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MOP
01-26-2005, 07:52 PM
Not being very knowledgeable about this stuff, but being deeply caught up in it I have been trying to find out what are the benefits of the 6" stroker kit I have, hard to get a straight answer. Many said more torque but stroke is stroke the rod length does not increase leverage so what does it do.
The post was an answer to a post on the 6" rod issue and a little more, like what is a Turtle! I grabbed it as it seems to be a decent answer with a little extra, figured I would stick it up here and see what some of you think.

Phil

You most likely won't feel much of a difference. The longer rod will decrease load thrusted into the cylinder wall due to a decrease in rod angularity, which will reduce frictional losses and bore wear. So basically you're engine can flow to higher RPM's and will be more durable while doing it. The Rod length to Stroke Ratio (R/L) determines the angularity of the con. rod and having a 1.72:1 R/L ratio (assuming your crank's stroke is 3.48") is excellent. Increasing the con. rod length optimizes maximum power from the reduction of friction. What are you're intentions for the engine as far as street or strip, (low-mid peak torque or high end power). Lower R/L ratios don't really decrease power for engines running most of their life under 3000 RPM. Which is why the torque monster small-blocks 383, 406, 420 and even 468 made for great low end tire smokers. With their longer strokes and larger bores they had a major increase in low end power but were endanger of failure at high-rpms, from the lack of con rod length due to the 9.025 deck height of the small-block, so their R/L's were crazy low. Depending on the compression height of you're pistons you might have clearance problems with the 6" rods given the 9.025" deck height. To establish a proper zero deck compression height for you're pistons add half of the stroke and the length of the rod and subtract from 9.025. You might also run into con. rod bolt clearance problems with the oil pan rail and camshaft. The crankshaft, con. rods, and pistons normally run hand in hand, modifying one necessitates modifying the other. And as far as the 850 cfm carb goes, that large of a carb will affect your idle and throttle response if your engine is running under 500 hp. The other day I
was reading an article in CHP (Chevy High Performance), and they were comparing different cfm rated carbs on an engine that put out roughly 450 hp at peak. The comparison showed that 850 cfm carbs weren't necessary and/or efficient in an engine less than 500 peak hp. While the 650 made for excellent throttle response and power right off of idle it had limited mid-high power, the 750 cfm gave the most optimal performance for the engine. But I don't think they used a turtle :-/. The 2" spacer can help depending on what RPM range you are looking at. An open plenum spacer will improve high RPM performance but will decrease low end power and 4-hole spacers will improve throttle response for street driven cars. You might want to experiment with a combo of both. The turtle takes the spacer a step further designed specifically for an individual intake manifold to direct air and fuel for improved mixture distribution.

Drewnashty