Since this is going to be my first cam swap I figured I would ask what trouble spots I might run into on my 68 302 J-code.
Any tricks to the swap that would make things easier? I know I should spin her to TDC on #1 cylinder but other then that…
What would you replace (besides the cam, lifters and timing set that came in the kit) during re-assembly?
Thanks in advance.
valve springs!!! do some research and check your CAM lift against what the stock springs will allow … TRUST ME … the little extra you spend on springs will save you headaches later!! ALSO (and this is more curiosity than any thing else) what CAM specs are you looking at ??
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=791&sb=2 I wanted a cam that was slightly hotter then stock but would use the stock springs.
how many miles are on your current build? That cam will be fine with stock springs and keepers and rockers but if your engine has a ton of miles on it then those components should be replaced as well. Depending on what miles are, a valve job wouldn’t be a bad bet. Probably needs done anyway to get the hardened seats if not already done somewhere along the way.
Number of miles are unknown. Heads and valley looked very clean when I had it apart earlier in the year. I probably shouldn’t be a cheapskate and go ahead and spend the $200 getting the heads done after I buy the Comp springs.
I agree new springs are a must. Also a good idea to check them for load as well with a spring checker. Any good machine shop can do that for you as well. Check them at both open and closed height against their advertised load. Five lbs variable is acceptable, but 10 lbs is not. You would be surprised how springs vary. Not very good quality control especially in aftermarket.
Also check your cam bearings. Especially number one as it receives more load from the timing chain. Roll your push tubes across the counter top to make sure they are all straight. Use some good Molly lube on the cam lobes and lifters for break-in.
If you put in a new set of springs it is a good idea to either pin your studs or put in screw in instead of pressed in studs. I found out the hard way on this one.
Randy Feuillerat
I used that same cam in my car. Did not change anything in the heads and so far all good. The lift is not a whole lot more than stock. Hope you have the right gears i lost a lot of low end power with a 2:75 rear end. Once the RPM’s are up works real good. Break it in right with the additive you should be alright. Oh and nothing wrong with doing all the other stuff if you got the cash.
Thanks for the customer feedback. I’m running 3.0 gears so it should be a bit better. You have a stick shift?
Having done this for the first time last year and learned the hard way !! 
I’d definitely change the valve springs.
When it’s rebuilt, check the pushrod lengths
With a Comp on a 302, check the firing order. A lot of them use the 351 firing order.
You want that baby to fire up pretty much straight away to follow the break in procedure.
Use PLENTY cam lube on re-assembly, and throw some break in additive into the oil to run it in.
Running it in with fresh oil won’t hurt, some folks advise to fill over the max to ensure plenty oil splashes onto the cam.
Run it at 2-2500+ rpm for at least 20-25 mins. If you have to switch off at any time, bring the rpm straigh back up, don’t let it idle at all during break in.
I lost a few lobes on my Thumpr cam (also by Comp) even despite breaking it in properly and I’ve heard a few other similar stories of Comp cams failing even despite proper break-in running. They use “improper installation” as a get-out clause on the warranty. 
it seems they’ve checked the problem now, rumours were that they had a batch of substandard recycled metal, but I don’t know if this is true or not.
On the bright side, using the old timing gear as a base, my nice new Thumpr can makes a nice $200 lamp standard. 
“some folks advise to fill over the max to ensure plenty oil splashes onto the cam”
Don’t overfill! The majority of the lubrication on the cam lobes come from the oil exiting the cam bearings. If you overfill the crankcase all you’re doing is putting the level closer to the crankshaft. The crankshaft will pickup the added oil and sling it around and add lots of air to it when it goes back into the oil pan. Now instead of having just oil in your oiling system, you just added a bunch of extra air. Now instead of having just oil exiting the cam bearings you now have a lot of air mixed in. Which in effect, reduces the lucubration of the cam lobes.