i wondering if any one here can give me a ballpark of how much hp my motor will make this is my first post here so here is what im working with.

98 vortec 5.7 350
holley 750 DP
1.5 roller rockers
062 head rebuilt to work with my cam
LUNATI 54756 hyd. roller 232/242 @ .050" .510/.525,
headman long tube headers 3inch pipes with a x pipe
bullet race mufflers, world t-5 ,
MSD 6AL

 

If your compression ratio is the same, heads weren't milled, pistons weren't changed, I would say your carb will add about 5 cam 25-35, headers 25, exhaust 10 6AL maybe 5, and roller rockers add on average 10% Idk what intake you're using, I'd recommend an edelbrock performer RPM airgap, which will add between 5 -10. then you add all of that to the stock 250 and you come out at about 350-365, the add ons would be gross hp though. if you would take the gross power rating of your vortec engine it would be about 275-280 so you add the add-ons you're at about 375-390 at the flywheel. If you take off the 15% for water pump and alternator and PS pump then the 20% for a 700R4 you're at 255-265 at the wheels. I would recommend also getting some new pistons and upping the CR to about 10:1 or higher.

I'm at 10.4:1 with a similar combo in a '70 bottom end out of a camaro SS new spring and valves and a comp cams cam. I am making just over 410 hp and 420 ft/lbs of torque at the flywheel.

I wish you the best of luck with your project.

 

The GMPP 350 HO Vortec crate engine ( # 12486041) is rated 330Hp with a .212/222 ,435/.460 flat tappet cam
600cfm carb and a dual plane intake

http://www.sallee-chevrolet.com/Chev...ckV8s/330.html

Swapping in a 224/230 .470/ .480 flat tappet cam, a Air gap manifold and 1.5 roller rockers adds another 50 Hp

 

Guy on drag boards has the comp 236/242 cam in his vortec headed stock bottom 350 sbc with carbed dual plane intake and went 11.7's i believe with alot of stall and lot of rpm . Thats 320-330 whp my guess at his weight based on another car i know doin same thing

You are probably close to 300-320 at the tire if tuned right an have a good intake manifold

 

updated my info for every one.


98 vortec 5.7 350
stock pistons, stock stroke scat crank
holley 750 DP
airgap intake
arrowspace electric water pump.
1.5 roller rockers
062 head rebuilt to work with my cam not milled.
LUNATI 54756 hyd. roller 232/242 @ .050" .510/.525,
headman long tube headers 3inch pipes with a x pipe
bullet race mufflers, world t-5 tranny with a centerforce clutch , 3.73 posi 26x10.5 slicks
MSD 6AL
1 wire alt.
no power steering yet . plans to spray a 100 shot max.

 

You're probably in the 375-400fwhp range. Hard to get past that with Vortecs... you're getting real close to their limits, but it should pull real nice.