Factory block strength

[fekbmax]

427 block, .010 over, completely square decked on head, oil rails, timing and water pump, and bell housing, deburred, Throughly cleaned water jackets for maximum adhesion of hard block block fill, filled to 1" below deck. Billet program main caps,(all 5), line bored, studded and girdled, . Fully race prepped block.
So with everything done as close to perfect as possible such as parts combo and balance, how much normally aspirated HP would this block handle. ?
1/8th mile drag, 2600lb car.

How about after cryogenically treated ?

[blykins]

867.3.

I'm being facetious of course, but I would expect it to be pretty stout.  Maybe Blair has pushed one that hard, but I normally go aftermarket instead of taking a chance on killing a valuable factory piece. 

Also depends on rpms, how much weight you're slinging around in the crankcase, etc.

On your other thread about the crankshaft, it would depend on the bobweight, but I'm usually adding lots of metal.  Cutting the counterweights down means that you have to add more metal. 

[CaptCobrajet]

I have a few early top oiler combos floating around the planet with lots of runs on them at around 800 with no block filler.  Paquet ran the Ford blocks for many years at 800-ish power, filled, etc.  I have a sleeved down 427 at 4.200 filled that has about 1000 passes on it with the OEM caps, that made 700 or so for the first 500  passes, and 750-ish for the last 500 passes.  Not uncommon for Ray's to see near 9000, and my Cobra Jet rig saw 8500 in good air, but the parts were light, and the balance was right.  The fuel was also always "good".  That last sentence should be in caps because I believe that many blown engines and main bearing issues are a result of undetected detonation from old or "sour" fuel, or the wrong fuel.

With all that said, I think 800 hp is a safe place to quit on a NA early block(top oiler with 2-bolt motor mounts).  The sideoilers are thinner.  They make good 390s with sleeves.  The BBMs are so thick in the deck and cylinders, and the mains are much beefier....... nowadays, I wouldn't think of big power without using a BBM block.  We did what we did with the Ford blocks when we had to, but now, for the same money, the new block is a no-brainer. JMO.

[machoneman]

Between 1,500 and 1,850 hp at 9,000 rpm with a basic 90% nitro load, 60 degrees or so in the mag, and about a 30-35% GMC 6-71 blower overdrive. Not quite what you were looking for but.........

Basically, the old T/F and F/C SOHC stock bore, stock stroke fueler engines of yore. But......they often only ran 3-4 times, and then on lower nitro loads like 60%-70%, before the bottom end cracked up through the cam tunnel area. Ed Pink, noted SOHC Ford engine builder, said the same often that he needed a much stronger OEM iron block back then.

If one wonders about where all those Cammers in the famed Holman-Moody warehouse picture went, many were wasted winning lots of nitro races where FoMoCo essentially gave many away to 'factory' racers, legion were their numbers long ago.

https://www.enginelabs.com/features/interviews/the-old-master-ed-pink-reflects-on-sohc-irl-and-midget-engines/

[fekbmax]

Thanks guys, its 2 separate builds, wanted to make that clear. The 391 crank is for a budget blower build using alot of good pieces laying around, it's mostly a pro street type deal. Looking for the cool factor in a 73 pinto .

The block deal is mine and I need to get rolling on it. It's a really nice 427 center oiler marine block in real good condition. 
I'd love a bbm, I'd trade my tunnel port heads and intake and the marine block for a BBM or even one of the good geniuses pieces but yeah, no one is intrested.