engine balance question

[shelbe67]

I have bought an angine from a buddy of mine he had it built for him and now i am putting it in my car My question is how do you know what its balanced for? its a 347 stroker I know most are balanced for 28oz but how do you know? I have the flywheel and balancer but now I am just curious

 

[D.Hearne]

If it's a 347 there's a 99% chance it's 28 oz/in.

 

[shelbe67]

thats what I thoughtbut when I asked my buddy if it was 50oz he said yes then gave m that deer caught in headlights look so I wana double check cuase I think its also 28oz but I really dont wana screw anything up

 

[D.Hearne]

Running with the wrong pieces won't hurt short term, it'll just shake its ass off. That'll tell you then you've got it wrong. Chances are though it's 28 oz though, very few will be done to 50.

 

[BarnStang]

Surely your buddy knows who built the engine? THey would know, but D. is right. WHat is the date code on the block above the starter? THat will tell you what year the block is. It would be unusual to turn a 50oz imbalance shortblock into a 28oz...if the balancer and flywheel are 28oz, you're probaby safe in assuming the shortblock is 28oz as well. At least 99% safe

 

[D.Hearne]

With strokers, all bets are off, most are 28 oz, regardless of block date. My 331's in a late 80's roller block and balanced to 28. The crank counterweights are bigger for the heavier rotating assembly, making it harder to balance to a 50 oz. The reason for the 50 oz was Ford's lightening of the cranks in the early 80's to save on production costs and rotational mass. So in short, the strokers are balanced to 28 by neccessity, not by block type.