OLDS Olds 425 trans?

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CleanCutty86

Not-quite-so-new-guy
Mar 15, 2020
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No verdrive needed. Planned on a sbc but leaning towards rebuilding a 425. Already have a new th350 but guessing thats not going to hold up to it? Plans are to port and polish the original C heads and do a cam job and rods. Still running my 200r4 now. Possibly rebuild it. New to all this so kinda in the dark. Hoping to achieve plus or minus 400hp
 
Oct 14, 2008
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Melville,Saskatchewan
What was done to the TH350? You can get 400 HP pretty easy. Cutlassefi brought a nice 10cc dish Mahle forged piston with a 1mm ring pack. Along better rods and the right cam, it will haul *ss. The 2004R will probably need a billet forward drum.
 
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DRIVEN

Geezer
Apr 25, 2009
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*CENSORED*
I'll be having a purpose built 200-4r behind mine.
 
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CleanCutty86

Not-quite-so-new-guy
Mar 15, 2020
15
33
13
What was done to the TH350? You can get 400 HP pretty easy. Cutlassefi brought a nice 10cc dish Mahle forged piston with a 1mm ring pack. Along better rods and the right cam, it will haul *ss. The 2004R will probably need a billet forward drum.
Nothing was done to the th350 it is a TCI Street rodder New in the box
 

fleming442

Captain Tenneal
Dec 26, 2013
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Is there a drawback to a steel crank?
If being able to zing it as high as the heads will flow is a drawback, then, yes. Otherwise, get the lightest rods and pistons you can find, the wind the tach all the way around.
 
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Oct 14, 2008
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As fleming442 said, it is the most desirable factory crank that exists in any number. Get the aftermarket 7" rods along with the new Mahle piston and go to town. Make sure you run the right bearing clearance. The large 2.5" and 3" journals need more clearance than a SB. There is an argument between Olds experts where that number should be. You can definitely run tighter clearance with aftermarket rods than factory ones. I assume mostly street driven? Also make sure you have a good radiator, a large 2 core is a good idea along with either a 6 or 7 blade clutch fan or high output electric ones.
 
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