Mechanical Valve Lash

[Camshaft]

I have a 340 with iron heads and a a mechanical valve train, and it's time to set the valve lash.  I don't have the exact cam specs as it was installed by the PO, but I do know that it is a Mopar Performance with a .490 lift.
Do the clearances change with different manufacturers... MP, Crane, Comp, etc?

I have spent a number of hours searching, but I didn't come up with much so any help is appreciated.

Thanks,

Cam

[Chryco Psycho]

Mopar cams have different lash to most cams , typically they call for .028 intake & .032 exhaust , I generally set them .026 / .030

[Camshaft]

Mopar cams have different lash to most cams , typically they call for .028 intake & .032 exhaust , I generally set them .026 / .030

Thanks.  That's on a hot engine right?

[nivvy]

Thanks.  That's on a hot engine right?

yes.......

[71chmark]

Do you set the lash while the engine is running?  I have seen this done on an old 302 mustang some 30 years ago.  What do set for initially (cold)? The same and then readjust after hot?

[nivvy]

Do you set the lash while the engine is running?  I have seen this done on an old 302 mustang some 30 years ago.  What do set for initially (cold)? The same and then readjust after hot?

see my updated how to:   

[Camshaft]

Mopar cams have different lash to most cams , typically they call for .028 intake & .032 exhaust , I generally set them .026 / .030

Another question... if your valve lash is way out, will it cause detonation?  I've been getting some serious pinging under load.  I went with a cooler plug and retarded the timing way back to 30*, and it cleaned up most of it, but it's still there.  The engine is supposed to be 10.7:1 compression ratio (built by PO)... kinda high for pump gas isn't it?

Thoughts?

[nivvy]

Another question... if your valve lash is way out, will it cause detonation?  I've been getting some serious pinging under load.  I went with a cooler plug and retarded the timing way back to 30*, and it cleaned up most of it, but it's still there.  The engine is supposed to be 10.7:1 compression ratio (built by PO)... kinda high for pump gas isn't it?

Thoughts?

10.71 with irons heads is a time bomb waiting to happen ............... 

[Chryco Psycho]

yes lash can contribute to ping , slightly as it can change the cam proflie & increase cylinder filling with RPM , but really not significantly
 10.7 : 1 with most of the ping gone on pump fuel is awesome , it should be pinging with that compression

[Camshaft]

Okay, so it's an excuse to buy some new aluminum heads.  I'm sure that there are a ton of threads out there on the subject... what is the most popular?  Edelbrock?

I've got so many things to do to this car... I don't know where to start!  $$$

Do you think an octane booster would help in the mean time?

[Chryco Psycho]

Octane booster will help , the Eddy heads will drop you to effectively 10:1 , personally I am not a fan of the eddy & would spend more to get a real head IMO