Any guesses on HP for this 403

[Mike T]

All I have ever done is SBC and a little bit with the Pontiac 400 & 389. So i don't know squat the doodle about your rig.
I'll need:
Bore
Stroke
Rod Length
How far the pistons are in the hole. (ths)
Piston valve relief in cc
Piston dome in cc (probably none)
Compressed gasket thickness
Head chamber size (cc)
Intake & exhaust valve size
Head type (23 degree wedge??)
Rocker ratio (1.5 - 1?)
Intake runner size, in cc
Exhaust runner size in cc
Type of exhaust. (Stock or headers & pipes)
Exhaust pipe size.
Carburetor make & size (cfm)
Intake manifold. (Stock or after market)

I'm assuming from what I've read in your post, that the engine is mostly stock.
So I can go with some generic settings and get you pretty close.
However, the more detailed the input data, the more accurate the output will be.
I won't be back on till tomorrow night, so I won't get your specs until then.
I can run the numbers and have something for you the next day.

 

[Csilvy2000]

All I have ever done is SBC and a little bit with the Pontiac 400 & 389. So i don't know squat the doodle about your rig.
I'll need:
Bore
Stroke
Rod Length
How far the pistons are in the hole. (ths)
Piston valve relief in cc
Piston dome in cc (probably none)
Compressed gasket thickness
Head chamber size (cc)
Intake & exhaust valve size
Head type (23 degree wedge??)
Rocker ratio (1.5 - 1?)
Intake runner size, in cc
Exhaust runner size in cc
Type of exhaust. (Stock or headers & pipes)
Exhaust pipe size.
Carburetor make & size (cfm)
Intake manifold. (Stock or after market)

I'm assuming from what I've read in your post, that the engine is mostly stock.
So I can go with some generic settings and get you pretty close.
However, the more detailed the input data, the more accurate the output will be.
I won't be back on till tomorrow night, so I won't get your specs until then.
I can run the numbers and have something for you the next day.

I can get all those specs. I'm in no hurry, just take your time. I'll send you the list in the next few hours.

 

[olds307 and 403]

I think my nearly indentical build showed 215 hp according to 1/8 mile mph. Only difference was shorty headers and a 2400 stall converter. With the 2.29 gears, it will hurt your times a lot. Also with 84+cc chambers, you will have high 7's compression at best. Pick up a pair of early 350 heads, you will be around 9 to 1 compression and gain a way better exhaust port.

 

[Csilvy2000]

The early heads along with the aftermarket pistons seem to be the hot ticket to pulling power out of this engine. My hang up was, by the time I located and purchased a set, then had them rebuilt with the 2 inch intake valve, might as well spent the money putting together a 400 hp SBC. So I used what I had and tried to maximize my build. Besides, opening the hood on an Oldsmobile and seeing an 'Oldsmobile' just kind of seems 'right.' I meant to say, install the 1.625 exhaust valve.

 

[L92 OLDS]

With 84+cc chambers, you will have high 7's compression at best. Pick up a pair of early 350 heads, you will be around 9 to 1 compression and gain a way better exhaust port.

This^^^^

The factory 4A heads have huge chambers. I stuck $1,200 into set of 1968 #5's which made a big improvement. Stainless 455 valves, hardened seats, etc. Final compression ratio was 9.4 : 1

 

[DROLDS84]

220hp-285tq...my guess

 

[Csilvy2000]

All I have ever done is SBC and a little bit with the Pontiac 400 & 389. So i don't know squat the doodle about your rig.
I'll need:
Bore
Stroke
Rod Length
How far the pistons are in the hole. (ths)
Piston valve relief in cc
Piston dome in cc (probably none)
Compressed gasket thickness
Head chamber size (cc)
Intake & exhaust valve size
Head type (23 degree wedge??)
Rocker ratio (1.5 - 1?)
Intake runner size, in cc
Exhaust runner size in cc
Type of exhaust. (Stock or headers & pipes)
Exhaust pipe size.
Carburetor make & size (cfm)
Intake manifold. (Stock or after market)

I'm assuming from what I've read in your post, that the engine is mostly stock.
So I can go with some generic settings and get you pretty close.
However, the more detailed the input data, the more accurate the output will be.
I won't be back on till tomorrow night, so I won't get your specs until then.
I can run the numbers and have something for you the next day.

Got all my numbers wrote down. Went off and left them at the house. I'll post them up tonight after work.

 

[Csilvy2000]

I think my nearly indentical build showed 215 hp according to 1/8 mile mph. Only difference was shorty headers and a 2400 stall converter. With the 2.29 gears, it will hurt your times a lot. Also with 84+cc chambers, you will have high 7's compression at best. Pick up a pair of early 350 heads, you will be around 9 to 1 compression and gain a way better exhaust port.

So did you ever put it through the full quarter mile. Just going by the way mine feels, I'm guessing low 15's in the quarter. Car weighs about 3400 lbs., has a 27.8 inch tire. Car does great cruising at 70 on the highway.

 

[pontiacgp]

are you going to get it dyno'd or are you going to take the highest estimate and claim that?

 

[Csilvy2000]

are you going to get it dyno'd or are you going to take the highest estimate and claim that?

I'll take the highest estimate, then add some Summit Racing stickers to the back glass. Maybe add another 25 horsepower. Then tell everyone it dyno'ed at that.