2TallCustomz

I have a 403 I pulled from a 79' Trans Am, and I'm not sure if its concidered to be a Small or Big block. I have a 455 and for the most part they look reletivly the same. Anyway this 403 is going in a 1972 Olds Cutlass now and I want a good engine recipe for it. The objective is to Turbo Charge this engine and also add the 442 hood and utilize the air damns. If you have any answers or ideas plz lemme know thanx for your time.

joe_padavano

The only external differences between the small block and big block Olds motors is the deck height. The 403 is a short deck motor, same as the 350, 330, 307, and 260. The 455 is a tall deck motor, as are the 425 and both versions of the 400. While the big and small blocks look externally identical, intake and exhaust manifolds are different due to the deck height differences. Big block heads will physically bolt to the small block, but the ports are larger so some small block manifolds will not seal properly.

The 403 has the dubious distinction of having windowed main webs. Under high cylinder pressures and high RPMs, this can cause the engine to spit out the crank. A much better choice for a turbo motor would be a diesel block.

2TallCustomz

I want to know if this is a good engine recipe.

1. 403 block bored .030 over (409)
2. 403 crank ground down .010
3. 350 heads from a 72 Cutlass
(How do I tell if they are 7a heads easily?)
4. stock 403 rods
5. deck the heads .030 over for a 10.1 c ratio
6. .040 head gasket
7. 2.072" valves from a W30
8. Bore cooling holes in the 350 heads to match the ones in the 403
9. Crane lifter, pushrods and springs
10. Edlebrock Performer Rpm intake (7111)
11. Holley 750 electric choke
12. Msd distributor and external coil pack
13. TH-350 tranny, 2500 stall conveter, B&M Shift kit
14. 3.08 posi in the back

Redog

It will 7a in the corner

SOunds like a good plan

captjim

What pistons and cam are you using? I would deck the block instead of milling the heads. That way you can re-use the heads and it also improves quench. Some stock replacement pistons sit as low as .050 in the hole. Also, I believe that #8 on your list is not necessary, but not certain about that.

88 coupe

Waste of money. The HEI, that came with the engine, is more than adequate for anything less than a racing engine.

It is not possible to advise you, in any of the other areas, without knowing about your actual goals, budget, expectations, driving habits, etc.

Norm

h-bomb

All of this is useless if you're running a stock cam. You didn't mention one, so we can only assume.

Oldsguy

If you want to see a lot of different engine builds, all with different goals of course; you can go over to Realoldspower.com and navigate to the sub-forum on engine builds. There are LOTS over there and you can make all the comparisons you wish. I am not saying our site cannot help you but I am just aware of that option and want to offer any help I can. Those posts on that forum often have comments about drive-ability vs. cost vs. power etc. Norm is right however, you need to consider your goals before anyone can truly say if that build you are considering is good or not and Harris has a valid point too, you didn't mention a cam which determines all the other valve train components in some cases. Good luck.

Olds64

I did some research into building a 403. I read that they were notrious for overheating. You will want to drill out the 350 heads to match the coolant passages for the 403 deck. I have also heard that it is a good idea to tap the head bolts out for 1/2" ARP head bolts instead of the stock 3/8". Just some ideas. Don't forget to consider a good cam and what you want to do with the engine and car when you are done. That will make all the difference in the world.

2TallCustomz

The cam I was planning on using would be at least a 292, I am using this as a daily driver with some nuts. I will be machining out the cooling holes in the 350 heads to match the 403 set, its like 4 holes so no biggie. Also I will tab the head bolts out to 1/2 instead of 3/8 especially since my C ratio is looking around 10:1. As far as parts and labor its no problem, i have a good engine builder I met while in the Marines and he said this should be no problem.

2TallCustomz

My driving habits are not bad, this Cutlass is probly not gonna see to much racing. But if some teenage punk needs some act right, I need this car to be able to blow their doors off. LOL

joe_padavano

First, all 77-later Olds motors use 1/2" head bolts. All 64-76 Olds motors use 7/16" (not 3/8") head bolts. If you use early heads to raise compression, drilling out the head bolt holes isn't a "good idea", it's mandatory. Second, I would NOT recommend drilling out the cooling passages on the head. The block has larger openings than necessary for cooling just to allow the sand cores to be removed after casting. The head gasket has much smaller coolant holes and anything larger than that just weakens the deck surface of the head and makes it even more difficult to get a good head gasket seal.

2TallCustomz

So Joe should I mill the Heads, or the Block deck height .030 ? Which is better?

captjim

I answered that already. Decking the block increases compression and improves quench, milling the heads only increases compression. Deck the block.

88 coupe

You should be talking to him, instead of posting on a message board.

I am familiar with that mentality. Simple problem = simple solution: Nitrous oxide.

First, find out what it actually needs. Your engine builder can help you with the teardown/inspection.

If you have 403 heads, use them.

At this power level, Olds rods are more than adequate.

Keep the CR below 8.5:1, as N²O works best in "smog" engines. Your engine builder can help you decide which pistons to use.

The existing valves in your 403 heads will do the job.

Use whatever springs/retainers come with your cam kit. Unless the pushrods are actually worn, there is no reason to replace them.

Your engine builder can help you choose the best cam for your application.

403 manifold can handle it. The Performer is a few lbs lighter.

If you already have a Q-jet, it will work as well, if not better. If it does not already have an electric choke, you can add one to it.

If you use a Holley, vacuum secondaries are best for the street.

Already covered.

Transgo P/N 350-1 is a good alternative.

Choice of rear gears (like cams) are an individual choice based on many factors. Biggest is the size of the rear tires that will be used.

Limited slip is a good idea.

Norm

Olds64

I stand corrected on the head bolt size. I knew there was something to it, I just wasn't sure of the numbers.

Make sure your coolant system is in good shape. Everything I have read indicates that 403s like to overheat if you let the radiator get in sorry shape.

joe_padavano

Agreed, particularly since the 403 already has beefier rods than other SBO motors.

I concur again. This is all about building cylinder pressure, and low CR with more nitrous is probably the way to build more power. In any case, be sure to use top-quality head gaskets.

Here I'll dissent. While the 2.000 intakes may be adequate, the 1.500 exhaust valves could use use an upgrade. At that point you MIGHTASWELL also have the intakes enlarged.

88 coupe

As part of a head job, they could. However, we do not know whether the heads even need to come off. From what we do know, that cash would be better spent on relieving the balance of the exhaust system.

Always beware of the "mightaswell". It can get very expensive, very quickly.

Norm

joe_padavano

Don't I know it...

Unfortunately at this phase of my life time is the more precious commodity, so I try to avoid doing things twice.

coppertopgmc

If you have a 455 personally I would use it unless its already in another car. I'm not really impressed with the 403. I would do what what Joe said, find the 350 diesel block. You can build a really tough stroker motor, but then again it depends on your budget?

wagonmaster

For info on the 403 check out ofe403
and for a performance build by the olds performance guru Joe Mondello, Olds 403 UnsungHero

Tim

88 coupe

Sounds like you have not checked out the solid main web version.

Not the most reliable of sources.



Also, not the most reliable of sources.

Norm

88 coupe

OK, I read it.

Looks like some random opinions were "cut" from a discussion board, and "pasted" onto that page.

Does the author have his 403 Olds confused with a 400 Chev?

Norm

wagonmaster

????????? information from one of the most noted olds engine builders/racers in the country are you kidding. give me some of the stuff you are smoking it must be real good.

J-(Chicago)

Ah, yes..... The phantom solid 403
Those are like U.F.O. sightings, right?

captjim

A guy over at ROP offered a LARGE cash bounty for a real SMW 403. As of now, unclaimed. Does not exist. Yes, Mr Mondello was mistaken, happens to us all.

88 coupe

Yes.

No.

Flames/insults/name calling, are counterproductive. They are also indications that the poster is a BS artist.

Norm

Oldsguy

Well Norm, don't be too insulted by wagonmaster's comments, I don't think he meant to flame or insult you, just his way of saying "I disagree". But then again, I am not him and should let him speak for himself I guess.
At any rate, I can attest to the fact that many, many, many people at Oldsmobile sites on the web, not only our site; do not have such a high opinion of Mr. Mondello as many people think at first thought. I have not decide for myself yet as I haven't had an opportunity to deal with his company or him personally. I said this just to show that there is quite a bit of disagreement about him and his company so it shouldn't be too surprising to see it here.

captjim

The main problem seems to be that the company and Joe aren't really together anymore, yet it still runs off of Joe's reputation. Joe is a great guy, IMO. Yes, wrong about the SMW 403, like I said, none of us is perfect, yet he has done a LOT for the Oldsmobile nation. However, deal with Lynn at Mondollar at your own risk....

Oldsguy

I have heard the from many people the same capt. Too bad for Joe.

J-(Chicago)

70 bucks for a 307 timing tab my ***.......

captjim

It really is. I saw some Mondello had underdrive pulleys that you can get on E-bay for like 1/3 the price. Lots of re-boxing. My engine builder went to the PRI show last weekend and spoke to Joe at length about flow benches. Mike said you could not meet a nicer guy, gave him his #, said to call if he needed help with anything. He runs a tech school in Tn now.

88 coupe

I answered his comment. Nothing more, nothing less.

If so, I would expect him to be mature enough to state his objection(s).

Most of them are only repeating what they read on the internet.

I have nothing but respect for Joe. He saw the problems the boat guys were having with 455 bottom ends, came up with an answer, then used it to build a thriving business.

I talked to him numerous times before he moved from So Cal, and a few times afterward. He is personable, knowledgeable, and honest.

Norm

Oldsguy

In response to both Norm and capt, I have heard the same myself. I would really like to meet him some day. I also heard about his business in TN.

captjim

Unfortunately, another sad story regarding Mondello;
http://72.22.90.30/phpBB2/viewtopic.php?t=42707

J-(Chicago)

Sigh.....
Yeah, **** them.
What a shame.
I hope things improve for them for everyone's sake.

Olds64

Here is an interesting build on an Olds 403. I know the car magazines are sometimes cheesey but it looks neat.

http://www.popularhotrodding.com/eng...ine/index.html

captjim

420 ft/lbs at 2500 rpm, that'll work!! But, not cheap at ten grand. And the heads are made of "unobtainium".

88 coupe

Another magazine ad:

You too, can have a 403 with these HP numbers. All you have to do, is buy these parts and bolt them together.

No more substance than the one http://www.mondellotwister.com/ArtUnsungH.htm that was posted earlier.

Norm

Olds64

Yeah, I don't genearlly read the car magazines because I get tired of the same old same old. You can only do so many small block shoot outs, and big block junkyard builds before it gets tiresome. Of course, with SBC and SBF engines bolt on performance is a dime a dozen. I guess they figure you can do it with Olds engines to. LoL