> First of all, why would you want to use the
> dished pistons? With the flattops and the
> N47, the cr will be less than 9.5 to 1. This
> is what Nissan should have done!!! Well,
> they had to contend w/somg laws. ****!!!
> The '83 block you have is identical to the
> '77 block, except for the flattops and some
> sturctural changes in the block's casting.
> There will be no modification needed to put
> the N47 head on this block. If I were you, I
> would bolt the two together and reap the
> benefits of the slightly higher cr. If you
> use the dished pistons, the cr will be a
> lowly 8.3:1. Thats great if you were going
> to turbo it. If not, use the flattops. Plus,
> you won't have to go through that hassle of
> tearing down a perfectly good shortblock.
> Here is another reason to use the flattop
> pistons. The flattops will provide a better
> squish in the combustion
> chamber. This promotes better, cleaner, more
> complete combustion. You will also notice
> more power. The dish pistons will not be
> able to compete in this area. Also, the cr
> will not be so high that you won't be able
> to use pump gas in it. You may even be able
> to use 89 octane. I think you should
> reconsider and use the flattops. Have I made
> this clear???? Good Luck!!!!
> Ian
Thanks for the words of advice Ian.
From th beginning i wanted to use the flat tops,
And a page that i read it said compression would
be about 10.4 which im sure would cause pinging.
Im not even concerned with smog laws there are ways around that here in Chicago.But i am concerned with valve clearances when using
flat tops with the small chambered N47.After all i am very reeeev happy i would hate to have a problem with that.After reading your re i`m happy to tell you that you have influenced my decision
greatly.But i`m still going to tear down the
shortblock to rering,freeze plugs,bearings,and
to further my piece of mind i`m also having
everything professionaly balanced.Of course the flat tops too. Thanks again for your help
i will keep postin my progress.PLease feel free
to give any other tips i may need.
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