347 Hp Estimate?

You're going to need all of that and a lot of compression to get 450rwhp out of a 347. 450rwhp is a tall order. You can get to around 375-400 with just a better intake and a 205cc head and reuse your cam etc. It should peak in the 6-6300rpm range. If you're going to make a max effort stock block that's the direction I would use. If you went the solid cam/shaft rockers-225cc head, you would have to shift that at a very high rpm(72-7500+rpm). Stock blocks do not like high rpms and will eventually break.

You could just throw a small nitrous kit on and make 450 easy.

Another serious question:

Is it mainly the power that kills these blocks or the RPMs required to get to said power NA?

Just wondering how safe bumping up to 450 with nitrous would be. Because id imagine i would still be able to keep the RPMs below 6500 with a kit and get the job done that way


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The girdle on my stroker is so that, maybe, when my block splits I might be able to save the rotating assembly. Still wish I would've built a SHP block but..... you live and learn.
 
Guess it depends on how hard we run our motors. I'm in the process of going turbo 331 on a stock block. I know a couple guys that run decent power on stock blocks with no problems. In my defense I do have a Mexican block. Some say its the harmonics from high rpm runs. I won't be pushing mine like that. My trans will blow first....gotta have a t5 fuseable link. Lol
 
A girdle does nothing more than help hold your broken parts in the pan. On a stock block, I don't understand putting high dollar reciprocating parts in that are rated higher than the block.

Save up your money for high dollar crank, pistons when you get a Dart block.
 
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Rpms over 6500 and/or power levels around 450-500rwhp seems to be the accepted limits of the stock block. The block will live at those points but only for a limited time(really depends-some last a few years...some blow up fairly quick).
 
A girdle does nothing more than help hold your broken parts in the pan. On a stock block, I don't understand putting high dollar reciprocating parts in that are rated higher than the block.

Save up your money for high dollar crank, pistons when you get a Dart block.
Wish I got that advice a few years ago.