Which camshaft would be the closest replacement for a stock '73 400 HP 4BBL? What about timing set and oil pump for the same engine?

As I've been looking up these parts, there seems to be a lot of reference crossover between the base and HP 400 motor for this year. Thanks!

MELLING SPD31 is supposed to be the stock HP cam for that.

The stock camshaft is the same Magnum one, the first one of the Purple camshaft series

I'd get a 3 keyway roller timing chain set & put in "advanced" & a parts house std vol oil pump will work fine for you

The Summit 6400 is the same cam. I have one in my 440 and I love it.

Thanks for all of the input. So, in an attempt to freshen up a stock engine, I originally ordered an Elgin E-327-S cam kit, Melling M-63 oil pump, and a Cloye's C-3010K timing kit. Being a '73, I didn't realize that there was a difference with it being a HP 4bbl engine. I believe the above cam is for the 2bbl version of the 400. In addition to the suggestions mentioned here, the Elgin E-1094-P also looks to be an relatively stock HP alternative according to factory specs. I am running one of those in a 440 that I have. If I return the cam and replace with one for the 4bbl, would the above pump and timing kit still work with the HP engine?

This is a good running motor and I am not looking to rebuild, but I noticed that the timing chain felt loose on inspection so I figured I'd change it and thought it wouldn't be a bad idea to change the cam, lifters and oil pump while I was in there. So this brings me to another question for the engine guys: Since it is running good, is it even worth changing the cam and oil pump out, or just change the timing chain and gears and call it good? Odometer shows a little over 100K miles. Thanks in advance!

unless it's broke (or used up, like your timing chain set) don't "fix-it"

a saying we used at work : "if it ain't broke, keep fixin' it 'till it is !"

I like the logic of the above posts!

I do think it would be a good idea to replace timing kit though, as loose as the chain is. I have not removed the cover yet, but when checking the tension of the chain via the fuel pump orifice, I can actually pull the chain into the side of the cover. That seems way too loose. I am borrowing a harmonic balancer puller, but haven't picked it up yet so I can remove the cover.

Also, the timing kit I picked up is a 38 tooth cam sprocket, with a 19 tooth crank sprocket. There is a racing/high performance version available with 50 cam and 25 crank tooth sprockets. Which one am I likely to find in my factory HP engine?

Thanks!

all engines in the same family will have the same tooth count on the sprockets which is 25/50 on a big block iirc. Cloyes brand has gotten some bad reviews lately

as mentioned the Purple shaft camshaft ( the basic one, first on the line ) is the correct one for 72/73 400 Magnums!!!... 74s are another story