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#1
03-21-2017, 09:33 PM
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Converting to RA III
Hi guys I have a 69 Firebird 350 that I'm converting to RA III manifolds which means I'll need new holes drilled and tapped in my head since my old log manifolds we're only 4 bolt. Does anyone have any tips and tricks to making sure the holes stay straight and don't go too deep or do you think I should just pay a machine shop and hope they get it right?
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#2
03-21-2017, 10:15 PM
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If the heads are off have a shop do them.Tom
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#3
03-21-2017, 10:27 PM
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Pay a machine shop.
You really can't drill them too deep, the outer exhaust bolt holes all intersect the head bolt holes on factory drilled heads.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
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#4
03-22-2017, 12:05 AM
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why modify heads?
there are adapters for this scenario.
__________________
1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
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#5
03-22-2017, 08:53 AM
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Alright that's what I was leaning just wondering if there was anyone that has done it and if it was rather easy or what. And as far as the brackets all the ones I've seen only work for certain heads but if you happened to know of ones that'll work on 47 heads with the large pad area and wanted to share a link that'd be awesome.
Thanks guys! |
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#6
03-22-2017, 11:38 AM
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aren't #47 heads 1969 castings?
if so i believe they should have all the bosses in place can you share a picture to be sure you even need anything? typically the heads missing exhaust bolt bosses are 1972 castings which generally have an alpha-numeric casting number; eg: 7K3
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1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
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#7
03-22-2017, 11:41 AM
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also, i believe the 1968/1969 GTO RA manifolds have privisions for five of the six exhaust manifold bolts - those might be worth looking into as well.
__________________
1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
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#8
03-22-2017, 06:26 PM
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Yes they are 69 castings I pulled manifolds last weekend and only had the four holes previously used but I'll clean them off and get a better look. Maybe I can share a picture if I get there this weekend.
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#9
03-22-2017, 09:43 PM
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those heads should have all six exhaust manifold bolt bosses.
All the 1971 & prior casting s I have seen had all six bosses. *crosses fingers that you find you need nothing*
__________________
1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
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#10
03-22-2017, 10:54 PM
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Well let's hope you're right! I didn't study them too hard but at first glance didn't seem they were there. Itd be nice if I don't have to pull the heads!
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#11
03-23-2017, 02:27 PM
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well poop.
it looks like I might be wrong. I did a search just now and saw these;  But those would be easy enough to drill and tap as the boss is there... and if you get the rights RA manifolds, your can just use the inside bolts.
__________________
1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
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