Snowman,

I did not have a turbocharged 250 but had a planitary ball driven Paxton supercharged 250 daily driver & only made 8-9 , rarely close to 10 tops psi of boost pressure.
Blowing though 3 DCOE's (more even fuel/air distribution)
Pic on stand w/out webers ,sold them on Ebay actually sold it all on Ebay.


Non lump port head,but had my custom upper lumps installed.

Stock rods, side grinded,polished,shot peened,w/ARP bolts,SBC 307 forged flat top pistons.,nothing special really.

4:10 rear gears,2800 brake stall converter, (not fun on freeway BTW)

Never dynoed it or even raced that combo @ a track, but I did race it against my friends 66 Nova w/a SBC 350 which he ran at a race track on a regular basis.
He later installed a built 406 w/Dart pro heads,etc,etc,etc & then he ran 11.3's-11.7's depending on tires he had used.
I thought that was too fast for me to race my little 6, LOL

My friend wanted to race me right after he got back from a race track running consistant 12.70's w/his semi built 355 CI.

We lined up right outside of my friends work so his co-workers could see the race, (Little Ceasers pizza).

We raced & I beat him by 4 car lengths, he was upset & his friends were shocked.

I later raced him @ a dfferent location w/the same results.

I estimated my combo made approx 400 HP & would run the 1/4 mile about 12.4-12.8 range on any given day.

I know,, not a rock solid comparision as a track or dyno would be ,so take it for what it worth to you.

As far as dyno comparisions go,unless you run the same dyno, same opperator,,they are not a really good comparision to anything else, just bragging rights & a good way to tune your ride & be safe instead of trying to tune on the street.

Take my Syclone 4.3 ,262 CI engine for a comparision , a little bit bigger engine ( 4" bore helps a lot though )stock they make 280 HP & (360 FT LBS of torque IIRC)
That is with running 14 psi of boost pressure.
The camshaft is anemic & the heads flow worse than our siamesed port head.

I had installed a larger turbo (flowed 100 CFM more), not much bigger than stock , believe me. I made the intecooler more efficient, MSD6A box, a Aquamist 1S systm & a stiffer wastegate.
Adjustable fuel pressure reg, cold air intake 3" exhaust , straight through type muffler, ran the boost up to 21 PSI dynoed it on a Dynopak dyno http://www.dynopak.com/

My Syclone made 386 HP & 550 ft lbs of torque.

Same dyno, same day, same friend (66 Nova guy) but with my old 65 SS Malibu, he built a 406 SBC 9.8:1 aftermarket aluminum Edelbrock heads2.02 int. 1.60 ex, headers,dual plane RPM airgap manifold,headers,dual 2.5" exhaust,Camshaft was approx .550 lift, 230's degrees duration @ .050
His Malibu made 370 HP & 460- 470 ft lbs of torque.
He also ran that @ LACR track 2800+ altitude & ran 13.0 @ 108 MPH
spinning the 275-45-17 radial tires for quite a ways, like 2.1-2.2 60 ft times.

Just an FYI, the Syclone engine is really nothing special as a long block, it's basically a Chevy Astro van engine w/lower compression ( Hypereutectic pistons )the pistons blow apart very quickly when the Syclone & Typoon engines detonate, & I mean right away.

I also made pulls @ 17-21 psi of boost. Looking foor dyno sheets as I type. aaaaarrrrrhh!

So,in short,, you can make quite a bit of power from the 250, you just need the correct supporting parts to do so safely & reliably.

Keep the interest going, you can do it.


MBHD

12 port SDS EFI