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403 olds in 79 TA


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Brook, not asking for much are we. Your not willing to spend $1500 for heads but want to stroke your 403 with a 455 crank? Do you own a machine shop?<P>Honestly that performer intake will feed your engine just fine. You want tire smoking torque then toss that 2.73 rearend and pickup a set of 4.11's. <P>The quadrajet is good for about one horsepower per cubic inch, after that you would be better off with a Holley. <P>Is 400 HP enough to smoke the tires at 30 MPH in a big car with an automatic, probably not even with the gears. <P>You want instant tire smoking torque, get a nitrous kit. But tell us when your going to be driving it, I want to be off the road.<P>Ohh yeah one more thing, your going to be getting about 6 mpg with the beast so you better figure out how your going afford to feed it and keep the nitrous bottle filled.<P>Realistically you can expect 400 hp without doing anything crazy like stroking it, all your going to get from stroking it is a headache and another 25 HP if your lucky. <P>If all this sounds like just some stupid old man trying to talk you out of building some really hot wild exotic one of a kind rip snorting barely idling Hot Rod, <P>I would say your right.

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Be sure you get all the facts about stroking with a 455 crank. I believe a 403 is considered a small block (short deck height)<BR>and a 400 a big block (tall deck height) even though it is 3 cu. in. smaller. Check it out to make sure.

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Find a pair of #5,6 or 7 small block Olds heads, put big valves in them, ream the head bolt holes to accept the 403's 1/2" head bolts, then do a little port matching and cleanup. Use Edelbrock's matched cam for the Performer intake, installed straight up. Get the carb and distributor blueprinted and performance curved. Small primary tube diameter headers for low end torque thru Flowmaster or DynoMax exhaust with an H-pipe. Shift kit for trans with around a 2500 stall converter, 3.73 gears and around a 27-28" tall tire. Subframe connectors are a must. It might not break the tires loose at 30 mph (though I have known some Pontiac 400 equipped cars to do that) but you'll know it's in there, and the Mustangs etc will soon find out. wink.gif" border="0

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I want to up the go-power of my olds 403 in my t/a. here's the prob though, the only aftermarket intake i can use is the edelbrock performer because it won't alter the position of the shaker scoop bolted to the carb, and i want to keep my q-jet. I've went to mondello's website and took a look around and i have no idea what to do. I want off-idle to 6000 power, try to keep some streetablity, and be able to smoke the tires at 30 mph with my 2.73 rear gear and turbo 350 tranny. can you stroke a 403 with a 455 crank??? any suggestions? oh yeah i can't really afford a pair of $1500 heads, but i would try a pair off an olds 350.<p>[ 02-27-2002: Message edited by: brook ]

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thanks for the suggestions, i really don't want to change the rear gear ratio because i like winding it up to 130+ mph, i can't switch to a HOLLEY because my air cleaner won't line up with my shaker scoop. I thought about sending my q-jet to a place like J.E.T. to have it built to my specs. and i was going to invest in the 'brock intake and cam, and more than likely the olds heads too. I already have purchased a pair of subframe connectors, and the tranny rebuild is more than likely, since the shifts are getting kind of soggy. I've looked for headers for my car, they make them for a camaro with a 350 or a t/a with a 400, but no 403. I've considered the 400 swap but I'd have to change to a different air cleaner base and those are a pain in the yang to locate. And i have considered the giggle juice, but once again the scoop wouldn't fit if i stuck a plate system under it, and a multi injection setup is little too pricey for my blood.<p>[ 02-28-2002: Message edited by: brook ]

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Here's another idea. Since you want to keep yer airplane gears and the trans has to be rebuilt anyway, get a 200-4R BUILT UP RIGHT and stick it in there. You'll have two advantages. A deeper low gear to augment the current gear ratio, and overdrive final ratio for all out top end blasts. You could still go up to 3.42-3.55 gearing and keep yer top end capability.<P>I don't really recommend the 700 for your application because (1) it has to have an adapter plate to mount to a BOP block, and (2) it has a deep first gear but a WIDE ratio between 1st and 2nd.

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yeah but what does one of those bad boys cost??? and driveshaft and new gears and probably a new posi carrier. Unless i can do the complete swap out of a later model gm car and retain my current suspension setup.

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  • 4 weeks later...

I agree with the other guys in saying that <BR>the 455 crank is not the answer, However i may be able to offer some input in this matter. My advice is this, remove all emmision control devices from your engine. Air pump, comp controled carb, Transmission if comp controlled, Distributer if comp controlled. Buy a pair of headers from your local auto store, Prefer. (O' REILLY). They do make them. Make sure you install an ACCEL highfire dist. or an MSD dist and 6pk. Have your intake and heads ported for better flow at a machine shop the price tag on that about <BR>300.00 if you don't want to have them ported it's O.K. Run Splitfire plugs at .80 gap and 87 octane fuel. Higher octane fuel was not designed to be used with the 403, It does not make your engine perform better. The 403's compression ratio is 8.5 to 1, it requires 87 Octane fuel. If you do this and adjust your timing to 6 degrees BTDC in drive at 500 RPM<BR>and adjust your carb to MAX effiecency.<BR>You can expect 400+ HP and if you downshift<BR>in drive to second at thirty you can smoke the tires all you want.

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  • 3 weeks later...

Here's a combo I ran years ago. <BR>79 403 <BR>Olds cast iron intake with the center divider cut down.<BR>Crane 272/284 duration cam.<BR>Blackjack headers and Duals.<BR>Stock Trans Am torque convertor<BR>Tire was a 245/60-14. 24.5 tall.<BR>3.50 gear (was a little to steep at the track) Maybe try something between 3.08-3.42, depending on rear tire size.<BR>It ran a best of 14.0 @ 100mph with severe traction problems. Tire was a 245/60-14. 24.5 tall.<BR>It would also get a 3rd gear scratch on the hwy.

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  • 1 month later...

Horsepower is expensive my friend. if you can't afford the whole job then brake it down into stages. Mabey rear end and tranny at one point. You do need better gears. don't worry about winding out. When the motor is built you will be able to get more rpm out of it so the top end will be a wash as long as you don't go too nuts with gears. I saw around 350 with a posi(you need to get your new power to both wheels) gears are the best power increase. Also rebuilding the tranny and getting a good torque converter even if it is a stock low rpm model will make a great increase in the seat of the pants "power" <BR> then when you get to the motor rebuild you know better what you need since it will already be alot faster. The regular old performer is a good bet for your intake. you want to build low end power if you want tire smoking good times. a decent cam and better heads and you'll be in there. I believe the biggest power increase to be had on oldsmobiles is to port match the heads to the intake and headers.<BR>Just my 2cents for what that is worth.

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  • 4 weeks later...

Hi, I know I'm new here but I have some info for you.<P>First,you can cut down a 425 steel crank, or if you want to make it simpler, get a stroker crank from mondello. either way it's gotta run you three large.<P>Second, leave your heads alone. the 403 heads are a lot beter than people give them credit for. of course, by leave them alone, I mean don't replace them. Mondello, who is admittedly expensive, really knows his stuff and can do some nice work for you. The more work the more money. Of course, for now that's out fo your budget anyway, so don't sweat it.<P>Third, most importantly, use a mondello camshaft. Regular mass market cams are optimized for a SBC, which is cool if you have a SBC. Or an AMC actually, but I digress.<P>Fourth, forget 6000 rpm for two reasons. Partially because you have a 403 but mostly because you plan to use a performer. (<I>are you sure a performer RPM wont do it for you?</I>)<P>Fifth, I think maybe your best bet, with your compression ration, which is about 8.5:1 is to spend the money on a hydraulic roller.<BR>Mondello's RH 14-22, which is $360 is a good solution. I know it's pricy but it lets you get away with stock compression and a stock or performer manifold, while making the most of what you have by using the roller setup.<BR>You'll get a pwerband of 1000-5000 which will do you plenty of good.<P>Now here's the thing...<BR>You're going to want to use a 2000-2500 RPM stall converter and run a 3.03-3.23 rear gear.<P>You run that cam, the performer, that converter and gears and headers with a good exhaust and you car will really come alive.

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