408 Valve train noise??

1973976022, member: 3615"]Oh my, no answers or suggestions. I just don’t know what to say to that. Kim[/QUOTE]


It’s like this. I’ve been working and building GM stuff for over 40 years. I’m certainly no expert on Mopar and obviously have a lot to learn or I wouldn’t be asking for info here.

I’ve never mentioned the builder as I’m not trying to start a pissing match over these engines as it always someone who doesn’t own one making the statement of how they are junk etc etc. or some other smart *** comment about wasting money

I guess I was hoping someone might say. “ My 408 from....does the same thing and it’s been fine for 10k miles and the reason is this or that so no worries “.


I didn’t know the rockers were not adjustable. When I called the tech line and asked the guy if he knew the brand of camshaft used and did they recommend further adjustment after break in and would it void a warranty if I did try to adjust them and his response was “ We don’t have an issue with you doing it”. Tells me he knew less about that particular engine than I did

Same as the first time I called the “ Tech Line “ asking if 18-19lbs hot oil pressure with straight 30 was normal for these/Mopar small block engines. I’ve never had a Chevy/ Ford/MG/Willys that I personally rebuilt have oil pressure that low on a fresh less than 200 mile rebuild. But as stated. I’m New to Mopars but not working on automobiles

I feel the noise is valve related either lifters or rocker arm due to lifter issues. The headers are new Dougs with provided gaskets. I’ve been chasing this noise since I replaced this engine.

I replaced the header to head and collector gaskets a second time even though I saw no evidence of them leaking with new ones treated with copper silicone and have the same noise. So I don’t believe it to be exhaust

it’s a 4 speed so no flex plate issues

The rocker arms are stock stamped steel with pushrod guide plates.

I assume the camshaft is Comp? The published specs are the same as Comp/ Nostalgia. But the tech person didn’t give a definitive confirmation


Thanks to everyone for the suggestions and help. The engine is under warranty so if this becomes a real problem instead of just an annoyance I guess it will be dealt with then.