How much power is your buddy shooting to make? IMO, anything less than 900-1000hp, stock caps w/ arp's should be fine. I agree 100% with crank flex causing the caps to walk and fail, I have lots of SBF experience with that. The stock Nailhead crank is fantastic, you would spend $1000+ for a modern forging to equal it. What I would do, though, is fill the water jackets up to the bottom of the freeze plugs and just do a build on a 401 block w/ minimal overbore(I like thick bores for boost builds). Also, an Innovators West dampner would be worth it too. Stocks rods w/ arp's and polished beams should also be ok at that level, or go H beam and reduce the journal to 2.10. I think there is a lot of power in camming the combo right, might take some experimenting. If you need pistons, contact me, I did a thin ring 401 build a while back that would be perfect for what you are doing.
Thanks for the info guys I will pass this info on. I agree the stock crank should be fine. The fellow building this engine is interested in extra re enforcements but in this case it may just cause more complication and cost. Regarding the aftermarket crank, cast custom cranks are too time consuming to make leaving billet as the only real option. king cranks did my custom 350 billet crank and it was $3000 all said and done after I paid the R&D costs.
Who said anything about a cast crank as a custom? A run of un-machined BBM forgings would probably fit the bill.
I think that's come up here before. The bore centers of those engines is close enough to consider, and I can't recall what I thought it would take to make happen when I looked at it a long time back. Grab yourself a 383 crank and set it in a block to see where it's at. I'm not thinking of it as an 'if', but more of a 'what's it take' to make happen kind of thing and the reality of having to finance this endeavor is what keeps me from finding details. Not to sound rude or anything...if you want to see it in your hands or discuss pertinent details, let's come up with a marketing plan and production run estimate. Obviously, one at a time would succumb to the billet's custom nature for similar costs.
Contact Crower, TA has them make there Tomahawk forged cranks from the BBM raw forgings and the Nailhead has the same bore spacing as the BBB so would be as simple as just turning the mains down from 3.00" to 2.500", the thrust is very similar as well. OR if he is really interested in making everything a bit stronger, there are bearings that are for 2.750" main journals that would be a nice fit in a Nailhead block with the right line boring done to it. The larger main journal would give the crank more overlap to help strengthen it if it is a test the limits type of build. PM me if you want the part # for the bearings.
Hi again, I use to work at a company that made injection mold hot runner systems, and they would cut 3-4 thick piece of steel with a water jet, funny thing was they would run it overnight and ever now and then the nozzle would clog and would result un a few inches of water accross the shop floor in the morning. Regards,