403 Block with 350 crank?
December 28th, 2018, 05:35 PM
#1
Rodney
Thread Starter
Join Date: Jun 2011
Location: Houston, TX
Posts: 2,317
403 Block with 350 crank?
Can a 350 crank be used in a 403 engine build using the stock 403 rods & pistons? I know the 350 crank will physically fit in the 403 block, but will it need to be rebalanced for the heavier 403 pistons?
December 31st, 2018, 07:51 PM
#5
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Join Date: Aug 2005
Location: Braceville, Ohio
Posts: 1,972
Is something wrong with the original 403 crankshaft? Imo, the 350 crankshaft isn't an upgrade. The only upgrade would be a 330 forged crankshaft that would require the 330 harmonic balancer and 330/early 400 flexplate.
January 1st, 2019, 06:11 AM
#6
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Join Date: Nov 2008
Location: Central Fl
Posts: 7,824
Hmmmm not true. The 403 crank is the worst of the bunch, a true cast crank that’s quite spindly as well. Even a stock N 350 crank would be an upgrade.
January 1st, 2019, 10:56 AM
#7
Rodney
Thread Starter
Join Date: Jun 2011
Location: Houston, TX
Posts: 2,317
Kenny:
I bought 2 403 blocks several years back when I was still contemplating the my engine options. Both blocks are std bore and came with 2 complete sets of stock rods & pistons, one very rusty 403 crank and a good condition 350 N crank. The 403 crank had been left in the weather and was too rusty to save so I sold it to a guy that builds furniture with engine parts. He planned to sand blast the rusty crank and use it to make an end table for a TransAm guy. I really need the space so I'm trying to sell the rest of these parts. I didn't want to give out bad info on using the 350 crank in the 403 block so I checked in with the CO crowd. I wonder if you built the 403 with lighter rods and pistons would you still need to add metal to the crank to get it to balance?
I bought 2 403 blocks several years back when I was still contemplating the my engine options. Both blocks are std bore and came with 2 complete sets of stock rods & pistons, one very rusty 403 crank and a good condition 350 N crank. The 403 crank had been left in the weather and was too rusty to save so I sold it to a guy that builds furniture with engine parts. He planned to sand blast the rusty crank and use it to make an end table for a TransAm guy. I really need the space so I'm trying to sell the rest of these parts. I didn't want to give out bad info on using the 350 crank in the 403 block so I checked in with the CO crowd. I wonder if you built the 403 with lighter rods and pistons would you still need to add metal to the crank to get it to balance?
January 1st, 2019, 11:12 AM
#8
Registered User
Join Date: Nov 2008
Location: Central Fl
Posts: 7,824
Using the different rods and pistons saved over 300gr on the bobweight. Pretty significant I’d say.
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