What would a reasonable safe boosted HP limitation be for a stock 360 cast crank ?

Do Magnum cranks have any hp limitation differences over traditional 360 LA cranks?

Curious about using a cast crank in a small single turbo street/strip application.
360 buildup would be very similar to the mild combo that topfueldart has with his turbo 318.
topfueldart combo

PT6776SP, .96 AR turbo or something similar.

I am not looking for ridiculous horsepower but would anticipate that it would be seeing 10-15 psi of boost and in the neighborhood of 500-550+ hp

Fairly realistic numbers given 4500 ft elevation and tuning.

Plausible or ticking time-bomb?

I know the most sensible thing to do is go forged...just curious about the el cheapo first option.
topfueldart's 318

Generally a cast crank is a no-no.
A little boost won't hurt it (5 to 10).
Detonation and Excessive rpm is what kills most cranks.

Engine probably wouldn't ever see more than 6000-6500 max rpm.

Go for it! How much HP are you waiting !?

Stock block doesn't usually withstand much more than 500HP, kinda weak at the pan rail & webbing.

If I could get an honest 500+hp (550hp would be great) on pump gas at my 4500ft elevation, I would be very satisfied.

I don't know if there is a difference in the old la 360 cranks and the mags but we tried to brake a mild LA 360 build with 125 hp No2 and couldn't , we sprayed this poor pup to death and it lived , I figure the total HP with the spray was around 500 to 525 and rpms were 6500 to 7k max floating all the way, stock rods with arp bolts, ext ball cast crank strait from the junk yard It was fun

500HP on a turbo 360 build will last for a VERY long time...

On one condition...

NO DETONATION!

There are 100's if not 1,000's of 500hp 360 N/A around the country that have been built.

Doing it with boost is generally easier on parts then doing in N/A. But if you get into detonation, that's when the cast crank will show it's teeth.

In general the cast cranks are more brittle then forged cranks. The forged cranks can take more shock (detonation) then the cast stuff can.

Be safe with timing, run good fuel, and watch the boost.

My Dad's Volare weighed 3890lbs this week. 340" with mild ported '308 casting heads, and a .550" solid cam went low 11's this weekend at the CC with 12lbs of boost... That's a very easy 500hp (probably more like 550hp+)

Good luck!

Are turbo motors as elevation-DA sensitive as Naturally Aspirated motors?

3% per 1000ft penalty.

For example 500hp at sea level sure isn't 500hp at 4500ft... instant 15% 75hp loss...now 425hp. 550hp is reduced to 467, ect.