350cui Chevy V8 Bored .030 over (355cui)
Holley Street Avenger 670CFM Carb (electric choke)
Edelbrock Performer RPM Intake
GM Performance Vortec heads w threaded rockers studs and guide plates installed
COMP Camps XE262H-10 "Xtreme Energy" hydraulic flat tappet cam. 218/224 dur @ 0.050, .462/.469 lift, 110 deg LS
MSD 6AL Ignition Box
MSD Probillet 8361 Distributor
Headman Shorty Headers
Optima Red Top Battery
Under 30k on the bottom end, around 5k on the top end.

 

Should be able to get 325HP out of that.

 

325 horses my back side, that should get you past 375 crankshaft horses.

 

That's a pretty mild cam.
If the moon lines up right, 375HP might be possible, but everyone (just about everyone) seems to be disappointed with their dyno results, so I didn't want him to be disappointed when he shows 309HP on the chassis dyno for example.

 

People seem to forget they lose HP to the alternator, power steering and water pump. Plus you lose 1% for each 250' of elevation, plus you lose 1% for each 10 degrees F above 60 degrees F, plus even if you use synthetic lubes, a T5 trans and 7.625" axle will eat at least 13%, or a 700R-4 trans and a 7.625" axle will eat at least 22%.
Without all those corrections, his combo should reach 400 horses.

 

the guy selling the motor finally replied and said it put out 238 hp and 310 torque through a 700r4 and 7.5 10 bolt in an s10

 

I also agree with Sonix, 325-340 HP is about all that combo is worth.

 

That cam, unmolested Vortec heads, RPMAirGa and 1.625" long tubes, I've seen 415 crank HP, standard correction to 60 degrees F, dry air, 29.92 barometer, sea level. And if you do anything to increase the line pressure in a 700R-4, or use an aftermarket torque converter (or both) it will eat closer to 30 percent.

 

And no telling about the mufflers the guy might've been choking it with. That 415 was with a pair of 2.5" Hooker Maximum Flows, which are not very quiet.

 

This bothered me all night. Here's what I wish to add. The FastBurn 385 uses heads that don't actually outflow the vortec heads, and it uses the ZZ4 cam, which is smaller than the OPs cam, and by virtue of such comparison this puts the OP above 385 HP. Also, the 415 I saw was without the HP loss of a power steering pump, an alternator and a non-electric water pump. Which puts us back around 390-400 HP.

 

one key component that the o.p. left out is static compression ratio. what is it? with decent compression I can see it possible to get in the upper 300's.