con rod's
 

Whats up guys im lookin to put together a budget 383.i see some kits with 5.7 rod an 6.0 rods,what are the pros an cons of either one

Sorry no help with the rod question

But call a machine shop and ask them a price on machining your block, so there is enough clearance. Its pretty pricey i hear. With alot of grinding to be done. Thats just if you are on a budget

i think a longer rod puts the connecting pin up higher in the piston, i think you might burn more oil, since its so close to the oil control rings not sure though???

Not much difference in power if any, since your piston compression height will make up for the diffference anyway. Main reason for 6" rods is they are easier on the cylinder walls and better for longevity of an engine, but not as good for high revs.

Block machining for rod clearances is not that expensive, less than $100 usually, unless you have to clearance the rods for the cam, but not usually, unless its a 396. Youll pay a lot more for the line bore/hone.

Thanks anyone else.Where are you hign tech guys chime in

General consensus is that a longer rod/stroke ratio is better for (very) high rpm operation because of lower piston acceleration. This allows the piston to "dwell" near TDC longer and increases cylinder pressure (=hp). This piston/rod combo is also a bit lighter with the long rod combo. There is also less side loading on the clinder wall, which decreases wear and friction. But the magnitude of the difference is small.

With a stroker you also run into the issue of allowing enough room for the ring package. The wirst pin will necessarily be higher up in the piston with the longer rod. For NA, this is not an issue. But for blower or N2O setups you need enough room for a thick top ringland. I would sum it up by saying that for an NA motor a 6" rod is a good choice. For power adder, the 5.7" is better The faster acceleration of the piston away from TDC with a short rod also makes a power adder setup less prone to detonation, as it lower peak cylinder pressure.

Rich Krause

When I built my 383, I didn't want the wrist pin up in the bottom of the oil rings (my preference), but I wanted a relatively lightweight package, so I opted for 5.850 rods. This places the pin location JUST below the oil control rings, and gives me a little more meat up top (N2O motor) and still allowed me to use off the shelf parts (scat + JE). Saved a little weight too, without getting into an unreasonable rod ratio.

Just another view...

Dave C.

Yeah, 5.850" is a good compromise.

Rich Krause

thanks guys for the info.