VWBeamer

Hi

I have just gotten a 1977 Cutlass with a stock 350. the car is in really good shape and i want to keep it looking stock.

The problem is it has very little power. As far as i can tell it is bone stock with 76,000 miles.

1. I purchased a dual exhaust system from Summit, but have not installed it.
Should i make it true duals or just Y it off the stock exhaust system where it dumps into the converter. I'm planning on removing the converter

2.I'm guessing the motor could use some more compression, what's the limit with the stock cam? Is there a better flowing head available for a reasonable price? I'm thinking of removing the heads and milling them for more compression and cleaning up the ports. How much can be taken off the heads?

I didn't want to get into the shortblock, or the cam unless big gains were to be had.

I'm not looking for a tire burner, just something that will keep up with traffic.

Thanks in advance.

Warhead

Do a tune up on it with fresh parts (plugs, wires cap etc.) and make sure that the q-jet is going to full throttle on the secondary side. Many I have seen will not. Maybe even a rebuild on the q-jet could be in order. Check timing for 36 degrees at 3000 rpm. Make sure vacuum advance is working from timed spark port.
THEN the dual exhaust, AND a set of 3.23, or 3.42 gears in back will make a world of difference. You can probably find the gears in the wrecking yard from a Chevy truck CHEAP.
Jim

Warhead

P.S. Make sure the catalitic converter is not plugged up, also.

88 coupe

True duals = Dual exhaust, as opposed to fake duals. The second exhaust usually adds a noticeable power gain.

Y pipe = Dual outlet exhaust (fake duals). For appearance only. Gain, if any, will not be enough to measure.

Norm

VWBeamer

Thanks, I believe i can remove the cat without hassle from authorities, so it's no concern.

any information on these heads? Think I could up the CR to 8.5 or 9?

How would the steeper rear gears affect Gas mileage? i suspected the poor gearing is largly responsible for the poor acceleration.

Norm, think I should get a shaved cam? a friend of mine has one in 76 442 and it runs 8's. (wink)

Warhead

Steeper gears will cause the engine to spin more for each mile driven. Gives more mechanical leverage to move car. More fuel is burned for given distance, giving more effort towards moving vehicle, and also burning more fuel. If you have a mid 2 series gear, a low 3.?, it will make a hell of a difference in accelleration. Cost will be more fuel spent. There is a happy medium somewhere in this for you.

Do the tune-up first.

JMO
Jim

VWBeamer

Thanks, I've been reading the whole site and related links.

I think i'm going to try and find some better heads, true dual exhaust and see what happens.

i might move to a low 3.Xx gear.

I know from drag racing, gears make a huge difference, especially off the line.

J-(Chicago)

That looks like a bad buggy there.
The hoods on those always remind me of The Rolling Stones.
Strange how the human mind associates things.

VWBeamer

Your right, i never noticed

Here's my Cutlass-

78cutlass

That's a clean looking '77. You could raise your compression a bit by adding a set of Olds 350 #5 heads (64cc). Also, you could replace your TH350 transmission with a 4-speed OD transmission (700R4 or 2004R) and change gears to 3.73 or 3.42. If you go the head route, replace your timing chain and oil pump while your at it. A car that nice deserves a freshly rebuilt motor.

If you could "swing it", do a complete engine rebuild via a reputable shop. A quality Olds 350 rebuild might cost between $3,500.-$4,000. If you decide to go that route in the future, try to find an unrebuilt '69-'72 Olds 350 motor, or even an Olds 403. These offer good foundations for a strong runner, especially if the parts are matched properly. Realistically, you could have a mild small-block Olds under your hood that makes 350 horses / 370 FT LBS of torque.

PS - the 4-speed OD will do wonders for off-the-line acceleration & driveability for cruising; also, you could add a Holley Pro-Jection 4D set-up (throttle body fuel injection) for an AWESOME TIRE FRYING COMBO!

Take Care,
Rolo

Oldsguy

You car is gorgeous! Love the red on red.

Chaney3000

Nice car VW.

VWBeamer

Thanks for the compliments.

I was a hardcore VW guy, but this Olds has won me over.

Olds64

That is a pretty car. Too bad they are so small. After doing a tune up and rebuilding the carburetor I suggest headers and an aftermarket cam. Those would be the easiest ways to bump up your horse power without doing too much to the car.

VWBeamer

Yea, the vw only weighs in at 1500 lbs, with 200 hp. No ac, no radio, rides like a buck board, and noisy as hell.

I think that's why i love the Oldsmobile, it's like, wow, i got a real car now.

I love them both, but they are totally different.

Warhead

#5 heads start at 68cc's, NOT 64cc. A valvejob, would make it even larger (like 70-71cc's), unless the heads are milled. It may not sound like alot, but it makes a difference for an honest measurement.

His 3A heads should be around 75cc's.

daverbmxer

What year and model is a good donor for the #5 heads? Anything else to look out for? How hard is it to port and polish the #5 heads? How much can you shave the head while still making it drivable and what gains would result?

joe_padavano

And as I'm sure you know, the as-cast volumes are usually a few CCs larger than the blueprint specs to allow for a head resurfacing in addition to production tolerances.

The #5s were used on every 350 Olds built in 1968-1969, including W-31s. They are no different to work on than any other Olds head. The amount you can cut is a function of how much CR you plan to run and what the rest of the engine looks like. For example, the current FelPro blue head gaskets have significantly greater compressed thickness than the OEM steel shim gaskets. This will drop compression. You need to get an accurate measurement of your deck height, piston dish volume, head gasket compressed height, and desired chamber volume to determine actual CR.

88 coupe

So they would have less, than advertised, compression?

How did "tolerance stack" figure into the decision?

These heads normally do not warp, and seldom need resurfacing.

Not to forget the bore, stroke, rod length, and pin (compression) height of the piston.

Norm

joe_padavano

As you know, all mass production items have a +/- dimensional tolerance. In the aerospace industry we try to design parts in a way that the machining and fabrication tolerances can be accommodated without excessive part rejection or rework. Since the sand cores can vary, I've always ASSUMED (and yes, I know what happens when one assumes...) that the larger-than-advertised chamber volumes seen on as-cast heads was an allowance for variables like core shrinkage and shift such that the CR would never exceed the design point. This is the more conservative design approach, since the CR would never exceed the factory spec and thus detonation should not have been a problem when the car was tuned to factory specs. Yes it means that the CR was often slightly below the factory spec, but that's why you blueprint motors, right?

Maybe so, but again, as an engineer, I would design for that option since one rarely has perfect knowledge of the future. This is unlike today's motors, where there is virtually no margin on (for example) wall thickness to allow an overbore.

Correct. I'll admit that sometimes (like when I'm writing posts when I really should be paying attention to a meeting ) I may not be 100% complete in my responses.

Oldsguy

He was talking about your cutlass. He is a four door hardtop man, loves those B bodies.....

VWBeamer

LOL. It's huge compared to the VW

88 coupe

In production, the target is zero and the first article should meet all nominal (± 0) dimensions. Tolerances define the acceptable deviation before production must be halted for adjustment/retooling/etc.

An example of stacked tolerances, as applied to this thread, would be:

As we can see, a 9.0:1 Mechanical CR could easily turn into an 8.7, or a 9.3.

Assumptions are not always a bad thing. If all the available data has been used we may not have any other choice. And many times they turn out to be accurate.

Were the volumes ever published? The only data I'm aware of, has come from builders/rebuilders, after the fact. The above post by Warhead, for example.

I would expect the design point to have the same tolerance the foundry/machine shop used.

Not a problem if the specs were a bit conservative.

The term was originally used in reference to NHRA stock classes. Blueprinting was the manipulation of factory tolerances, to achieve maximum power, while staying “inside” the original specs.

Which leads us to my point, and coincidentally, one of the basic reasons behind my posting style.

You've told us what you would do, and I don't disagree with your thinking.

My question is: What was actually done?


Sounds like you think you committed a crime.

Not a crime.

The “crime” is when omissions/errors of fact, are allowed to go uncorrected. 442.com/Oldsfaq is a good example of the consequences.

Norm

VWBeamer

I added the dual exhaust, true duals Like Norm likes.

good improvement. I think more CR and more torque multiplication via 3.23 rear end gears are next.

88 coupe

Norm only has a problem with the redundancy in the name. Dual outlet exhaust looked great on my Specials and Skylarks.

If, at a 30-40 miles per hour cruise, you feel/hear a slight surge/miss you can go a "taste" richer on the primaries. If not, relax and enjoy it.

A 2200 RPM, or so, stall converter will work well with that combination. Do the gears first.

Norm

joe_padavano

Unfortunately, I am not aware of any published factory data that describes as-cast chamber volumes. The only published data is the minimum CC data that NHRA publishes, which presumably came from the factory originally, but obviously these are not as-cast. I will note that some of the chamber size data that's listed in the FAQ was based on measurements performed by Chris Witt. Note that most of these measurements were based on a single data point (ie, a single copy of each casting) and thus should not be taken as gospel but an indication only.