I have a 5.7 liter truck block with a four bolt main. I wanted to know if this is externally balanced.

 

no SBC, except the 400, was externally balanced, don't get confused, or let someone confuse you, about the bat wing weight on the flywheel

 

But my cousin's boss' brother's ex-wife's husband's mistress knows a guy who was told by another guy who heard it read from the internet that...

 

 

I forgot to mention it's a 383 stroker, that would help.

 

if you used a 400 crank it is more than likely externally balanced

 

1986 and up one piece rear seal crankshafts technicly are externaly balanced. they had to have weight placed on the flywheel/flexplate due to the fact that there is no counterweight on the rear of the crank.

 

technicly(sic) all SBCs, except the 400, are internally balanced, reguardless of what you read on the internet.

 

if all 86 and up cranks are internaly balanced then you should be able to use a 1955-1985 flywheel/flexplate(that has no weight) on them with no balancing issues correct? if this is in fact correct, then yes, all sbc minus the 400 are internaly balanced. but you and i know this can not be done. so considering that the 86 and up crank needs a weighted flywheel/flexplate to maintain balance, and said flywheel/flexplate is externaly located, then i would have to conclude that the 86 and up crank in all one piece rear seal blocks are externally balanced. if you can give me some evidence that this is not the case( more evidence than "regaurdless of what you read on the internet"-quite a ignorant statement considering i learned this from working on rather than reading about engines), then i would gladly accept this otherwise illogical staement.

 

All SBCs except the 400 are internally balanced. The fact that a tiny amount of the total weight is located on the dry side of the rear main seal, and that since the crank flange can't accommodate it it has to be located on the flywheel instead of on the crank flange like earlier internally balanced motors had it, doesn't make it externally balanced. The entire balance weight required to counterbalance each of the 4 journals is evenly split on each side of the journal, which makes it "internally balanced", even though some of the weight LOOKS external to the untrained eye.

None of which has anything to do with whether a 383 is internally or externally balanced.

This same guy posted this twice, and it's already been answered in the other post. The answer is of course, that only his machinist knows for sure how he built it; and we can argue a bunch of stupid crap all day long (again.... it just won't go away) on the Internet, and none of it makes the slightest bit of difference toward helping this guy out, because we didn't build the motor.

So, unless some one of us is the guy that built his motor, we can't help him any more than he's already been helped.

 

I didn't put the motor together otherwise I wouldn't be asking. Thanks for the replies

 

neither did my machinist

 

Ask the guy who did. He's the only one that has any chance of knowing. If he can't tell you, nobody can; least of all, any of us.

 

i don't actually work on any engines, everything i know comes from reading stuff o nthe internet from mr. vaders and RBs post and for a good laugh a little of what RD post.