403 performance ?

[don0]

Any suggestions on the best build up for the Olds 403. I've considered the following products.Any reccomendations?
Performer RPM intake/cam/lifters
Comp Cams roller rocker kit

[don0]

Any suggestions on the best build up for the Olds 403. I've considered the following products.Any reccomendations?
Performer RPM intake/cam/lifters
Comp Cams roller rocker kit

[Cruiser]

I am not an Olds man however I believe that the 403 is a version of the small olds motor based on the 330.The weak link in these motors is the cast pistons.I believe that if you build one up this is the weakest link.There are Aluminim E-heads available for this engine however you will have to modify the intake manifold. Mondello in California sells a package for this engine.I would contact him for information on building a strong Olds motor.
However I have two T/As that came equipped with 403s ,I elected to replace them with 400-455 Poncho Power - a very easy swap.Good Luck ,
Mark B.a.k.a. Cruiser later

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[Cruiser]

Mondello is the man to talk to when building an OLDS
Mondellos address is
1103 Paso Robles St.
Paso Robles ,Ca
93446
(805)237-8808 HTTP://WWW.TCSN.NET/MONDELLO
Thank's Mark B.


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[takid455]

i myself have built a 403 and run pretty good. the main thing is switch the heads get either number 5,6 or 7a heads. these all came on w-30 and w-31 cars. the perform great w/ some minor machine work. you'll also have to get different spark plugs, the heads have different firing requirements than the 4a heads. Accel seems to work well w/ mine. goood luck

[tribute]

Looking at the date of your post I may be too late but if you are serious about building up your 403 go to transamcountry or realoldspower.com. Do a search on the 403 or ask the people there. A lot has been done lately for those of us with the 403 powerplant in our T/As.

[Badbird69]

TAKID455 is right. The stock compression on the 403 is a dismal 8:1. Swapping to the earlier heads will bring it up to 9:1 and will make the RPM cam work.(be sure to use the valve springs too) You will find it to be really sluggish with the stock heads. The Edelbrock heads have the larger big block ports but also the larger combustion chambers which puts you right back around 8:1 or less. This would be a very disappointing swap without some flat top pistons. The Comp Cams roller tipped rocker arms are crap. Spend the extra bucks and buy the full roller rockers from Mondello. They bolt right on and work nice. Either the RPM intake or the Holley Street Dominator intake work well with the combo. Motor will pull past 6500rpm with no problems. Unlike the junk cast rods that Pontiac gave us the 403 rods are virtually bulletproof. Now after spending your good money making some horsepower, don't forget to put a decent gear ratio in the rear end or it will still be a slug. Good luck

[Formula428]

I myself am a member on realoldspower, and have learned that Mondello is really not a reliable source. The weakest link in the 403's are the windowed main webs, unless you manage to find one of the 2500 solid main web 403's. Check out ROP for Olds stuff, there's good people there.

[Badbird69]

While the Pontiac faithful have a number of sources for Pontiac performance parts and information (JBP, KRE, H.O., Fulper, Nunzi, etc., etc.), the poor Olds guys have only three: Mondello, Dave Smith and Dick Miller. Like anyone in the business, they each have their followers and detractors. But each of them have catalogs and have researched parts and combos that will save you time. My favorite is Dave Smith, but that's just me. Many of my fanatical Olds buddies prefer Mondello or Dick Miller too. Having been an Olds fanatic for a number of years and shared fishing stories and wild goose chases with many other Olds fanatics, I have come to the conclusion that the 2500 solid main web 403's are simply an urban myth. Yes, I have talked with those who say they knew someone who knew someone else who had one or saw one or is hoarding one in a barn somewhere, but I have never actually seen one nor have I ever spoken to anyone who actually has one. If they did exist, a seller could name his price.....but I've never seen one for sale either. Ever since Joe Mondello said there might be some out there, Olds guys accross the country have been digging through junk yards for years. Maybe Linda Vaughn knows the answer.

[Formula428]

Yeah, it seems that finding a SMW 403 is like trying to find Atlantis.

[bmpmdf]

Moneydello is not the best source for your 403 buildup. Besides over priced, don't bet on getting reliable stuff. I would say the others recommended or John at Rocket Racing or Dave Smith would be better plus they won't charge near as much for parts. But that's based on my experiance. Which is why when I get done with the 700+hp 350 Olds, I'll have to figure out what to do with it. I'm thinking a 66 Nova SS I could land pretty easy....

[Jaggs79transam]

The Myth.

There were 2500 non windowed main 403's built
They came out in the larger cars with the towing packages.

Good luck finding one!
Mondello offers a girdle for 300 bucks that will support your bottom end up to 600hp.

and one for 3000 bucks for one 800hp and up.

You can build the 403 plenty without either just stay under 5000 rpms lol and DO NOT go over a 500 lift cam without buying the girdle

[olds]

There are many options for the 403 and most all the Olds families of motors. Unless, you have been asleep this last year, you would know about the Keith Black pistions, Bulldog Heads, Knowlton Head, Rocket Racing Heads. These are just a few of the new products. The windowed block is not a huge issue for a street motor. You can use a halo girle and mill the caps or run a full race girdle for extra insurance. You might contact FCR performance for you olds needs. The owner is very helpful. www.fcrperformance.com (http://www.fcrperformance.com)

As for iron heads.......#4 is the best kept secret about the heads to use on the 403. Only problem is that they are scarce as hell. A one yr head on a 67 330 olds. Same motor the forged cranks are found.

olds

[Badbird69]

I have had the priveledge of knowing Glenn Knowlton for the past several years and have owned several sets of Olds heads and Pontiac heads that he has worked his magic on. Not only does he have a real grasp of port design and the practical application of his craft on any brand of cylinder head, but he is a genuine good guy who is soft spoken, thoughtful, kind, intelligent, articulate, patient and ever helpful. He has earned the respect of his peers through excellence, not arrogance and his new head is very impressive. Some local Olds racers who have enjoyed success with his heads are Rob Johnson, Dave Engel, Skip Lisell and super stock racer Randy Mans. He is also the the secret weapon of several Pontiac racers on this board, so I won't mention any names. It will be interesting to see how all these new heads on the market work out. I'm just happy to see some options open up for us non-chevy guys.

As for the forged 330 cranks, yes they are killer, but unfortunately they have the early flywheel bolt pattern that requires special order (read "expensive") flexplates or flywheels. Also, a lot of stock and super stock racers use the cast 260 or 307 cranks because they are so much lighter.

Mondello says the solid main web 403's have casting #554990-4A or #557265-4A as opposed to the more common casting #557265-4B. I got to the point where I wouldn't bother even pulling the pan off a 4B block, but if it was a 4A block, I was all over it. But......well, you know......it's just another urban myth.

[einstein]

Maybe you Olds guys can answer me this: Is it possible those non-windowed 403s were used in the 1977-78 GMC motorhomes? In mid-year 77 (approx VIN sequence number 1285) GMC stopped using 455s and started using 403s. I'd seen some go 400,000 miles in a 12,000 pound coach before an overhaul. But I never thought to check the loose cores at the GMC resto shop I used to work in to see whether they were webbed or not.

On a related note, don't throw away your "J" heads. Those are the only heads that work well on the 455 GMC's. Cores are getting rare (not that they're valuable - GMC owners are still largely old guys who won't pay "collector" prices for anything; but they are needed). Anything else builds too much compression for the weight of the motorhome.

[Thumpin455_GTO]

so what you give me for like 4 sets of J's? you cant have my "E"s...

[Brutus_5150]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Badbird69:

Mondello says the solid main web 403's have casting #554990-4A or #557265-4A as opposed to the more common casting #557265-4B. I got to the point where I wouldn't bother even pulling the pan off a 4B block, but if it was a 4A block, I was all over it. But......well, you know......it's just another urban myth. <HR></BLOCKQUOTE>

When you say a 4B block, will it say 4B on the heads too, or 4A which I usually see?

BTW, I know Olds had some marine application 403's with a different cam but no clue if they were windowed or not, and I have no casting numbers.

I do know a buddy of mine a while back just threw a 268 Competiton cam, Performer intake, and Holley 650 into a 403 from a T/A, stuck into his 72 Cutlass and pulled consistant 8.5's in the eighth with a 3.42 posi. No bottom work, no head work, pretty cheap, too.

Holy ****. I just saw the date of the original post http://forums.performanceyears.com/groupee_common/emoticons/icon_rolleyes.gif oh well. Good luck to ever reads this.