So I have a 1969 Olds Cutlass with the following, Crane 30 degree Cam

Edelbrock Performer Manifold

Edelbrock 650 series 4 Barrel carb

Moroso valve covers

MSN racing ignition

Hooker long tube heads

Dynaflow mufflers

Bored 30 over (new sleeves springs etc)
How do I find out the engines new HP?

 

The correct answer is always not enough. What block what engine

 

LOL true story its an Olds 403 from a 79 Pontiac Trans am

 

My guess would be 300 to 320 ish depending on all the variables.

 

Gotcha...nice looking car shame your not in Ohio I need body work lol

 

Thank you. It's all good. I actually don't do work on the side i mainly stick to collision work.

 

Put it on a dyno

 

Understood

 

If there was one by me I would / will when the weather warms up.

 

Unless the engine comes out and gets dynoed as installed, its a guesstimate to an educated guesstimate at best.

Most car guys mean flywheel net when talking HP. Wheel dyno will be the lowest rating. Well wrung out at the track can also give you a good idea of HP.

Without your cam specs hard for me to get a good guess in but you may appreciate this YouTube vid I am posting. Its a 69 Cutlass with a 403 and

" edelbrock performer rpm intake

625 edelbrock carburetor,

hooker super comp headers

2200 TORQUE CONVERTER

.030 bore, and 3.07 posi

Crane Cams "
(specifics are listed in description)

He is quite content with the improvement over the original 350. Looks like it is a supreme and likely had my same 310 HP Gross rated 350 with true dual exhaust and 40 series Flowmasters.

From 2:45 minutes on is the 350 being wrung out vs the 403. Then its all 403 from 6:30 minutes on. Sounds and moves great.


Below is the original 350 vid. It will help clarify how he put the comparison video together.

 

The honest answer is never enough!!

The only way to know for sure is a dyno turning session. How expensive depends on how picky you and the dyno operator want to be in finding the best tune.

If you do decide to put it on the rollers, make sure the car is ready. Know what the current timing, jetting, etc is, have some tuning parts on hand

 

My guess... more than you need, less than you want.

 

So piecing this together from multiple posts, you have:

403 bored .030 over, unknown compression ratio
Crane Cam, unknown lift and duration
Edelbrock Performer intake
650 cfm carb
full length headers

Maybe try to find out what pistons and camshaft were used in the build. You can't even get an output from a dyno program without that basic information.

 

200-250rwhp

 

At the risk of being a poopy party pooper, that’s a roughly 185 hp (net) engine in stock form. On the bright side it packs 320 ft/lbs of torque. So bump the number 15-20% on the hp for gross, then take 5-10% away for accessories.

Understood we don’t have much to go on but cam, headers & intake is not going to increase the hp 50-100%. I’m thinking 250-275 hp (gross), the drivability on the street should be decent with low end torque but I wouldn’t bet it increased any with the mods, likely just raised the sweet spot a little in the rpm range. With a bit of gear it would be a good driver.

All unsubstantiated voodoo math and wild *** guesses presented are the opinion of this writer only and should be given little credibility.

 

The absolutely most find way to get a guesstimate on power is to find out exactly what the car weighs. Is there a grain elevator or gravel pit place near you? Drive the car across the scales to an exact weight with driver. Then go to your nearest Dragstrip for a test and tune session. Once you have a timeslip with a mph number and the weight there are many online calculators that can figure hp based on mph.

Of course, once you run the car down the track, then you start looking for ways to improve the performance. It’s all downhill from there!!

 

The time slip is the only way imo where you can truly gauge the performance. The Dyno will tell you how much the engine it's self makes but the time slip will tell you how good your set up is

 

And the first thing would likely be replace the 650 cfm carb with something in the 750-ish fm range.

 

I kinda thought the same thing. However, the OP was asking about his engine in particular, and not advise on improvements.

I really wish those carb cfm calculators would disappear. Or that people would learn that the smallest Q-Jet made is capable of 750cfm. Of course, if more people knew that it would probably cut into new carb sales.

 

We have a winner, the drag strip, it gives you something quantitative. My similar spec 403 ran a 11.3 in the 1/8 the first run out, horrible! Going from 2.56 to 3.42 gained .6 in the 1/8. Also shorty headers and better exhaust also gained. I got it down to 9.7 in the 1/8 but still not great. I should have bought early heads and a bigger cam. Unless a smaller dish piston was used, you may be at 8 to 1 or less compression. My 4A heads CCed at 86, huge compression killer and the exhaust side of that head, isn't good. Pull a valve, if don't believe me, I did, not a free flowing port. Your small carb, if tuned right might be Ok, especially if it is the motor is the low compression variety. Hopefully you have a good cooling system as well, make sure it is before any long trips.

 

What you say makes a lot of sense actually, the fact of the matter is these engines (late 70s) come from a very bleak era for performance. Headers and true dual exhaust may give you 225 HP or so net on a stock healthy 403. That's loosely the equivalent of what a 69 Cutlass Supreme would of been rated at birth with single exhaust and manifolds. And 1969 Supremes are not performance cars, they are glorified grocery getters (optioned V8s rather than base line 6 cylinders).

180 hp in 1971 was 260 gross for 350.

Headers and true dual exhaust still fall in under gross number. 220 HP then add 5hp for the 403. Now give yourself a 20 HP bump for the new cam...

So now the 403 is 245 HP as installed flywheel net. This is a conservative (tight estimate) but realistic assessment where you won't disappoint yourself.

275 HP gross
245 HP net (headers and true dual exhaust)
200 HP at the wheels

P.S. A 3800 lb test weight with 245 HP net should see a 14.5 @ 94 MPH in the 1/4 mile with a good gear/set-up. That's 2 seconds and 11 mph faster than a factory stock 403 in a Trans Am could've dreamt to see. And 1 second and 3 mph faster than a factory 310 HP 69 Cutlass. Now your approaching W31 performance.

Money well spent.

And mine as well .

 

There's this show called "Engine Masters". Y'all should watch it.

 

Fleming engine masters is awesome but there is some things to consider. Their testing although very thorough can be a bit generic. Love it but have to take it with a grain of salt.

 

Well, it IS entertainment, afterall. I think it's interesting as all get out how the things they change show (or not) on the dyno. The header bash is probably the best example of that. The ignition system test was a complete fail, on the other hand.
My point was more to the effect of: you can't arbitrarily throw horsepower gains on part changes. It doesn't work that way. The only true test is the track.

 

Now I remember reading all the speed part ads in the magazines years ago, the ones claiming a 20hp increase with this part, 15 with that one, before long you have added 100hp without taking off a valve cover. Are you suggesting that we are LIED to?!

 

One of my favorites is the cooling fan comparison. People refuse to believe that a engine driven clutch fan is just along for the ride until the cooling is needed.

The oil pan/oil level test was an eye opener as well.

 

I know when the fan belt blew off I picked up an immediate tenth lol. Back when I ran a mechanical fan/ water pump

 

ittaz54: There should be plenty of chassis dinos in the greater Cleveland area where you can go to find out the rear wheel HP of your car! Have a blast!

 

That was one of the tests fans they used. The biggest hp loss was the stamped steel aftermarket fans you use to see in the performance aisle at the parts stores. Then the next biggest power loss was from the OEM mechanical fans (no clutch) the the clutch fan, and no fan at all. The clutch fan and no fan was almost identical.

I have run my car back to back with no fan, and the thermal clutch fan installed many times. There was no difference. Same ET, same mph.

 

That would make sense, as with the clutch disengaged, it's effectively 'no fan'.

 

I've have the 4 blade factory no clutch fan with no shroud on my 70S, going to the Plymouth Breeze electric fans. Curious if this 4 blade draws as much as the steel 6 blade fan they test? They claim the alternator draws almost 0 running an electric fan.

 

Seems that would be possible only when the fan is not running. There is a reason why a good fan draws 30 Amps or more, and you can't get 30 Amps out of an alternator for free.

 

Alternators are sometimes used as resistance in exercise machines. You sure can feel the drag when it loads up. I have no clue how much amperage is being drawn but my legs sure could notice it on a stationary bike. Despite that, I like my electric fan.

 

My dual fans draw very little. With that being said all I can say is that when I tossed the belt mt car always ran faster. My very first time at the track my car ran bottom 14's 14.1 14.2 etc etc. On one pass I did a hairy burnout and tossed the belt in the burnout box. I ran a 13.99 🤣🤣🤣. I'm coming down the return road overheating didn't realize it until I got my time slip lol. Then there was the time I went back to mechanical fan using a clutch unit and I removed the fan and water pump pulley and went electric drive in the pump and back to my electric fans.

 

In general yes I agree but I think there is just the right mix to get a decent idea in this case. 2 of the 3 significant power enhancing mods fall in under the gross rating. Headers and true dual exhaust are factory gross rating components. His cam specs are the only real wild card... Other than that all other moves are minimal, to sideways, to negative like the 650 edelbrock.


Absolutely 100%, unfortunately the track is not everybody's cup of tea. Myself I absolutely love it. If I were wealthy I would have a 1/8 mile track on my property...

In a way I like being my own "engine masters".

We'll over 150 passes between my 87 442 and 69 Supreme. Playing all sorts of games. True dual snorkel with hoses to the grill, to no air filter or housing whatsoever, to everything in-between. Short tires, tire pressure... TV cable adjustments. 3 belts down to 1 belt.... timing advance, synthetic oil, conventional oil, etc....

 

He will likely be disappointed as most are unless he considers how it relates to other ratings methods. Chassis dyno results are unimpressive by nature...

HotRod 1968 chassis dynoed a stock F85 310 HP stick 350 with headers and saw 215 HP to the wheels. Eventually they swapped in a 325HP W31 with headers and saw 225 HP to the wheels. Yet that W31 setup ran a 14.0 @ 99 MPH with stock tires, which is awesome for a 1968 350. That's big block muscle era W30 territory, from headers.

P.S. eventually they fine tuned the W31 setup to show 230 HP on the chassis dyno. With slicks it ran 13.20 @ 106 MPH.

In one word... STELLAR



Good for you, my 67 330 came like your 70S. 4 blade fixed no shroud. Ran warm to hot all the time. (Melt the coolant reservoir cap into the antifreeze hot.) HP consuming and poor cooling, a double negative.

Eventually I went 3 row and electric fan. But all I ever needed was the 7 blade clutch fan and shroud combo my 69 was born with.

 

I think the chassis dyno has it's place what you have to remember the different between the chassis dyno and the track is the motion of effectively putting the power down and out. I use my previous combo as an example when the engine first went into the car it started @ 12.90's and eventually ended up 12.20's with no major engine changes. Did I make more HP . Probably not I was just finding ways to use the power more efficiently. My current 350 I struggled to get the combination into the 11's. Once I found the achilles heel the first 11 sec pass was 11.89 then it took sometime to get it down the 11.68. but between 12.0 and 11.64 the mph was the same. So you can use engine dynos and chassis dynos but they only serve as a static number which will not always reflect the track numbers.

 

Chassis dynos are best thought of as a tuning tool. You can put the car on the rollers, run it, make a change, and immediately know what the result is. The problem is consistency. The same car on different dynos (with a different operator) can make a big difference with no changes to the car.

If all you want is a power number, a chassis dyno can provide that. To get the most out of the car you need a dyno, operator, and the patience to figure out what the car wants.

 

But that dyno number from. The chassis dyno won't always translate to the same at the track. Track bite eats up HP , suspension has alot of play , conditions , and stall speed.

 

Ok, I’ll revise my statement.

A dyno is a ENGINE tuning tool. You can use a dyno to optimize the engine setup.

A Dragstrip is a CHASSIS tuning tool. All the power in the world is useless if you can’t put it to the ground. Nothing else will verify traction, weight transfer, and overall vehicle setup as effectively as a timeslip.

A timeslip is also a great lie detector. We all know people who swear their “355 with double hump heads and 3/4 cam” makes 600hp, and runs 90mph 1/4 mile trap speed. 🙄