Code: Select all
5.7" rod 6.0" rod
stroke rod/stroke ratio rod/stroke ratio
3.00" 1.9:1
3.25" 1.738:1 1.846:1
3.48" 1.638:1 1.724:1
3.75" 1.52:1 1.6:1
Moderator: Team
Code: Select all
5.7" rod 6.0" rod
stroke rod/stroke ratio rod/stroke ratio
3.00" 1.9:1
3.25" 1.738:1 1.846:1
3.48" 1.638:1 1.724:1
3.75" 1.52:1 1.6:1
Or running a lower r/s ratio benefits a package that has too much port volume. All a matter of perspective...Stan Weiss wrote:Talking about rod length without stroke just adds another variable to the equation. I believe that an increase in rod/stroke ratio will help an engine that is under headed for its ci size / RPM range.
StanCode: Select all
5.7" rod 6.0" rod stroke rod/stroke ratio rod/stroke ratio 3.00" 1.9:1 3.25" 1.738:1 1.846:1 3.48" 1.638:1 1.724:1 3.75" 1.52:1 1.6:1
CNC BLOCKS wrote:It depends on the combination but rememeber that going from a 5.7 to 6.250 the engines is going to breath differently!!! And to optimize you can't run the same cam for both rod lenths.Old School wrote:What are the differences in the cams you use for a 5.7 rod compared to the 6 inch rod?
Believe it or not the out of the 4 different cams we tried in them the 6.125 and 5.85 made the most with the same crower 00432 cam,the 6.0 did best with an ultradyne and was the all around best of the 3 even though the 6.125 made a whopping 6 more hp . I wouldnt consider any of the stuff i build for myself calculated or optimized , more like screw it lets try it and see what happens.CNC BLOCKS wrote:Hopefully your not using the same cam for a short and long rod engines!Sprinter99 wrote:Over the last few years i've had 5.85 ,6.0 and 6.125 rods in 355s and the longest rod made the MOST power on the dyno but was SLOWEST on the track, the 5.85 made LESS peak power than both the other two but was MUCH faster off the corners than the 6.125. A big example of we dont race dynos.
I stopped reading when they said 400 block.The Dark Side of Will wrote:I've had a question about this for a while...
http://www.airflowresearch.com/articles ... /A3-P1.htm
What do you guys think of the engine in that article? Can you really run higher compression with longer rods? That is, of course assuming that quench, chamber/piston polishing and coatings are the same...
An engine like that could be built much more easily nowadays using 6.250 rods and shelf pistons for a 400 with 6" rods instead of the 6.209 Ford rods and custom pistons.
Good rod length/ratio info right there!new engine builder wrote:I stopped reading when they said 400 block.
The 400 sbc is the biggest P.O.S GM ever put out.
I have over twenty 400 blocks that have "rod windows" or holes in the lifter valley that sit all over the shop floor as a reminder of why we use what we use today.
Sure, they might live in a street car or a drag car for a few seconds at 7,500.
Try taking one down both the back stretch and the front stretch of a "tacked-up" dirt track only lifting engough to "set" the car for the corner on a large 1/2 mile track.
You might get 10 nights out of one or 10 seconds.
It's not a question of if, it's when.
Either use a Dart SHP block or an old 010 4-bolt block for a starting point.
x2Warp Speed wrote:Good rod length/ratio info right there!new engine builder wrote:I stopped reading when they said 400 block.
The 400 sbc is the biggest P.O.S GM ever put out.
I have over twenty 400 blocks that have "rod windows" or holes in the lifter valley that sit all over the shop floor as a reminder of why we use what we use today.
Sure, they might live in a street car or a drag car for a few seconds at 7,500.
Try taking one down both the back stretch and the front stretch of a "tacked-up" dirt track only lifting engough to "set" the car for the corner on a large 1/2 mile track.
You might get 10 nights out of one or 10 seconds.
It's not a question of if, it's when.
Either use a Dart SHP block or an old 010 4-bolt block for a starting point.