[swoodard23]

What is my horsepower (flywheel and rwhp)?

1977 Corvette L48 stock bottom end

9.5-1 compression

Comp Cams 268h

Stock Vortec 906 castings with upgraded springs and machined for extra lift

True dual 2.5" exhaust without cats, magnaflow mufflers, ram horn manifolds

Stock 750cfm Q-jet carb

Edelbrock Performer RPM intake

Turbo 350 trans


Guesses?

Scott

[DoubleVision]

I ran your combo on my Virtual Dyno Program.
Peak Horse power is 285 at 4750 RPM
Peak Torque is 364 at 2500 RPM.

[swoodard23]

flywheel? I would have thought it much higher than that.
Scott

[NAIRB]

I would peg it around 350 horsepower if it's tuned right, with over 400 ft lbs of torque.

[Holder350]

you can drop 30 horses with a auto tranny, and 15-20 with a manual depending on the gear spaceing.

[fitzwell]

275 at the flywheel

on a chassis dyno, mebby 235-250

[killerformula]

I'd put you a little less than 300 at the flywheel, maybe 275 or so. The compression, intake and cam help a bit, but we're still looking at stocker heads and exhaust, along with a relatively mild cam.

This isn't bad considering what you're working with! Remember the 100% smogger 350's with 8.5:1 compression, smog heads, stock cams and exhaust were putting out 150-170 horse. You're a full 100 horse ahead of those motors!

K

[Jmark]

Atleast 50!

[swoodard23]

I found this article which looks almost identical to my set up with the exception that they spent 30minutes cleaning up the heads with a grinder and they got 384hp and 401lb-ft. http://www.chevyhiperformance.com/te..._iv/index.html
Same compression, cam, heads, and intake with a less restrictive exhaust. I can't imagine headers giving me 100hp.
Scott

[chevymastermind]

MY ENGINE::

350 4bolt main bored .030 to 355cid
steal crank (3.48" stroke)
Sealed power flat top -5cc flat top (9.5:1 comp. ratio)
Speed pro piston rings
Stock rods with Milodon chromoly Rod bolts
heads are chevy 333882 casting heads with a stage 2 port job
Manley Stainless steel valves 2.02int. 1.50 ex.
Comp cams roller tip rocker arms 1.6 ratio int. 1.5 ratio ex.
z-28 valve springs
Comp cams XE268 camshaft (same camshaft as you)
comp cams 84000 series lifters
Hooker headers and chambered exhaust

and on a Dyno (engine dyno-flywheel HP rating) my engine made 370.21HP @ 5662RPM and 409.1 Ft. Lbs. of tourque @ 3900RPM and it has over 400 Ft. Lbs. of tourque from 3,200-4,300 RPM!

i'd say put a aftermarket set of good flowing heads and headers on you car and a good intake manifold and you would make way more HP then you are now. or go the rought i went and bring your heads down to your local engine shop and get your heads ported! because the power band of your cam is just kicking in (2500) is right around when when your heads start flowing like crap (3500RPM)!

id put your hp at about 300-310

[DoubleVision]

He`s using Vortec heads which are the highest flowing factory head out there. Give them the correct port job and they will respond with quite a gain. When I ran his combo on the Dyno program, I used the flow chart for vortec heads.
When a engine is dyno`d for power on a gross rated dyno, it`s alot different than as in the vehicle, you have to add in the losses created by the alternator, water pump, fuel pump, fan, power steering pump, plus add in the drive train losses, after all those losses are accounted for, the number goes way down.

[chevymastermind]

Originally Posted by DoubleVision

He`s using Vortec heads which are the highest flowing factory head out there. Give them the correct port job and they will respond with quite a gain. When I ran his combo on the Dyno program, I used the flow chart for vortec heads.
When a engine is dyno`d for power on a gross rated dyno, it`s alot different than as in the vehicle, you have to add in the losses created by the alternator, water pump, fuel pump, fan, power steering pump, plus add in the drive train losses, after all those losses are accounted for, the number goes way down.

im not sure but im pretty sure vortecs flow better at low rpm? right?

[454C10]

Hard to fit a RPM intake under a vette hood. Do you have some kind of scope?

A 268H cam is not a ex268 cam. The 268H is 218/218 and around 0.460 lift with 110 lsa.

Headers could be hurting the power a lot. I would say at least 30hp with your setup. A set of block huggers would 1/2 the difference. Look on chevyhiperformance site. They did a story on headers. "What are headers worth?'. Yes, they lost 100hp versus stock log style manifolds but the test was done with a 292H cam (244/244 at 0.050). Your cam is much smaller and the rams horns are better than the logs so I'm thinking only a 30 or 40 hp loss.

340hp and 390 ftlbs would be my guess for crank power. I bet your car sounds good and runs strong and still gets fairly good mpg.

Any 1/4 mile runs???
with headers should be able to run 13.5's @ 103
without 13.8's at 100.
12.5's at 112 with 100hp of n20.

Dana 44 with 3.08 and a th400???

Don't worry about hp numbers so much. Are you happy with the power?

FYI, I like that 268H cam but it might be a little too big for a 3.08 gear. The 260H would feel stronger with a 3.08 and stock converter. The 268H works well with 3.40 to 3.55 gears and a 2000 stall. However, the 268H would work well with a 3.08 and 4 speed manual.

[lmsport]

The Vortec heads will out-hp a Dart 200 up to 400hp. The Bowtie Vortecs will go 460 hp. I have built an engine like yours with untouched Vortecs, roller rockers, dyno headers 1 3/4" and an Edelbrock Q-Jet and made 340hp.

[38Dodgebiz]

Less than 300. 275-285 sounds about right.