I have a 1980 truck engine that I installed a erson rv 15 cam and lifters in along with a older head that had been rebuild with stock valves and .080 removed from it. When this engine was stock it pulled 19 inches of vac. at 600 rpm with 130 to 135 compression. It now has 15 inches at 700 rpm with 150 to 155 c.r. Is this normal or I`m I missing some thing. I have varied the timing with no change in vac. I hope this is enough info. for some input. Thanks

What valve lash are you running?

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Casually looking for a Clifford hyperpak intake for cheap.

I see no problem with 15 inches. I've built a few V-8's that only pulled around 12 inches and they ran fine.
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California Medical Marijuana

When you use a cam with more overlap the vacuum goes down. Perfectly normal.

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Joshua

My lash is now set at a loose 012int/022exh. hot. I bit noisey but idles and revs. well. It has a stock one bbl. and exhaust for now but will have a M-1 2 bbl. and dutra dual exh. when I install it in my car. Just would like to get it as close to right before I put it in.

How much advance did you degree into your cam when you installed it?

-D.idiot

Don't most RV cams have better idle vacuum and low end torque? IE its a more mild cam than stock.

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50 chrysler,54 Plymouth, 64 Valiant conv 4 speed, 66 Valiant V8 wagon, 70 Challenger R/T 440+6 conv 4 speed,80 Colt, 98 Neon ACR,84 Honda V45 Magna
Taking care of 57 300C conv,48 T&C conv. Missing my 67 GTX and 36 Ply coupe

The Erson RV15 is more aggressive (higher lift and longer duration) than a stock slant six cam. It's still mild so it has the RV designation.

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Joshua

Your vacuum and lash sounds good to me.

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Casually looking for a Clifford hyperpak intake for cheap.

I ended up with looser lash with my RV15M RDP. It will sound a bit like a type writer when you get it right. Not obnoxiously loud, but you'll be able to hear them tapping away.
Mine liked being straight up as ground. I ordered Doc's Lobe seperation formula.

2¢

CJ

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Part of Tyrde-Browne Racing

Thanks everyone for your input. I feel better about swapping it in my valiant now. D.idiot This was my first shot at degreeing a cam I ended up with a 102 center line ,I did not use any cam bushing. Ceep You are right on the lash- after it ran for awhile it started to miss I opened up the intakes to 016/exh 026 Seems ok now.

I think that's where I ended up. Not sure about the 102° Intake Lobe center though. I'll have to look the cam card up.
Idle vacuum was close to 19" HG.

CJ

Edit: Yep. 106° Intake Center Line.

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Part of Tyrde-Browne Racing

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Part of Tyrde-Browne Racing