Which Cam - Pontiac GTO Forum
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post #1 of 6 (permalink) Old 10-17-2009, 10:26 PM Thread Starter
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Which Cam

Does a Ram Air III cam have a rough idle to it or is it smooth. I don't know how to read those cam charts. If not what cam would you recommend for that rough racy sound? 65' 389_Thanks.
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post #2 of 6 (permalink) Old 10-18-2009, 07:34 AM
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It will have a bit of an irregular idle to it but not that raged, chop you hear from the SBC's. The problem with the rough choppy idle is the torque doesn't begin building until after 2500 rpm and goes to around 6500. Most Pontiacs work better in a lower torque range and run a milder cam. You can still run more lift and duration but the lobe centers need to be wider to eliminate the chop to get the power at low rpm. A buddy of mine has a 406 sbc with a 700r4 in a 68 Camaro and he hated the rough idle cam he had. No low end power and always wanted to die at stop lights. We changed the cam for one with a wider lobe center but still has .500 lift, 284 duration. It idles almost smooth for that much lift but the torque range comes in around 1500 and pulls strong to 5,600, which is perfect for the street. The car is much easier to drive and more fun now. The rumpity-rump cams get attention at the shows and the drive-in but they aren't the best for real-life driving or street performance.

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post #3 of 6 (permalink) Old 10-18-2009, 11:00 AM
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Pontiac really did their homework back in the day. Grab yourself a `65 Tri-Power cam, it has just a slight lumpy idle, pleanty of vacuum for power brakes and lots of tourqe on the bottom end. Check out my videos in my sig, you can get an idea of what a 389 with that cam sounds like. Keep in mind I have a very conservitive exhaust on the car.
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post #4 of 6 (permalink) Old 10-18-2009, 11:22 AM
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I agree with Rukee. Put an "068" tripower cam in it, you'll thank us years from now if you drive it a lot. I put a Sig Erson Hi-Flow I in my '65 when I overhauled it in 1981. It's still in there. It lopes, it stings your eyes with the hydrocarbons at idle, it lets raw fuel into the crankcase if your idling for any length of time. Yes, it runs like stink, It sounds bad-a**, but it was a lot cooler when I was 2o years old. If you don't know how to read the cam charts, you can learn, or you can consult the experts. There are a lot of excellent websites on the 'net that have that kind of information. Jim Hand articles, etc. Good luck.
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post #5 of 6 (permalink) Old 10-18-2009, 01:50 PM
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I believe Pontiac used two different cams for the Ram Air III engines.
The 744 cam was used for 4 speed, steep geared cars (trans and gearing made up for the torque loss from the 744) and the 068 cam was used for automatics with milder gearing. Pontiac eventually switched to the 068 for all the Ram Air III engines.
I have run both cams in a '68 Firebird with a .030 389 (395cid) and the torque difference is felt, especially with an auto trans.
Here is a Bonni with a 389/068 cam engine:
Be aware that his idle is set too low.
The 068 is also known as the HO cam.
I think you'll be find with the 068 cam.
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post #6 of 6 (permalink) Old 10-18-2009, 10:20 PM Thread Starter
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Thanks for your input. I will attempt to make a good video for you. It won't stand up to Rukee though. Nice work. all I know about the cam is that the guy that I bought the motor from says it's a ram air III. I will never go that route again. I think it's best to know what's inside lol. I'm just glad you guys are so patient with me and willing to help. Thanks again to everyone. At the moment I need to wire the alternator, starter and coil. What a mess I have going there Later.
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