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280/270 RDP
https://www.slantsix.org/forum/viewtopic.php?t=68296
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Author:  Montana A Body [ Wed Jul 23, 2025 2:09 pm ]
Post subject:  280/270 RDP

I have one of the Erson 280/270 RDP cam in my 225. I was wondering if anyone could tell me what the valve lash is supposed to be set at, these are .013 intake and .015 exhaust?

Author:  ceej [ Wed Jul 23, 2025 6:14 pm ]
Post subject:  Re: 280/270 RDP

As I remember my Erson RDP cam like to be quite a bit looser. Since I can't remember the lash settings, I'll leave it at that. It was looser than Erson's spec.

I used Doc's method to find lash, it worked very well. Loosen until it gets loud on you, record the lash, tighten until it starts to miss, record the lash. Adjust it to the middle based on what you want. Do it hot.

CJ

Author:  Dart270 [ Thu Jul 24, 2025 5:32 am ]
Post subject:  Re: 280/270 RDP

Hello Montana,

I have this cam running well in a 9.6:1 aluminum 225 engine in my 66 Valiant with a drool tube head. Runs great. I installed it at 104 deg intake centerline and optimized the lash. I am on a trip now and did not write down the lash numbers in my cam notes - oops. I write them on the car or valve cover once I find them and will look at that when I get home. If I forget, ping me next Th-Sat so I can make sure to look. IIRC, it was around 0.018" intake and 0.024" exhaust. It will idle better and make better low end power than with whatever lash specs Erson said, and you will not sacrifice any meaningful upper end power.

FYI, except for Mopar Perf cams, I have not found a cam company that delivered good lash specs on their sheet.

Lou

Author:  Montana A Body [ Thu Jul 24, 2025 12:26 pm ]
Post subject:  Re: 280/270 RDP

Thanks to CJ and Lou both for your help.

Author:  Montana A Body [ Thu Jul 24, 2025 1:14 pm ]
Post subject:  Re: 280/270 RDP

The cam was installed +4. Any suggestion on what timing should be set at to start with?

Author:  Dart270 [ Fri Jul 25, 2025 5:40 am ]
Post subject:  Re: 280/270 RDP

Do you mean ignition timing? If you have it installed at 104 CL, then you have already set the cam timing. I am assuming you measured that will degree wheel, dial indicator, etc?

As for lash, if you are wanting to set it to run, I would start with 0.018" int and 0.024" and that will be pretty close.

Best, Lou

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