454 bracketry clearance

ericcarr2000

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Mar 19, 2010
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903
I will be replacing my tired out ole 454 in my 1990 sundancer with a built 454. The question I have is if there is anyone out there that replaced their 454 and if they had any issues with regards to the factory brackets that attach to the carb base. I do have a hi rise intake but I also have roller rocker arms so I purchased a set of 1/2" valve cover spacers to be able to clear the roller rockers. I'm concerned with the shifting brackets coming into contact with the valve covers.
If anyone has encountered this please let me know. I'm pretty sure the brackets I'm referring to are on the starboard side of the engine.
 

Bondo

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Apr 17, 2002
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Ayuh,.... The only way to know for S u r e, is to put it together, 'n see,.....

Do the extended valve covers clear the exhaust manifolds,..??
That's usually a very tight spot,....
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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Merc 425hp 454's had crane cams roller rockers from the factory under cast stock valve covers. They also came with a wiend intake. Maybe check to see which bracket they used
 

alldodge

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Mar 8, 2009
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Valve covers were different in 88-91 then 92-96
In 96-97 roller cam
Exhaust elbow are the same from 88-97, (bulletin in 92-96) maybe further didn't check
Carb linkage same from 88-96, change to stamped steel after but basically the same
Shift bracket all the same

Is see there may be an issue with a bit of interference with the valve cover because newer versions have the cover angled. I would place the exhaust to head and see if there is clearance for shift bracket and valve cover. If shift bracket is an issue could use a plate like EMI uses

valve cover.jpg
 
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