401 Build.. NEED HELP!!!!!! Mystery cam problem.

Revelc

I got a 401 on craigslist for $2,000 recently ( because my 360 was a dog and finally started knocking ) Its a fresh rebuild. Never been run. WHAT I GOT 1976 401 Block Cleaned up 502 heads New valves and springs .30 over 9.5:1 Cast plugs Race hone... Whatever that is. 5 angle valve job Mystery cam that only has CWC and random numbers all over the cam one possible part number is 3234 - 029 New timing cover amyways.... The guy was going to put it in his Jeep and built it to be a hot little motor... or so he says. He said it has a high lift, but streetable cam and that id need a stall converter. WHAT ITS FOR I will be putting it to work in my DD that will see a lot of Gold Camp Road and light trails.... if I can help it. So a hot cam wont jive with low rpm crawling. I want grunt and plenty of it. 500-5000RPM And something that will get the old girl down the interstate at 80 mph Occasionally pulling a stock trailer with a few cows 85 Wag 31" Mt's locked 3.35 gears TF727 Aftermarket NP transfer case Holley TA 670 WITH THIS STUFF It also will be getting my Slightly used.. Summit Aluminum rad. High flow coolant pump Eedlbrock performer intake MSD Matched gears, Dizzy, Wires, and Coil And some free Edelbrock chrome bling. Stock manifolds with single 2.5" straight pipe ( which Ill be switching to duals eventually ) THE DELIMMA If we cant find the specs out for my cam I dont want to run it. I have it sitting in my dorm room floor as we speak and I dont want to go through another Cam swap because I dont have a garage. I am a missionary attending school in Colorado Springs so I cant afford to buy anything other than a Cam and accompanying gaskets, break in oil, etc.. I also am really worried about my selection because the Springs are brand new but I dont know their specs. I want to run an XE262H (supposedly 344HP 454Ft/Lbs according to cam quest) for the setup. Maybe a XE256H ( with 5 less hp but +2Ft/Lbs...but I dont want to sell this thing short. I am open to other cams as long as you dont think they will break valve springs within 20k miles at which point I should be able to replace the springs. They are 1.4 outer diameter according to my micrometer. I wont be ripping RPM's past 5k I will be ordering my cam next week so I hope some of the 401 guys have time to chime in and help a newbie out. Sincerely ,Clueless

Revelc

Come on guys, I tried asking about this issue in Jeepforum and I didnt get much help. I have also been pouring over threads but nobody talks about the largest lift cam they have run with possibly stock spec springs.

jeepsr4ever

256 is a pile of crap for a 401 the lift isnt there for any power over 1800rpm. There is a crower cam that trumps the 256 but I dont have the specs in front of me (its the weekend shop isnt open and I am typing this at the dinner table with a 15 month old throwing spaghetti at me)

tufcj

The issue is if you're running stock guides and valve seals. At about .500 lift, the valve spring retainer will smash the stock valve seal against the top of the guide. If your heads have been machined for aftermarket positive seals, you can probably get around .580 before you get to a coil bind on your springs. I would never go with that much lift on a stock spring. For an off-road 401, I'd keep lift in the .475-.500" range, LSA at 110. Bob tufcj

Revelc

Well thank both of you for your help. I looked at the Crower site, the custom grinds are not much more than the EXTREME cam and lifter kits from Comp. Maybe I should go that route since I already have new lifters anyways. It looks like I am going to have to bite the bullet and change the springs after all. Or are you saying the valve seals and guides will interfere at anything over .500 but the springs are okay? I have never done head work before so I am a little hesitant/worried about it. If you guys think a custom grind is over kill for my application I'm open to suggestions.

tufcj

The stock spec springs are OK for lifts under .500". Most cam manufacturers have a recommended spring for their cams, and I usually use their suggestion just for the longevity of the lifters and cam. I like Crower cams. AMC engines seem to like the split lift/split duration. I'm running one in my AMX and in the engine I'm building for my Rogue. The only engine I've ever lost a cam lobe on was built (per the owner) with mismatched parts. I ended up rebuilding it a second time less than 2000 miles later with a matched set. Didn't hurt my feelings a bit to charge him a second time for arguing with me on the first build. Bob tufcj

Revelc

Okay that is a little bit of a relief. And for all I know these are not stock springs I just cant identify them or the cam that was in already. When you say mismatched parts do you mean the cam and lifters were different makes or the springs cam and lifter were all different?

http://www.crower.com/camshafts/amc/290-304-343-360-5-9l-390-401/amc-290-401-compu-pro-hydraulic-cam-276-hdp.html

This cam looks like it doesnt have too high of a power band but the lift isnt very big.

http://www.crower.com/camshafts/amc/290-304-343-360-5-9l-390-401/amc-290-401-power-beast-hydraulic-cam-280hdp.html

This one also looks nice but I dont want to run either if they are too big for the 401. I want to have lots of low end power.

Thank you again for your insight guys.

jeepsr4ever

With a camshaft like that what it is attempting to do is build compression with an emphasis on a short backpressure. The small duration at .050 LSA at 110 or 112 and a lift not to exceed .495 will work well.

tufcj

For a 401, I'd go with the first one you listed. If it was a smaller displacement, I'd go with the second. All in all, I like the cam, lifters, and springs to all be from the same manufacturer. Lifters are the least critical, but recommended spring pressures of the cam manufacturer should be followed. Too lite a spring, valve float, too heavy, flat lobes. Bob tufcj

Revelc

So I guess that rules out the comp XE262 because it's exhaust lift is .500 . I guess I'll give the guys at crower a call and go with something with a managable lift and a lobe sep of 110. All of the cams have 112 or 108 so I'd need a custom grind.

jeepsr4ever

You have 9.5-1 compression you have to be carefull which cam you use. Your dynamic compression may require premium if you dont run some quick numbers. Go here http://www.kb-silvolite.com/calc.php?action=comp and put in your cam data.

Revelc

I didnt build it so I dont know specifics. So I dont know what my dynamic compression would be. I wish I had a fellow Jeeper out here in Colorado springs with a brain to pick ( and a cherry picker would be nice too ).

This cam looks promising saying it works best with 9.5:1

AMC - 401
Performance level 2 - Power Compu-Pro - These cams provide excellent low end and mid-range power and extended rpm range for spirited
street and off-road driving.
INT/EXH - Dur @ .050” Lift: 210°/220° RR: 1.6/1.6 Gross Lift: .450”/.475” LSA: 112° RPM: 1500 to 4000 Redline: 4500

http://www.crower.com/amc-290-401-compu-pro-hydraulic-cam-270-hdp.html

I think it will do fine if I read the description correctly. With the torque of a 9.5:1 401 I would think I wouldnt need a stall converter with this cam.

jeepsr4ever

That performance level 2 cam would work well with a Edelbrock carb and performer intake. Or a vaccum secondary Holley.

Revelc

Thank you guys for your help. Ill be placing my order in the next few days. If you dont mind one more question, how much hp and torque can I expect with this set up?

jeepsr4ever

If your not pushing 350hp you dont have oil in the pan..HA!

Revelc

jeepsr4ever;132439 wrote
If your not pushing 350hp you dont have oil in the pan..HA!

Oh man that wouldnt be funny.

I actually learned a leason when I was breaking in a new cam in my recently deceased 360. I started it up and heard lifter clatter. I had no oil pressure. I primed it with an old distributor and everything....

But what I didnt do was make sure the distributor was completely seated #-o

It was still meshing enough to run but wasnt engaging the pump.

From now on its check. Then triple check every detail. Because they will eat our lunch if we dont.

I think at 350 H.P. Ill be a lot happier with the new 401 over the anemic 360 it had before. Thank God all of those expensive aftermarket components are inter-changeable :occasion5:

What does it really take to squeeze out 400 ponies from these babies? I shouldnt be too far off in mods to get there... at least I hope.

I have the 670 Truck Avenger
Edelbrock Performer intake
MSD ignition
9.5:1
a little gasket matching and a 5 angle cut
with the above mentioned cam

Future plans are a 50 hp shot of juice and 2.5" duals or 3" pipes with no mufflers or cat.

What other mods can crest that number aside turbo/super/nitro?

Any one have destop dyno?

I would want to have a streetable cam without a big stall if it was imperative to swap out to get those numbers.

tufcj

400HP from a 401 isn't too hard. But for 4-wheeling, torque is the number you should be after, not HP. Big torque close to idle is what makes a Jeep move. In going for HP, you're going to sacrifice torque. It's a trade off, engines with big HP numbers usually have less torque (except turbo or blower), engines with big torque will have a little less HP. In drag racing, torque makes ET, HP makes MPH. The torquey car will come off the line harder but not have big MPH, the big HP car will be faster at the top end but be slower off the line.

Check out this article: http://www.carcraft.com/techarticles/116_0503_amc_brute_engines/viewall.html

Bob
tufcj

Revelc

I ordered the Crower cam 45241 INT/EXH - Dur @ .050” Lift: 212°/220° RR: 1.6/1.6 Gross Lift: .464”/.488” LSA: 112° RPM: 1500 to 4500 Redline: 5000 I previously posted about I got it in today and ITS THE EXACT CAM THAT I HAVE HAD SITTING ON MY DESK FOR WEEKS NOW!! I could have left the whole engine together and swapped it out by now :banghead: The part numbers are the exact same. I called to check the numbers just in case but the cam guys at Crower were all out for the week. Oh well, back in it goes. Just to confirm since I have this cash freed up for the return. I should not need a stall converter for this cam size with my specs right?

jeepsr4ever

!!!