383 Street Engine / balancing issue
 

Hi,
I want to fit two 383 Street Engines ( crate blueprint) in my boat. I know i Need to change the Cam and the Core plugs, but what Happens with the crank balancing ? All Engines are Balanced external. ( flexplate/ balancer) if l Take now my existing balancer and flywheel the balancing is gone.. What is to do? Or is it a misunderstanding on my side?

Thanks for your help

Daniel

Why not spend the extra money for Blueprint's marine engines?

Are the new engines internal or external balance ? You probably want to run stainless head gaskets.

you could buy 400 small block clutch flywheels. repros are pretty cheap. can still find orig ones on ebay-craigs. but truly blueprinted motors are balanced to that wheel, not a generic standard. so, unless you already own these street motors, it doesn't make sense. but if you are using stuff you already have and don't wanna send motors back to be torn down and rebalanced, that would be the way to go. use the balancers that are on the 383's and buy the flywheels.

boats 74: I will spend the extra money but I need the alloy heads to lower the wheight..

dereknkathy: thanks for the help. I`m not sure why Blueprint did not add the parts to the engines if they sell it... The balancer could be find in web but I cannot find a flywheel.. :-(
They advice "This engine requires a 400ci weighted harmonic balancer, and late 350ci weighted flexplate/flywheel."

they are mistaken on the flywheel. look on ebay. put 400 chevy clutch flywheel in the search block.

350's are typically externally balanced. 400's are typically internally balanced.

When going the stroker route (using the 400 crank) it reverts to an internally balanced assembly. You can either buy a 400 flywheel OR have somebody mill the weights off the 350 flywheel.

balancing
 

My personal experience with the mentioned manufacturer. I had a customer buy two marine 383s received them installed and experienced a vibration on both engines I called the manufacturer and asked what components the customer should use. The answer was suprising to me "I don't know we take the crankshafts out of the box and install them we don't balance them" the person I spoke to identified him as the owner of the company and there was no one else in the technicall department.

Let me explain something to help put this in perspective for people who buy mail order engines. When you buy a balanced rotating assembly and it doesn't include a balancer and flywheel you are not buying a balanced assembly, the components that are bolted to the crankshaft can not be assumed to be balanced, they must be balanced as an assembly and don't let any one tell you you can take any component off of any engine and your balance will be fine this happens at least once a year on oso. The purchase of a marine or performance engine should researched carefully and the customer should visit the engine facility these purchases should never be made blind folded unless you have alot of time and money. Sincerely Laz Mesa
www.mesabalancing.com

That's backwards, 400 sbc is external, 350 is internal balance. A 383 can be either depending on what parts you use.

You are correct . I had stealth balancing done on the front of my stroker crank so i could run a 350ci harmonic ballancer
. Still had to run a 400ci flywheel and you can see they are weighted . They do have a weighted plate that slides over your rear crank bolts meant to be run with the 350ci flywheel but i didn't like that , it's still hangin on the garage wall .

That's what I meant. I had a moment of balance dyslexia.:drink:

I have that every now and again but it's alcohol induced . :ernaehrung004:

Me too, but I didn't have that excuse this time. :D

Hi,
I have an interally balanced 4340 steel crank ( scat) if this is done I need to use a flywheel which has no wheights. Is it right or did I have a misunderstanding?

Correct, If you have an internally balanced motor run a neutral balance flywheel and balancer(no weight).FWIW a 383could be either.