5.12 cam and stock valve springs?

A used cam is fine, just check for any obvious damage where the lifter rides on the cam lobes.

That type of lift is pushing it for stock valve springs. Especially old valve springs...

The stock cam has .444" lift, so the jump from the F cam is really pushing it.

I would advise against using stock springs.

Good Luck!

I would also Advice to use New Springs.

.500' lift is about the Maximum I would go, without changing the Valve Springs, because many people have told me its not necessary at that level. With .512' lift, like the F303 and its Suitable RPM Range, I would definitely swap in a Decent Set of Valvesprings (.550' lift) to stay away from Valve float and some wrecked Valve's in the Process. Just my oppinion. I didnt Switch mine out, but I went with alittle Milder Cam right under .500lift So saved a Few Dollars in the long run.

always get the springs recommended for the cam. I used an E-303, which is .498 lift, and it wore out my stock springs after maybe 20,000 miles.

i just installed a custom cam with .514 lift. it was recommended by crower who ground my cam to have at least 115 lb seat pressure and 290 open pressure.stock springs dont come close. it cost me $200 to have a machine shop machine off the boss under the stock springs to install double springs,reatiners and locks which i purchased from the machine shop and were included in the $200 price. i did buy $160 worth of springs, retainers and locks from jegs but after checking with the machine shop he told me he could machine what i needed and install the new springs keepers and locks for the $200 i returned what i purchased from jegs...i wish i called the machine shop first....you will need double springs and machining to do the job right...just get the recommended valve seat and open pressure from the cam manufacturer and get in touch with your machine shop they should be able to tell you the cheapest and best route possible...

The used cam will be fine however you will need to change out those springs. I just put an X cam in and used Crane Springs part #44308-1 they are $116.00 in Summit and are a direct replacement. They work great and are good to .550 lift you can be into a new cam and springs for $250.00.....Sweet