my 401 build

just1977cj

I just picked up a 401 for my cj5 build I am doing. I will be dropping it off at the machine shop to have everything checked and work done if needed. I would like to get it back as a short block. The jeep will be used alot offroad climbing around and in the mud bogs. I have a T-18 that I will be using also. I was hoping on going with something in the 10 to 1 compression wise ( want to be able to run it off premium pump gas). Should I bother with any oiling mods while its at the machine shop??? I really need advise on what cam to go with. I will be running headers not sure which ones as of what now, I have a new performer intake that I was gonna use and a 770 holley truck avenger carb. So Im kinda stumped on what cam to go with it shouldnt see a whole lot of high rpm's I would think but dont want it to fall on its face to early. Was hoping for the motor to end up in the 400 horse and close to 500 tq range. It came with a flywheel that looks to be in good shape but I will drop that off with the engine also to be checked. The timing cover it came with is junk so I was going to use the one off my 304 that looks to be in good shape. I will need to buy a balancer as it didnt come with one, any recommendations? Anything else I am forgetting?

jeepsr4ever

Phwew where to start! First off I would install smaller hole cam bearings right off the bat. This will help set your hot idle pressure for years to come. This and a deeper more capacity oil pump shold be all you need. For cams I wouldnt look any further than a summit K8600...they are cheap and work well in a 401 with a 4bbl and a nice carb like the one you are planning on using. Also check your 304 timing cover!!! There is nothing worse than rebuilding a motor only to have its life cut short by using a worn timing cover! I have built a couple handfulls of 401's to do EXACTLY what you plan on using them for so if you hit any walls be sure to post up, more than happy to help! :t: Oh and balancer you can check ebay or if you wnat to go for the best we sell a SFI balancer that rocks and has removable weights if you ever go crazy with that 401!

just1977cj

where would I go about getting the smaller hole bearings from? I am trying to get everything ready for the machine shop. Also a new timing cover, I think I may just go that route. Do you think the summit 8601 cam is to much?

73hornut

just1977cj wrote
where would I go about getting the smaller hole bearings from? I am trying to get everything ready for the machine shop. Also a new timing cover, I think I may just go that route. Do you think the summit 8601 cam is to much?

Drill and champher the ones you get in the kit. 1/8 hole for all but the first(front) that feeds the dizzy. Make sure the first has 360 degree groove.

just1977cj

where would I find valve springs to match the 8600 or 8601 cam from

ironman_gq

you can also get small hole bearings in the store here as well as timing covers and many other goodies (would be more but MC's shop is taking their time :wink: )

just1977cj

Well I will be dropping the engine off at the machine shop sat. I spoke to them today for alittle about what I wanted and I have had past engines done by them before and was pleased. The only thing I am slightly worried about is they dont have a ton of experience with v8 amc motors. What info do I need to pass along. I was assured by them that I would have no problems and would be happy with the results. I will be getting the engine back as a short block so all I have to do is throw the timing cover, fuel pump, water pump, intake, and carb on and I will be set. Excitement is really starting to kick in.

ironman_gq

make sure they put the oil galley plugs in all the holes and that one of the ones on the front is shorter (cant remember which) if the wrong one is put in it will partially block the oil passage. make sure the lifters arent loose in their bores and make sure to use the valley pan under the intake. Upgrade the ignition!! factory ignition sucks I would go for an HEI unit from MC here.

Dusty

current build up i am working on for a 401 since mine is sucking hind tit lately 8.5:1 CR cast pistons (may re ring stock std bore pistons despite the cylinder wall taper) stock 58 cc heads Cam will be lunati: Advertised Duration (Int/Exh): 256/262 Duration @ .050 (Int/Exh): 213/220 Gross Valve Lift (Int/Exh): .484/.507 LSA/ICL: 112/108 performer intake Fuel supply will be howel injection with holley 670 TBI unit. HEI distributor from MC Stock non smog exhaust manifolds with bumps ground out, i was running single 2.5" but probably will change to dual 2.5" I am running 4.56 gears i wish and prbably will change to 4.10's with my 35's in my cj7 with a t-18 smaller cam than i have run in previous applications but i am trying to tame this motor down in hopes of making it more Fuel injection / 500 rpm idle & high vacum friendly. use this info as you see fit. results to be posted in about a month. FYI i do run ARP rod bolts, headbolts (which require you to grind the manifolds) and ARP bolts or studs on the bottom end. regardless of engine build, it's peace of mind knowing that something simple isnt going to come apart I am looking get into a number close to 350 hp / 440 ft/lbs with 400 ft/lbs +/- at or close to 2000 rpm. Low rpm idle is more important to me on this build than builds i have done before.