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So I acquired a 427 BBC. Casting number 3935439 with 3917125 heads. From what I hear these are NOT to be run with unleaded fuel. Is this right? Will an adative work? I hear it's worth some $$$. How much? Anything else I should know about this engine. It's been bored .100 with KB 454 pistons. 454 steel crank. Completely balanced. Just anything else I should know would be appreciated.
 

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So I acquired a 427 BBC. Casting number 3935439 with 3917125 heads. From what I hear these are NOT to be run with unleaded fuel. Is this right? Will an adative work? I hear it's worth some $$$. How much? Anything else I should know about this engine. It's been bored .100 with KB 454 pistons. 454 steel crank. Completely balanced. Just anything else I should know would be appreciated.
its nolonger a 427 its a 470 only worth what someone is willing to pay may be 2500.00
 

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A buddy of mine bought a boat with a 460 in it and the seat dropped and you know the rest of the story, upon inspection these where not stock but put in by an unknown machine shop. Might have been crappy machine work but I just run a little additive and haven't seen any prob's yet.
 

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This was a big debate in the classic cycle arena. There were all sorts of people worried about this in Britain a few years ago, when they got away from leaded fuels. In the end, it made no difference. What was found, is that over time, the seats will actually become hardened due to repeated heat cycles. I've ran a lot of HIPO 60's hardware and haven't had problems. This includes plenty of V-8's as well as bikes.



Darrell.
 

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steelcomp was here
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A buddy of mine bought a boat with a 460 in it and the seat dropped and you know the rest of the story, upon inspection these where not stock but put in by an unknown machine shop. Might have been crappy machine work but I just run a little additive and haven't seen any prob's yet.
I've seen plenty of heads with the seats no longer in their bore, but 99% of the time it was something else that went wrong and the seat got beat up and came out and got blamed for the problem. Not saying it can't hppen, just that it's more of a myth than fact. Fact is, seats seldom just drop out.
Just FYI.:)hand
 

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I've seen plenty of heads with the seats no longer in their bore, but 99% of the time it was something else that went wrong and the seat got beat up and came out and got blamed for the problem. Not saying it can't hppen, just that it's more of a myth than fact. Fact is, seats seldom just drop out.
Just FYI.:)hand
i have a set of old #077 alum bowtie heads that are soft that have let a seat drop out,had brad anderson seats put in and since then i had one turn in it's bore about 45 degrees had it replaced but i need to have heads reheat treated or what i have heard is maybe cryo treat might be better?any thoughts???
 

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Listen to what the man said. Steelcomp is right seats just dont fall out if the seat was put in correct in the first place. Old fuel,poor quality fuel,wrong timing ?
 

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Bostick Racing Engines
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I have yet to see a head where the seat just plain 'ol dropped out.
I would have to agree in about 99.9 percent of the time it's either poor installation or "something" caused it to come out... except...

had an issue a few... perhaps 10 years now with Alexander seats "falling" out of heads... but it was only larger dia intake sized seats... like three sets of heads done at the same time. Turns out the seats has a prosity problem... you could take a brand new seat and drop it on the floor and one out of ten would instad of a "ding" it would go "dunk"... pick it up and it would have a crack in it... take a pair of pliers and it would just snap in half and sure enough... little air pocket inside. Needless to say we never used them again... especially since the company refused to accept any possible blame and assured us that it was our fault for the failure.:)sphss Ate 3 engines right up... and boy that was expensive to swallow.

Sure... anicdotal exception...
 
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