Could change the design of the piston and also the torque curve of the engine...

 

The longer rod will allow the piston to dwell slightly longer through TDC. This by itself will not result in power increases, but with the right camshaft design and a tunnel ram type manifold with significant plenum volume and long runners there may be some HP increases, especially at high RPM levels. The long rod will also reduce thrust friction on the cylinder walls and may allow a lighter piston. In summary a long rod can be beneficial, but only if the whole engine combination is designed for the log rod ratio.

 

6.385 rod = 1.290 compression height
6.535 rod = 1.140 compression height.

It all depends on your piston needs. This is based on the 9.800 deck height.

 

If you're planning on street driving it, keep in mind that a longer rod will shorten the skirts and create more piston rock within the bore. Not a big deal in race type engines that a serviced frequently, but could create a little extra wear and some ring instability over many thousands if miles if it's going to be a driver. It also tightens up and raises the ring package a bit, something to consider if you're thinking about nitrous.

 

What ru planning on using it for? Deck height? Nitrous?

 

Thanks for all the replys. Engine will be a N/A track only. 454 short deck block is being used.

 

6.385 is the rod you're gonna want.....