DURANGOKID59

I dropped a valve in my 454 mag carb, and am going to need a complete rebuild due to metal shaving throughout the motor from a broken spring and keeper, and bent the valve. Im thinking the most cost effective option is going to be stroke it to a 496 vs a new motor. What all need to be done to my 454 to get it to a 496, other than the obvious of oversized pistons and having the cylinders bored? Also, is there a website or does someone have a buildsheet of what is needed to do the rebuild? Im trying to do all this on a very tight budget because I have a baby on the way very soon. Thanks for the help in advance.

1BIGJIM

iTrader: (1)

tight budget and boating do not go well together
Just because you dropped a valve dosent mean your engine is trashed. If the crank is still good stay with what you have. Turn the crank, new pistons, rebuild the heads and be happy.
Save the money for diapers

I assume the moter stopped in it tracks when the valve dropped, how would you have metal shavings all over the engine?

DURANGOKID59

Yeah, I know they dont go well together, I realized that the first time I filled the tank, lol. I guess what I left out is that when I tore the heads off, there has been water in the cylinders before (just bought the boat 3 months ago) so the cylinder walls have a layer of rust on them. So Im thinking they'll have to be shaved anyway? So thats why Im thinking of bumping it to a 496.

DURANGOKID59

When the valve dropped the motor didnt quit, and ran a few more rotations, and bent the valve up in to the head, breaking the keeper, and spring. The inner spring was shredded basically, and I found chunks of it all over the cylinder head runners, so Im guessing there are shavings throughout the motor now.

SB

iTrader: (1)

Count on around $2500 for good quality rotating assembly.
Crank, rods, pistons, rings, etc.

$800-$1k crank
$500-$700 rods
$450-$700 pistons

Add in money for machine work and well, you know the drill.

Yes, well worth it if you can spare the $$ and want the added performance.

Could always get a new GM Marine 502 longblock. Just a thought.

DURANGOKID59

Thanks for the reply SB, do you happen to know of a good website for a parts list to get everything I need? I did a websearch, but Im only coming up with car/truck applications, and want to make sure I get the right stuff. Thanks

SB

iTrader: (1)

I'd talk to your engine builder about wants and needs first.

There are a plethora of internal parts available - from crap, to okay with some work, to real good with some work, to real good, to killer, to 'there's people that can afford this' stuff.

I posted prices of 'real good with some work'

SB

iTrader: (1)

BTW: you dropped a valve. Good possibility one head is junk or atleast a possibility of a lot of $$$ to redo.

Add cyl heads into 'worst case scenario.'

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I'd take a look at what you have now and then go forward with a real plan.

Or, if you are hiding behind the 'don't want to spend much $$' statement and really are willing to spend good money for a good motor - then let's forge forward.

Are you looking for a 450-500hp 496/502 or a 550-600hp 496/502.

DURANGOKID59

Thanks for the input SB. I think from here Im going to get the motor completly out of the boat, and get some quotes and go from there. I was just trying to get a good idea of what parts would be needed and kinda get a game plan going.

gofastlvr

Go check with Ken @ http://www.precisionengine.com/. He just built me a set of 468's that i just got in and ran a couple times but so far so good and they got delivered for around $4k each w/ a warranty for either 1 or 2 yrs - I'd have to look at my papework. I hope I don't have to!!

They run strong and I am very happy so far.

Buy the new and sell what's left of the old.

I've also got a basically stock 454/400hp engine w/ about 200 hrs if you are interested.