[Johnny406]

With a progressive nitrous controller starting at 20% to 100% from .5 seconds to 2.0 seconds, can a factory cast 428 crank consistently and repeatedly take a 250-300 shot of nitrous?

Block would be a bottom filled .030 over factory 4 bolt with factory caps, ARP studs and long dowel pins. Venolia flat top blower pistons, BBC 6.660 H-beam rods.

[mgarblik]

Not exactly comparable, but a reference point? We ran 3 1971-1973 455 stock blocks converted to 5 billet Program Engineering main caps. Ran stock, race prepared "N" crankshafts ground with maximum fillet radius to 2.200" Aluminum BME connecting rods. Ran as much as 350 HP plate big shot nitrous at times. Then converted to Plate and port combination at around 400-450 HP eventually running upper and lower foggers in the 500 HP range on the stock blocks. HP was in the 1200 HP range. Never broke a "N" crankshaft. Did eventually break all three blocks in the same place, up the #2 oil feed hole all the way to the camshaft tunnel. One block broke at both the #2 and #4 oil feed holes up to the cam. We ran our blocks open, no concrete. With 1/8 mile long burnouts and long run times, we needed the cooling. Not sure if this is helpful or not. My 2 tidbits of advice would be: 1. Get your rotating weight as light as possible, aluminum rods a must for heavy nitrous loads. 2. Retard your timing more than you think is possibly correct. Best of luck with your heavy hitter.

[KS circutguy]

I ran 200-300 shot system Custom made spray bar by John "Nitrous" Gosson for 20 yrs.
Pontiac 400 stock reconditioned rods TRW Forged pistons stock crank resized 6X heads comp 280 cam,Qjet built by me, 1978 400 block 2 bolt mains (the thin cast one).
Ran that block for 5 yrs. hundreds of street strip passes on and off bottle.
Finally split the block inside on the main webs.(Known weak area of the late castings).

Next build was early 70's block (thick casting) 2 bolt mains.main studs,head studs,Cometic head gaskets.
Ross custom flat tops Eagle H bean pontiac rods,custom Ultradyne solid lifter nitrous cam same 6X heads as before but fully ported by me.
Dual plane Edelbrock manifold, same Qjet.
Ran 4 -6 yrs. till I refreshed motor and sold car.
Ran a bottle heater,dedicated nitrous fuel system located in factory battery location, 2 gallons Jegs fuel cell with its own Carter 17 psi race pump and regulator.Ran race 110 fuel in it and 92 in main fuel tank.Was my daily driver as the 1st build was.
I miss it, won't lie.