74omega

Here is my scenario,

I have a 74' Oldsmobile omega hatchback with a 350 rocket. It is pretty much factory stock.

I bought a brand new Edelbrock performer manifold for it and put a 650 double pumper 6210 on her and it has true dual exhaust hung on (headerless though) and de-smogged it.

I also have a set of #5 heads I obtained for free on a used edelbrock manifold deal.

Recently I ran across a deal on a 78' 403 longblock, great compression, with aluminum manifold for $50. I could not pass it up (actually I have not seen it yet, My brother is picking it up now).

What I want from my car is a GOOD 300+HP daily driver with my factory working a/c etc..

My questions are many.

1. Should I stick with my 74' cast 350 block for a mild performance re-build, slap the re-done #5 heads and have some downtime??

2. Should I stick the 78' 403 on a stand and mild performance re-build that one while I enjoy my car? or is the 403 a waste of money/time..

3 a,b,c. Is this a direct swap, meaning all my components are the same and my a/c etc.. will be plug and play? I.E. I own 3 350 aluminum edelbrock manifolds and the one for the 403 that is coming so are these interchangeable right? The #5 heads will slap right on this?

4. If I buy the costly Hooker headers for the 350 Omega only based fitment, will it fit the same with the 403 in there?

Any input will be appreciated, thanks. Sorry for being long-winded.

Wireman134

Hello there. The 350 is a stronger block, but for 300 or so hp not turning more than 5000 rpm regularly the 403 will offer more low end torque. I would take my time and build the 403 with the #5 heads. Heads are not a direct bolt on, you need to reaming 1/2" bolt holes for head bolts, and add cooling holes to match the block. Mod the oiling system with a deep pan, high pressure pump or spring, cross drilled & chamfered crank, will help the bottom end. Same block dimensions and mounting locations. Small block headers for your chassis will bolt right up. Look here for info on all Olds engines;http://oldsjunction.classicoldsmobil...IDEngineDetail

Olds64

I agree. The 403 is a strong motor as long as you won't be turning 5000+ rpm. Like they say, there is no replacement for displacement.

joe_padavano

Actually, the way I heard it is "The only replacement for cubic inches is rectangular dollars."

74omega

OK.. 403 it is.

The 403 engine is exceptionally clean, It also has a 307 aluminum manifold on it for some reason..

BUT will the 403 4a heads be OK to use as long I put a decent cam/mani/carb and gearing is in the 3.40's? Will it have enough guts to NOT feel like my current 350 smogger?

Reason, I think I will save the #5 heads when I pull the 350 out and build that one as well In my spare time.

If I do "mod" (1/2 bolts & drilled water jackets) the #5 heads to the 403 would that now make them only 403 usable?

Thanks.

joe_padavano

The A4 intake is a perfectly acceptable, inexpensive swap for a cast iron 403 intake. If it's an A5, it's not even a good doorstop.

Wireman134

That sounds good. The #5 heads would be for use with thee 403 if modified. The 403 block would need to have a .0" piston to deck height to get to stock compression ratio with a .040" head gasket and stock dished pistons. Cut the 4A heads like .020" will net you a additional .25 point boost in CR.

J-(Chicago)

I'd build up the 350 with the 5 heads, but that's just me.
I traded my 403 block and crank for a nice set of battery cables for my 350

74omega

Cool. I'll just do a basic re-build master kit, have the heads re-built and milled .020. I plan on doing a ~2200 stall converter? Then I will get back to you guys on a decent Cam decision for this setup once I lock in my Rear-end gear choice and tell you what I actually did on the re-build..

When the 403 Is finished and installed, then I will start on the 350 but do a Wicked build-up on it.

On a side-note I will take the car out to the track on it's first 1/4 mile run with its current state to see what it does as a baseline to compare. LOL.. Just for kicks.

88 coupe

I'm guessing, this one came from the page that is linked below.

Norm

J-(Chicago)

Sounds like a good plan.
Good luck and don't frag it.
As far as a baseline comparison......What will you be comparing your new timeslip to?
Bone Stock head times VS. milled heads times?
or stock convertor times vs 2200 stall times?

74omega

My current low-miles 74' 350 with edelbrock manifold, de-smogged, 650cfm DP, and duals, 3.08 peg leg..

To rebuilt 403 ,milled .20 heads, 307 A4 manifold , 650 DP, and duals, camshaft, 2200 stall, 3.40 posi...

Probably a unfair battle but hey.. I would LOVE to see the difference on paper. I am a avid bracket racer in my other less cylinder cars..

When I de-smogged the 350 and put the true duals it was still gutless lol. It would not break them from a stop and BARELY could do a brake-stand.

With the addition of the edelbrock manifold and 650 Holley DP it can break them loose with ease from a stop, without brakes. It also has a whole lot of mid-top power as compared to before.

Excuse my ignorance as I have never owned a "muscle car" per-say. I am a classic Import/DSM turbo guy.

I will get Pics up ASAP of my car/build/engines etc. I will be asking a-lot of technical questions soon..

J-(Chicago)

Yeah, apples to oranges at that point, but still sounds like a fun project. It would be great to see a piece by piece time slip comparison of all those mods, but it would take a good 5 man pit team to get all that stuff swapped out in 1 day at the track.

My biggest head scratcher here so far is why you are swapping an edelbrock manifold for a 307 manifold.
THAT is a direct comparison I'd love to see same day at the track.

74omega

I wanted to keep the brand new Edelbrock Mani I just bolted on for the 350 build.

The 403 has a 307 A4 aluminum one on as it sits. I do have 2 more used Edelbrock performer mani's (3711's?) I could ,with ease , bolt on and dyno compare to the A4. My friend (best man at my wedding) owns a local muffler/import performance shop with dyno. He is the one who hung my dual exhaust. I guess I'll use whatever produces the best results..

Thanks for the great Idea. I totally forgot about my "dyno connection" lol.

74omega

I was told by a source (my brother) That If I were to mill the heads .020 I would have to compensate and mill the intake manifold I am using to match up adding to machining costs. Is this correct? Or Is he BS'ing me.

If so I will just keep the heads stock height and better use the cash to get the Keith black pistons that FCR has for the 403 to solve the compression issues..

88 coupe

Not with an Olds.

Unlike Brand X, Olds heads and manifold mating surfaces are at the same 45° angle. 20 off the heads would create a 20 mismatch (assuming they were matched) in the ports and bolt holes.

Bolts should fit fine, and the port mismatch would not be a problem. Port match, to compensate, is always a good idea but seldom results in a significant power gain.

Norm

Warhead

Put the #5 heads on the 403, using at least a 2.00 inch intake valve when you rebuild the heads. Drill the head bolts, AND 1 of the locator pin hole to the correct size. You will understand this if ever you look at the chamber side of an Olds head up close.
Ditch the 650 DP. You are giving up power with this carb.
This will need a 750 Holley, or Q-jet to feed it.
Try a stub stack on the 650, it will prove my point.
Fill the exhaust crossover. 20 Hp.
Use an electric choke if you must.
The 403 combo will make 65-70 HP more (at least), than the 350 with the same parts (cam, compression, manifold, and heads). REALLY!
The 403 gives you an additional .300 bore size.
The same 350 cylinder head will flow more on a 403 block.
This is why all of the bomber guys are running this engine now.
Jim

cutlassefi

I agree with Jim, but don't cross drill the crank, you don't need a 7 qt. pan and with oil restrictors and only a 300hp engine you probably don't even need a high volume/pressure pump. Getting 300hp out of 5a headed 403 isn't that difficult. Balance it, use decent parts and you'll be fine.

Note; Can't believe it runs that well with a Double Pump Holley without alot of gear and converter. Normally they don't. And yes you do sometimes need to surface the manifold after cutting the heads or deck. The bolts holes/ports get out of vertical alignment.

88 coupe

Or the heads? And for a .020" cut?

Yes, as was already covered in a previous post.

Port match (and hole "adjustment") would address the actual problem.

Milling would not necessarily align the ports accurately, but it would limit its use to that particular set of heads, or manifold.

Norm

88 coupe

Yours was the first mention of "cross drilling".

A small "tear drop" shaped cut, at each delivery hole, will do the same (if not a better) job of increasing oil flow.

Norm

Wireman134

Keep it in mind, the weak link in a Olds engine is the oiling. Oil tends to stay on the top of the engine to long, getting it to drain to the pan is vital. The stock pan only holds 4 qts. barely adequate for higher highway rpm use, let alone a trip down the strip. Cross drilling will ensure oil volume at the journals, a little extra pressure will maintain oil supply through out engine. A high volume pump would just suck the pan supply faster. Main restrictors are cheap and restrict oil to the cam bearings only (how much does the cam really need) , not to the rockers, to keep the oil from the top end use a lifter bore restrictors or a push rod restrictor. Olds engines oil the top end before the crank journals. A good supply (volume) of oil to all the vitals IMO is the key to longevity in any engine.

A small "tear drop" shaped cut is a chamfer

88 coupe

As noted in several previous threads, https://classicoldsmobile.com/forums...ary-where.html there is nothing wrong with the Olds oiling system.

Only if the return passages become restricted. This would be a maintenance, not a design, issue.

5+ if the filter/system is included. More than adequate for most applications.

Internet myth.

In the day, if an Olds was was not capable of "cruising" for hours, at those speeds, they would have lost a lot of market share to their competitors.

If so, wouldn't it have been done by the factory?

Whether a crank is "Cross drilled" or not, has no effect on oil pressure.

Explain how, all else being equal, a "high volume" pump could do so, if a "standard" pump could not.

Not where the "restriction" (if, indeed they would be a restriction) would be needed.

My guess is: About what gets past the bearing clearances. Since, from there, it goes directly back to the pan, it doesn't matter much.

Normally done, if solid lifters are used, as they only need enough oil for lubrication.

Not done, if hydraulics are used, as they rely on adequate oil pressure to work properly.

If one felt the need to restrict oil to the rockers/springs, that would be the only logical choice.

Does this mean that the oil to the crank, is fed from the "valley" after it leaves the heads? Is why the pan can get "pumped dry"?

Norm

J-(Chicago)

Agreed.
However, the drainback passages in Olds heads are prone to clogging from my experience. Slightly modifying them is a good idea. Same concept as a gutter downspout on a house. All it takes is 1 or 2 sticks/pieces of gasket or other debree, and then the sludge, bearing material, stopleak/ whatever the case may be easily blocks them.

Most beginner to average drivers don't pull the valve covers every oil change and inspect/maintain their heads. Once the oil has reached the top of the valve covers it's job is done as far as I'm concerned, and getting it back down the drainbacks a little quicker is a good thing.

J-(Chicago)

I recently pulled apart a 72 455 block with 70k original miles on it, and was disghusted by what I found in the heads. The driver's side drainback was clogged solid. I took some pictures of the carnage and could post them if anyone likes.

Wireman134

Once again Norm has all the answers to all of the questions. Oil travels up to the lifters, from the lifter valley passages to the timing chain down to the crank. Norm.
Cross drilling the crank may not be necessary, and chamfering the oil holes helps. I starter doing it 25 years ago, not a internet myth, unless you did create the internet? Hot Rod's "Junk Yard Dog" article explains. The stock oil pan does in fact hold 4 qts. by design, and the pump draws oil from the pan, not the filter. A HV pump will pump a pan dry faster, and would not be used with a stock pan or inadequate oil supply. Besides most modern V8's have larger capacity oil pans, and why is that Norm? The more oil in the system the more cooling effect it has, oil viscosity is mainained. Let all answer a question with a question? Engine designs do evolve, and improvments are made weather you aprove or not. Chears

J-(Chicago)

Ok. Sounds like we have a good discussion and a little experience here.
Wireman, I am curious if you chamfer the oil drainbacks on the heads. AND, if so, did you also enlarge the machined holes inside the head? I chamfered the top (bigger opening at the top) of the drainback holes on my heads just for kicks, but am curious how much material can be removed inside the smaller hole inside the head. As of right now, I'm not sure if it is the equivalent of polishing a turd.

I plan on buying 2 identical plastic funnels with a steep ridge inside (similar to what the olds heads have) and filing this ridge down on one of them. I will then pour the same amount of water in them and see which one drains faster into their perspective buckets to confirm/debunk this idea.

Also, I don't believe that you can suck the pan dry on the Olds if it's filled to proper capacity, and the pickup is in the correct location. The valve covers would have to be filled to the top and have oiloozing out of the crankcase. I've never seen anything like that. I do believe you can have a little too much up top however, especially with those small drainback openings.

J-(Chicago)

74 Omega....
I do realize we're on a tangent here, but perhaps when you build up your monster 350, some of these things may/may not help you decide what to do.

citcapp

When I built my 455 it was for full out launches and high rpm use. Right around 480 to 500 hp. I studied all of the theories about oiling published by the main Olds builders on the web sites. None of them had the same or similar ideas on Olds oiling. Some say you have to use restrictors, high volumn oil pumps. others say no restrictors and high pressure oil pumps. All of then only seemed to agree on only one thing. That is make sure the oil passages from the heads to the block line up correctly. When I built my engine the machine shop foreman and myself checked this out. In my case they did not line up well. About half the of the hole in both heads mated with the block the remainder of the hole was blocked by the metal of the block. The foreman drilled out the head holes to match the block. I have ran the engine to 5000 rpm with hard launches and there has never been a drop in oil pressure. 40 lbs idle, 60 lbs when running hard. The only other things I did was a 7 quart oil pan with a windage tray and a high volumn oil pump.

For a normal driver I would recomend checking out the line up of the oil drain holes to the block drain holes and if they are ok then I would not worry about it at all.

cutlassefi

88 Coupe - Pay attention, Wireman mentioned "cross drill and chamfer crank" before me.

And yes, you would have to either mill the manifold or the manifold surface of the heads. I'm trying to keep things simple. Hope you can keep up here.

74omega

I am keeping up well, drinking my Beer and learning.. You guys are great and helping big time with my "Olds education."

The 403 arrived today and it is in great exterior visual shape, but thats not what counts. I will strip it down later tonight and see what I got internally. The guy said it was good compression across the board but that means nothing to me. For $50 its a deal I would say. It is complete with new starter, new fuel pump, new EGR (that will go in the trash) manifolds etc..

I am definitely going to keep the #5 heads for the 350 build and use the 4A heads for the 403 with the Keith Black pistons here http://store.summitracing.com/partde...8&autoview=sku. I want to keep this build under $2000,well thats my goal at least, for the 403 including machine work.(my brother is a machinist, but charges me 1/2. Go figure. He is a BIG ford guy and knows NOTHING about olds) I will concentrate on the oil drains and system in general along with cooling.

Anyone have a good simplified formula or recommendation for a $2000 403 using the 4A heads? I plan on getting a Re-ring kit and just get the other stuff cam/timing/pumps etc. independently.

Wireman134

Nope, on chamfering of the return holes here. Though it is a fine idea, and may be required in some applications. With my street engine, a deep pan with a blueprinted stock pump supplying a little more pressure , and possibly a cross drilled crank. Change the oil regularly to keep the sludge from building up and clogging those passages. The extra oil is there in the pan when I need it to keep those bearings cool. The average oil pump pumps like 1gpm at 3000rpm, 2gpm @6000rpm at any given time during a long sustained speed run around half of the oil in a 4qt pan will be available to pump. I've never experienced a pump sucking air, but I bet it happens. If the engine is out, a higher capacity pan goes on, just consider it cheep insurance. My 2 cents. What ever is in your means, if your not winding it up past 5K rpm or running a road race on the highway keep it stock.

cutlassefi

If your brother is a good machinist, he doesn't really have to know anything about a Ford, Olds or whatever. All he needs to know is how to do whatever it is you want him to do, no matter what make it is. Assembly may be a different animal but machining shouldn't be.

HARDLUCK88

id be interested in seeing that.

88 coupe

Yes he did. Thanks for pointing it out.

I will ask again:

If so, how much would be taken off, to make the ports match?

And I am trying to keep things educational. Do you think it is possible that we are both aiming for the same goal?

Norm

88 coupe

No reason to.

Regularly scheduled (according to conditions) oil/filter changes are enough to keep it from happening. Factory recommendations, to replace the filter at every other oil change, would have been a prime contributor.

It cannot do any harm.

Norm

88 coupe

Another Internet myth.

If so, how does oil pressure get to the crank?

Congratulations, I think.

The pan is only one part of the oiling system.

Nothing to do with anything.

Pump sends it through the filter, which is part of the system. When the pump stops, over a quart is left in the system. Most is left in the filter and system, some returns to the pan.

During your "25 years", have you ever heard the phrase, "one quart for the filter"?

No different than the statement that raised the question.

No one learns anything when a poster simply repeats what he/she heard/said. The knowledge comes from understanding how/why.

Here it is, again:

If you cannot tell us, just say so.

Norm

88 coupe

It can't do any harm.

I would be interested in knowing whether the difference can be measured.

Many times, because of this myth, the pickup is placed too close to the bottom of the pan. First thing my machinist cautioned me about.

If they were a problem, it would have been addressed. Likely while they were involved with racing. Starting with the D heads, for instance?

Norm

88 coupe

The Mondello school of engine building says to use them. No one says they will harm anything.

Recommended by everyone, whether they are needed or not.

And whether they know why, or not. Either way, it cannot hurt.

Not needed if the proper bearing clearances, for the application, are used but they will not cause a problem.

Both standard and high volume pumps can handle it. Usually recommended to shim the regulator spring, to fit the application.

Is a "high pressure" pump, even made for these engines?

I understand, this is normal for A, B, and C heads. Don't know about anything newer.

But, it can't hurt to match up the holes.

60s in the 1.58s, and 7100 RPM.

Pressure was 65# at 3500, gradually went down to 55# at 5500, then stayed there to 7100.

8 qt on the 455s, and 7 qt on the 425. No windage tray, 4 quarts in the pan, and the push rods were restricted with pipe cleaners.

Norm

Wireman134

Norm, don't stop now your on a roll...

J-(Chicago)

Good point. Something I didn't think about. Thanks.