Say you had a low compression cast crank ext. balance 440 you were putting in a bracket car. You want to put some decent flattops in it so it had more compression. Keeping the stock rods. Would you need to stay w/ a heavy Speed Pro "Six Pack" piston or could you use (what I'm assuming is slightly lighter) Wiseco Pro True Street piston?

Anyone know a ball park weight of a stock slug vs. either of these two options?
How much lighter before it HAS to be balanced?

I usually balance all my stuff w/o question, but this is a real budget buildup.

What I do with small blocks is find out what the oem bobweight is/was. Then find all the weights of the oem parts and then you can look at approx weights of the parts your wanting to use and fiddle faddle to get them to that bobweight.

You can make or loose weight easily with wrist pin changes and removing extra rod weight weather the beams or the heavy weight on the rod cap.

You can loose 3-4 grams off the big end of the rod by using like a king Al bearing vs a std clevite.

You can get some weight from the piston and if I need the lower rod weight and ive one rods that even like six grams off vs removing six grams from the seven rod caps I run a bead on the bottom of the cap and clean it up.

But really if its a low rpm budget build, ive found you can get a decent balance job for under 200 if you mix and match things so they just need to remove weight.

As for how much you can be off, meh, many have mixed thoughts but one thing you can do on your own to help is make each rod/piston combo dead on the same.

Maybe not so much the BB stuff but ive found it semi easy to find the all the oem weights for a certain motor/year on the web.

Thanks EV2! I've found the "six pack" pistons are very close to the stock 440 piston weight at around 870 grams. Haven't been able to find a weight on the Wisecos yet.
This is a "beginner" engine for a friend of mine's son who wants to get started in racing. Just a hydraulic cammed 440 w/ a set of home ported cast iron heads, Holley SD intake, 830 holley, etc. Going in a fairly light (gutted) Dakota truck.
If it was mine, I'd probably just re-ring it and use the stock pistons since the motor runs great like it is now in bone stock form.

Later down the road when he gets some experience, they'll likely stroke it and get some good heads for it.

I got a set of the Speed Pro in one of my 440's, ran it with stock rods and didn't balance it. It was with a forged crank, not sure if that makes a difference. Didn't seem to hurt anything and ran okay (shifted at 6000, didn't turn over 6200)

I was researching the Weisco pistons awhile back and didn't have any luck finding weights on them, but did email Hughes about P/N:PTS531A3 and they said they weight Piston 546.50, Pin 220.39.

DusterKid...thanks! Sounds like the Wisecos are gonna be too light to not balance it.