Freshening the engine and had the lifters out of the bores, normally I try to keep the lifters on the same lobes but they got moved around on the bench. How important is it to keep them matched? The cam is a Comp .590 mechanical with 924 springs. Thx for your help. BP.

Well, its definitely not recommended to mix them up but I have had that happen to me before and all I did was put break in lube on them and remove the inner springs and break them in like it was a new cam.

Done that 3 or 4 times in the past without any problems.

Well in the past before I new better from 1983 to about1997 I never matched them (would just put in a tin) with no problems. On my Ultradyne 263/271 .597/.620 in the winter of 2002 I dumped them out on the floor by?? well I was going to say accident but brain fart!!! LOL!!! so no idea where they came out of. back together with moly lube! Ran for 5 more years and hundreds of runs after that. sold to a buddy and he ran it a 1 1/2 lightly still runs but don't think he has had the car out for the past couple years.

I have heard that it is a big no-no. but i have never managed to mix them up.

It's not advisable ofcourse, but on the other hand, I'm currently running a stroker motor with a USED hydraulic cam, on which I put USED Solid lifters. (Don't ask, I have some redneck moments I guess )
I poured a bottle of CompCams cam break-in lube along with the API SJ-rated oil, so plenty of zinc to go along.

Been racking up the miles on this motor without any problems at all.
I know I've been playing with 'fire', but I like to think I got lucky here.

I've got a roller cam waiting on the shelf for this motor, so the "McGyver-cam" comes out in the near future anyway.

Thanks for the advice, looks like I will use plenty of lube and light springs... unless maybe this is a good time for a new cam. BP.

ive done it so id say that is a myth
if youre one of those organized freeks
then it matters
other wise the cam doesnt know what type of
lifter is running on it
exept roller
just like some people are so perinode
they want use the same came in diffrent motor
affraid the cam will go flat

Mark the top with a sharpie, turn the engine over, and watch for them to turn. If they don't, swap locations until they do. Thanks to Jericogtx for that tip

I've bought used cams that the lifters were suppose to be in order but who knows. Didn't have a problem but I did re-break the cam/liters in with light springs.

No myth. Never, ever, ever run unmatched flat tappet lifters on an already run. If it worked in the past for people, you all got lucky. Period. Buy a new set of lifters, remove the inners as mentioned, do the regular break in procedure after verifying they rotate in the bores, and you're good. It's not worth risking the entire engine for a set of lifters.

totally wrong
done to many
i have even done the solid to a hyd thing couple times as well its just natural science
cam doesnt know all it knows is to turn & lift
and i dont do that lighter spring breakin thing either!!
if the new cam needs to be broken in it
needs to see the pressure in order to break in
just my opinon but never had a cam down either
if what you do works and you dont have any cams go down keep doing what you do !! it works
just alot more monie