[RustyRedneck]

Hey guys, I'm always collecting parts for projects I'm working on or projects I have on the list for someday. In this case, I'm talking about both. I started on a 350 SBC for my pickup a while back and have been trying to figure out what parts I need before I get everything ordered. I had planned on this engine being pretty mild as my first automotive engine build. Hoping for 350-400 crankshaft horsepower. This fall, I was given an SBC 4 bolt main block with crank and pistons that had head studs and had been bored .060 over. I hadn't planned on using this block but figured I might keep the pistons around if I needed them or sell them to someone else. The block was laying upside down in the dirt in a leaky barn and was pretty rusty. The crank is forged and I'm guessing is a factory unit but haven't cleaned it up enough to find that out yet. My good, clean crank, that came out of my .040 over block that I had planned on using, is a cast crank. Now for the question. At what performance level or other requirements would you guys say a forged crank is required? I like the idea of using them whenever possible just for durability's sake. I also have available to me a 440 Chrysler Forged crank that ate a rod probably 30-40 years ago and has a pretty decent gouge in the no. 1 rod journal. The guy I'm getting it from, if I so choose, has offered me my choice of crankshafts for $100. Seems reasonable but his only Forged unit has a .125 gouge in the rod journal. I talked to Crankshaft supply in Minneapolis MN about it and they can weld it up but I'm wondering if I should just get a cast crank and save a little more money. In that engine project, I'll be putting a 440 crankshaft in a 400 block and I'm hoping for 650 crankshaft horsepower. If I remember correctly from reading about the 440 crank in a 400 that somebody else did, it required some clearancing in the block. Thanks in advance!

 

[BogiesAnnex1]

Forged cranks at least factory mild steel cranks bring good fatigue resistance and with a surface hardening treatment good wear resistance as well. These are the reasons those cranks find their way into heavier pickups and performance engines. The down side is if you have to turn the journals the hardening treatment is removed. The problem this causes is in rubbing type wear without surface hardening forged mild steel wears faster than nodular iron that is used in crank castings. The whole gambit is to move the surface wear onto the bearing inserts than on the crank journals.

For a 350 to 400 horse engine a nodular cast iron crank is plenty good.


Bogie

 

[cerial]

The 440 crank is worth messing with at that price.

A good cast sbc crank still covered in oil is worth $50 in my book. Forged only $100 more.
SBC parts are common enough you need to look at what a new one will cost vs the machine work and your time bringing a old one to the new ones specifications.