valve lash for big mp cam?

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73goldduster

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so i have a mopar performance cam in my slant. included with the cam were several pages of install instructions/lit etc. the cam is mp 268-108. 268* duration 52* overlap .460" lift.

heres my problem. they included two valve lash specs. one says .028 intake, .032 exhaust. another one says .016 intake, .020 exhaust.
i ran the car for a while with the larger gap, but it was super ticky and grumpy and didn't make power. i reset the valves today to the closer specs, and yes the engine (when in park) runs GREAT!! lumpy, racey sounding idle, sounds ready to rock. drop it into drive, idle drops to 400 and it just wants to shut down. when it's moving it's great, but stop lights are an issue. i cranked up the idle speed screw, but that didn't really help, still wants to stall, and will just waste gas.

any one running this or similar cam? what valves specs are you at? will probably just split the difference when i readjust tomorrow.
 
you got it, go about .025" hot, it will still sound like it has a mechanical cam,but that`s what it is right?
 
Sounds like you have a stock stall converter? I ran a .530" solid Isky cam for 2 years, and I lashed at .018"..022" as I recall. Yes, it too was a pain with a stock stall. The 4.88 rear gear was all that saved me.
 
Double check the cam specs of the cam, Running to small a lash will burn the valves, pushrod tips and possibly the rocker will be damaged due to lack of oil.
 
yeah, stock stall converter. i should have swapped that out while engine was out. just wasn't sure exactly what i should be looking for as far as stall speed.
commando, by mechanical you mean solid lifters? if so, yes.

i sure don't wan to damage the valvetrain, so wider they go.
it's just weird how they have two wildly varying specs for lash...

i'll get out there and report back later. thanks for the tips!
 
well, reset lash at .020 intake .024 exhaust, set idle at 700 rpm.
runs like a Champ!! smooth idle, pulls hard, feels great, and no noticeable valve clacking! didn't get it too fast though. when pulling to a stop, the revs drop kinda low, stumbles slightly. got the day off tomorrow, so i'll play with carb and timing.
the fun never ends! :-D
 
.020/.024 sounds about right. What else was done when you had the engine out? Is the combo stock except for the cam? What carb?
Frank
 
offy intake
holley 390, vac secs, elec choke
head milled .090"
ss valves from enginebuilder (1.70, 1.44)
head ported/polished by me
mopar valve springs (for a 340?)
high pressure relief springs for oil pump
hooker super comp headers, dual exhaust
mopar perf. cam

slantsexy2.jpg
 
Ok looks good. How did the playing go? That cam will lump some. You may want to bite the bullit and get a little more converter. 2500-2700 would help loads.
Frank
 
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