symptom and not the cause. Take time to find out what is wrong.
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#4
02-25-2014, 02:34 PM
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Quote:
Were the block and heads decked? If not, that is where I would start. The dowel pins would be removed in order to deck the block, ask the machine shop to replace them. .
__________________
. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
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#5
02-27-2014, 12:25 AM
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Were the block threads chased with a slight chamfer added to the bolt holes? Might be all that's needed.
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon in progress. |
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#6
02-27-2014, 01:35 AM
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Quote:
Only the dowel pins can locate the heads on the block deck in the correct location. The head bolts can't be used to locate the head, they can only clamp it to the block |
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#7
02-27-2014, 08:51 AM
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Very good point on the chamfer, though would THINK that most machine shops do that when milling.
.
__________________
. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
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#8
03-07-2014, 11:05 PM
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head to block allignment
I think I'm ok now, after talking to Butler who did the heads and to alot of people smarter then me everyone agreed that drilling out the head bolts would not hurt anything and give me the clearance I needed to install the head bolts. Did this on a Bridge-port using a 9/16" drill bit, both heads set perfect on the block and intake sets perfect also, all bolts go in with no clearance problem, thanks everyone for your imput. jd grim 66 gto, 421 40 over, 6X heads tri power, all roller, soon to get this old guy in trouble.
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