OLDS 403 cam selection

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Rpryor

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Mar 19, 2022
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Hi everyone , first time posting. I'll try to keep this short. I have an 85 cutlass with a 403 , th350 and 3.23 posi rear. Engine was s
Tock rebuild and stored for an unknown amount of time. Flattened multiple cam lobes on first decent ride. It has an eldebrock 1406 carb, performer rpm intake,comp cams adjustable roller tip rockers. Using stock exhaust manifolds with crossover welded closed , 2 1/4 exhaust. Motor had a performer rpm cam good lopey idle. I know increasing compression would help but it's not in the budget this year. All I want to do is smoke the tires and local cruising. Should I buy another rpm cam or is there something better for torque. Not looking to race or high horsepower numbers. Ty
 

ssn696

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Jul 19, 2009
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If the engine ate the cam, plan on a full teardown to clean all the metal bits out of the oil system. If you're lucky, the filter got it, but you need to inpect the bearings and journals to make sure nothing got hurt. Especially if you will be spinning engine hard to release tire vapor.
 
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403Olds

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May 31, 2014
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I've got an Erson 18-20 in mine with more compression and a 2 1/2" exhaust. The performer RPM cam is pretty simliarly spec'd. With the 3.23 rear, it might be better to go smaller on the cam for more torque. I'd be interested to know how the RPM intake fits under the hood.
 
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Oct 14, 2008
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It is tough find any on shelf cam of any description for Olds currently. The RPM intake needs a drop base air cleaner, it did in my 88 CSC to fit under the stock hood. I am not a fan of those Edelbrock carbs. For one, too small but if it is working fine, use it. Clutch and I both lost the bottom end on Olds 350's due to flat cams. Get it torn down ASAP. You will probably only need bearings, which are also in short supply. The 204/214 cam is Ok, decent low end and very smooth idle with 19" of vacuum at 1000 rpm. I have used it in a 403. I used the Melling version as well, neither went flat. You could also get the 214/224, the 455 Performer cam. These two, along with the RPM cam are generic grinds, buy from the cheapest source/brand. These days, get whatever is in stock. What stall is your torque converter? I would hope 2000+, 2500+ is better with the rpm cam.
 
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Rpryor

n00b
Mar 19, 2022
4
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1
If the engine ate the cam, plan on a full teardown to clean all the metal bits out of the oil system. If you're lucky, the filter got it, but you need to inpect the bearings and journals to make sure nothing got hurt. Especially if you will be spinning engine hard to release tire vapor.
Thanks for the reply. She's stripped and at the machine shop as we speak
I've got an Erson 18-20 in mine with more compression and a 2 1/2" exhaust. The performer RPM cam is pretty simliarly spec'd. With the 3.23 rear, it might be better to go smaller on the cam for more torque. I'd be interested to know how the RPM intake fits under the hood.
Intake fit well with a generic chrome drop air cleaner. I actually have an extra rpm intake, new never installed. But box got wet could use a little clean up.
It is tough find any on shelf cam of any description for Olds currently. The RPM intake needs a drop base air cleaner, it did in my 88 CSC to fit under the stock hood. I am not a fan of those Edelbrock carbs. For one, too small but if it is working fine, use it. Clutch and I both lost the bottom end on Olds 350's due to flat cams. Get it torn down ASAP. You will probably only need bearings, which are also in short supply. The 204/214 cam is Ok, decent low end and very smooth idle with 19" of vacuum at 1000 rpm. I have used it in a 403. I used the Melling version as well, neither went flat. You could also get the 214/224, the 455 Performer cam. These two, along with the RPM cam are generic grinds, buy from the cheapest source/brand. These days, get whatever is in stock. What stall is your torque converter? I would hope 2000+, 2500+ is better with the rpm cam.
Ty for your reply. I stripped it down and it's at the machine shop now. Bearings actually looked pretty good. Cam Bearings not so much. The torque converter appears to be a stock replacement. I have 3 scored pistons on right bank and looking at the KB pistons. I'll find out more tomorrow from the machinist. Like I said this car won't be raced. Just local cruising and burning the tires. Would like a little lope to the idle but not if it affects power.
 
Oct 14, 2008
8,806
7,746
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Melville,Saskatchewan
You must have gotten lucky. Definitely upgrade the converter, while the motor is out. I say 2500 stall. Yeah, the KB Hyper 6cc dish pistons up the compression a lot, about 1.5 to 1 and you get a better ring pack. The RPM cam will work well with that compression boost.
 
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