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Discussion Starter #1
I got asked? (I need a new crank,can I use a 305 cast crank in my 350 engine?)
yes the 305 crank can be used,BUT..the 305 crank is ballanced differantly and has slightly differant counter weights, the damper and timing marks may differ on some combos, and the 305 crank is not designed to ballance correctly with the rest of the 350s rotating assembly, and it possiable that youll need a differant damper and flex plate, youll need to reballance the assembly at a minimum if your interested in high rpm ,high performance use!
since youll more than likely need to get the total rotateing assembly reballanced anyway and that if you use lighter weight aftermaket pistons and rods the crank should be fine as far as ballance goes,(after the ballance job) but also remember that cast pistons, stock rods and a cast crank like that 305 cast crank are not the best choice if your thinking about 6500rpm plus engine rpm ranges as a standard application
now keep in mind a good ballance job costs about $150-$200 so what will you be saving? and why are you not building a 383 (3.75" stroke) or 396 (3.875" stroke) short block? if your building an engine and need to buy pistons and a crank anyway...?



http://www.rdspeed.com/rotating%20kits.htm

http://www.hotrod.com/techarticles/79478/

http://www.prewittracing.com/newpage2.htm

http://store.summitracing.com/partdetail.asp?part=SUM-CSUM383KIT&view=257

http://www.bracketmasters.com/small_block_stroker_383_cu.htm

http://www.allchevyengines.com/383-350.htm


262 = 3.671" x 3.10" (Gen. I, 5.7" rod)
265 = 3.750" x 3.00" ('55-'57 Gen.I, 5.7" rod)
265 = 3.750" x 3.00" ('94-'96 Gen.II, 4.3 liter V-8 "L99", 5.94" rod)
267 = 3.500" x 3.48" (Gen.I, 5.7" rod)
283 = 3.875" x 3.00" (Gen.I, 5.7" rod)
293 = 3.780" x 3.27" ('99-later, Gen.III, "LR4" 4.8 Liter Vortec, 6.278" rod)
302 = 4.000" x 3.00" (Gen.I, 5.7" rod)
305 = 3.740" x 3.48" (Gen.I, 5.7" rod)
307 = 3.875" x 3.25" (Gen.I, 5.7" rod)
325 = 3.780" x 3.622" ('99-later, Gen.III, "LM7" 5.3 Liter Vortec, 6.098" rod)
327 = 4.000" x 3.25" (Gen.I, 5.7" rod)
346 = 3.900" x 3.622" ('97-later, Gen.III, "LS1", 6.098" rod)
350 = 4.000" x 3.48" (Gen.I, 5.7" rod)
350 = 4.000" x 3.48" ('96-'01, Gen. I, Vortec, 5.7" rod)
350 = 3.900" x 3.66" ('89-'95, "LT5", in "ZR1" Corvette 32-valve DOHC, 5.74" rod)
364 = 4.000" x 3.622" ('99-later, Gen.III, "LQ4" 6.0 Liter Vortec, 6.098" rod)
383 = 4.000" x 3.80" ('00, "HT 383", Gen.I truck crate motor) (5.7" rod)
400 = 4.125" x 3.75" (Gen.I, 5.565" rod)

Two common, non-factory smallblock combinations:

377 = 4.155" x 3.48" (5.7" or 6.00" rod)
400 block and a 350 crank with "spacer" main bearings
383 = 4.030" x 3.76" (5.565" or 5.7" or 6.0" rod)
350 block and a 400 crank, main bearing crank journals
cut to 350 size
 

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Grumpy you Rock
The only thing I can add is if you use the old Z28 302 crank, GM made this for only a couple of years in the late 1960s and there were two different cranks (forged) the main bearing diameter was larger on the last year they were made. GM had a 425 HP option back then with 2x4s, what a Bad 302 from factory.:thumbsup:
 

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Discussion Starter #3 (Edited)
btw I got this question on the 383 stroke kits?

"Grump, what does an average balance cost now a days?"

it depends on how far out of ballance the combo your useing is and whether its internally ballanced or externally ballanced, but Id say the average is at about $190 for the job,the differance between internally ballanced or externally ballanced,is that on internally ballanced cranks the crank ballance center (with bob weights matching the rods & pistons)and central axis match, on an externally ballanced crank the crank is significantly out of ballance (with bob weights matching the rods & pistons) but the damper and flexplate have large weights added at the correct location on their perimeter to allow the combined combo of the cranks total rotateing assembly to now match the central axis and ballance.
both will work! but the internal ballance crank is under less stress and normally puts less stress on the bearings and block, and is the prefered combo

heres several sources
http://www.performancemarket.com/cranks.htm

look under
http://www.flatlanderracing.com
(stroker kits)
(chevy smallblock)
(383)
I would advise useing a CAST STEEL not CAST IRON crank thats INTERNALLY BALLANCED if your costs are to be kept at a minimum or forged steel if your looking for max strength, so you can use your current 350s damper and flexplate,and 7/16" rod bolt(H) style rods to gain a significant advantage in both clearance in the block and strength in the rods

they are significantly stronger and require much less grinding on the block than stock style rods like these, and normally don,t require a small base cam like the (I) style rods might,over the 3/8" bolt stock rods like these
 

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A FORGED STEEL crank would have LESS FLEX under load(slicks) A CAST STEEL crank is stronger than a cast iron but nothing but a FORGED STEEL for me. :thumbsup:
 

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Discussion Starter #5 (Edited)
while your correct that forged is stronger, I have yet to see a cast steel crank that was properly ballanced fail. the rods , (particularly the rod bolts)and pistons (normally due to detonation or a failed valve train) fail first in almost all engines, and before they fail the valve train normally becomes a problem, now that being said, I also run a FORGED STEEL CRANK, simply because I want the most strength I can get at a reasonable cost.
 

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The reason Grumpy has not SEEN a cast steel crank break must be he did not work at a Drag Strip as I have. Grumpy is correct with his opinion about cast steel cranks as long as you DO NOT use Racing SLICKS, GO for it if you are running STREET tires. Grumpy I am NOT slaming you just pointing out from what I saw while working at Green Valley Drag Strip from 1969-1971. Good information on crank and rod sizes.:thumbsup:
 

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Discussion Starter #8
LAB ?

I don,t count a CRANK as having failed if a rod or the valve train failed FIRST, if that happends the crank may be forced into trying to compress a valve or force a broken rod out of or thru the cylinder head
since cranks were never intended to do that a failure under that condition is not something Id count as a crank failure.


have you ever seen a properly ballance cast steel crank fail that did NOT also have a busted rod or rod bolt or broken valves??
 
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