building 289/302

I'm getting ready to build a warmed over 289 and going to put 302 rods/pistons/crank in it . I do not intend to drag it just like it to go when I floor it . A friend of mine brought home a set of digital scales from work and below is what I found. All weights are in lbs.
Rod Weights
TE206 1.189
TE360 1.188
TE480 1.186
TE478 1.186
TE429 1.186
TE200 1.186
TE203 1.186
TE275 1.187

Piston Weights
A 1.702
B 1.707
C 1.702
D 1.700
E 1.699
F 1.700
G 1.706
H 1.702
Rod+ Piston Weight

TE206 + E 2.888
TE360 + D 2.888
TE275 + F 2.887
TE480 + A 2.888
TE478 + C 2.888
TE429 + H 2.888
TE200 + B 2.893
TE203 + G 2.892
I have been debating on getting things balanced but after seeing this I'm not sure I really need to . Input welcome and Thanks .

Have them balanced and the crank,flywheel and damper all together. Cheap insurance even on the street.

For balancing purposes each rod is measured twice, the big end and the small end is measured separately to calculate bob weight. You don't mention if you're using stock or aftermarket parts. Stock crank, rods and pistons, I wouldn't worry about balancing. If anything is non-stock get the assembly balanced.

Normal measurements are done in grams to be more precise. It's good that the parts are all close - but that's really not very helpful. You need a rod weighing fixture to measure both the big end and the small end. Also, when you take it to a shop their scale may not be calibrated like your scale, so they'll do it all over again anyway.

You measure all components separately - pin, piston, rod ends, bearing, rings. Add an allowance for oil, then take 100% of the rotating weight (big end items) and 50% of the reciprocating weight (small end items) to get the bob weight. The crank is then spun on a $25,000+ machine with the bob weight attached to the crank pins to determine if the counter weights match the bob weight.

As mentioned, if you're using stock replacement parts, you should be OK. If you have any performance parts in there - forged pistons, aftermarket rods, etc - get it balanced.

As ckelly said, the rods/pins/pistons need balanced to the bobweight of the crank. It's good that they are all consistent already, but that's not the -main- point of the balance job.

The balance shop will make them all consistent down to around a gram (the weight of two extra strength Tylenol pills) then drill the crank counterweights in the right places to balance the crank/rods/pistons to the crank.

You will want to take EVERY part of the rotating assembly with you to the shop when you go... Harmonic dampner, crank, rods, pistons, pins, rings, flywheel/flexplate, clutch pressure plate.... and some will even take the crank pulley.

Good Luck!