i have the 350 in the machince shop getting built as we speak so now time for the extra costs i didt think about before building a 383.. i already bought a new tourque convertor 2400stall like my engine shop suggested, if i under stand it right i need a 400 harmanic balancer and a new flywheel??? can you guys try to help me and get it straight what i still need to buy

 

You need a 400 crank, and I assume you know you need to machine it to accept the extra stroke. Im not %100 sure but I dont think you need a harmonic balancer or flywheel, those are unrelated parts.

 

No need
You just buy a off the shelf SBC crank with a 3.750 stroke to suit your block style; 1 or 2 pce RMS that is a drop in fit
http://www.summitracing.com/parts/ESP-103503750/
http://www.summitracing.com/parts/ESP-103523750/

 

If doing a full rebuild the only extra cost is the cost of the new stroker crankshaft ( offset by the cost you would have paid to recondition your old crank)
and some labor to clearance the block for the stroker crank
Obviously you need 383 pistons but ( assumes engine needed boring OS ) you would have been paying for new 350 pistons at the same cost anyway

May be able to reuse your existing flywheel and balancer depending on which stroker crank you buy
If crank info states " requires 400 flywheel and balancer " like this one
http://www.summitracing.com/parts/ESP-103523750/
then you need new parts