I have one month to build my engine so I was hoping I could get some suggestions on a 331. I am listing what I have below. My goal is to make a little over 400hp which maybe is not even possible. I am planning on driving it as a daily driver but gonna take it to the track regularly with a couple buddies. I have the crank already and it was balanced. Should I have had it balanced with the harmonic balancer and flexplace or can I just add those on later? 302 Roller block, 1pc rear main seal SRS flat top pistons 1.175/4.030/.912/-4.0cc CNC forged steel rods 5.400/2.123/.912/.833, full float Cast crank 3.250 331-2.248/2.123/5.4 Cam Roller-F .542/.563 224/232 (112) Rocker Arms-Stud Mount F/SB-1.6 x 3/8-LW AFR 1420 heads 61cc (according to them I would be at 10.10 compression) Lifters-hydraulic roller Pushrod 4130-.080 wall 5/16 dia.-6.300 long hydraulic roller spider retrofit kit
give the machine shop all the rotating parts and have it all balanced as a unit.The shop needs the crank/ pistons/pins/rods W/ fasteners so they get the bob weight correct,as well as the balancer and flywheel/flexplate.
Well... you need to know if you have a large bell housing or a small one. Large will require 164 tooth Small will require 157 tooth Either way your engine will require the 58 OZ imbalance damper/flexplate combo I am pretty sure your stock trans is a small bell unit but dont quote me on it.
later 302s (i.e. roller blocks) had a 50oz imbalance... i dont know about strokers... maybe it does take another 8ozs
My mistake...50 OZ is correct for 85 and up 302's not 58 OZ.perhaps 28 OZ for the engine in your car now...Unless the crank you had balanced was balanced for 28 OZ...Then...yeah 28 OZ is the way to go.Sumpin jus seems fishy though about the whole 28 OZ balance on a one piece seal crankshaft...I dont see that being correct.
the imbalance doesnt depend on the block. it depends on the crank. so what the crank is set up for is what you need.
Nearly all strokers are balanced to 28oz/ln. My 331 is. Makes no difference as to the block type. You've got basically the same build as mine, except mine has Canfield heads that are the equivalent of AFR165's and my cam is a Z303. Got tons of bottom end and pulls to 7000 with a dual plane intake. Went to a local car show Saturday and left afterwards in the company of a local cop (we're next door neighbors) with him in his 67 Impala. At every redlight I could break the 295/50's loose with a light powerbraking.
I'm gonna take my rotating assembly in to CHP today and I'll see what they say. I haven't figured out which flexplate I need but hopefully they'll help me out.
