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Discussion Starter #1
Ive been running a 436 cu in, for some time now, naturally aspirated, im considering playing with nitrous, I have a 4" crank with 6" rods now, would it be best to keep the crank and change the rods or just change rods, i have opportunity to buy some 5.850 rods now, my deck height is 8.99.
So 4" crank 5.850 rods, custom pistons Or keep the 6" rods and what ever crank and custom pistons ?
 

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Will your current crank counterweights clear the bottom of the piston near BDC with a shorter 5.85" rod??
A lot of 6" rod cranks won't, and it may cost you more than it is worth to turn the counterweights smaller for clearance and then have add a bunch of mallory back in to get the needed balance weight back.
Might be better to get the right crank to start with and just sell off your entire current rotating assembly as-is.
 

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Or maybe sell the short block and then the heads and build a true NOS engine that will not give you any trouble.
 

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X2. I’d say it depends on how much n2o you’re planning on and the rest of your combo. If it’s a lower compression street deal and you’re only planning on smaller shots (100-150 or so ), you could probably run what you have. If you’re planning on bigger hits (250+), then going with the shorter rod and a better piston makes more sense. Just my opinion.
 

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How much nitrous? If you're not planning on going over 150-ish, about anything will work just fine. If you want to push it harder than that, the shorter rod will allow for a taller top ring land. This will better handle the heat.

My advice is to stay with what you have for now, and see how you like nitrous, and get use to it at the lower power levels. Once you know a little bit about what you're doing, you can build a new engine that suits the power level you are shooting for.

Good Luck
 

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Discussion Starter #11
Will your current crank counterweights clear the bottom of the piston near BDC with a shorter 5.85" rod??
A lot of 6" rod cranks won't, and it may cost you more than it is worth to turn the counterweights smaller for clearance and then have add a bunch of mallory back in to get the needed balance weight back.
Might be better to get the right crank to start with and just sell off your entire current rotating assembly as-is.
I was told it wont, I have Simmons Machine here in South carolina is saying they can balance the new rods with crank.
 
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