How much lift?

[RustyJeep]

How much lift can my cam have before it starts to kiss my pistons? This would be on a relatively stock 401 with EFI, I assume stock for now....not actually torn it down yet to mic everything out. Engle's 5054-H and 5056-H cams look interesting to me, but I need to know more. I want low/mid grunt, but I also like to wind out my motor....so I am teetering in the middle. I have also been looking at the 276HDP Crower grind. I just don't really feel like doing this job twice if I don't like the performance...so.....

This would go in my 73 J4000 with a T18 4 speed.

[jeepsr4ever]

Rusty here is my experience

engle-junk (wrong profile)
comp cams-junk (bad grind)
Summit (good for low and mid 8600-8601)
Crower (?)

If you are to run a low end cam dont worry about the valves hitting, your valves hit when you advance your timing gears too much.

[RustyJeep]

Well that's the thing. I don't think I want the summit K8600 in my 401. I had it in my 360 and it seemd to run out of steam...or maybe the rest of my stuff was...lol...I like to bounce it off my rev limiter sometimes, especially in the mud. But I tow also. Also, I don't want to get one of Summit's "bad cams" and have my 401 spit it back at me. I don't like gambles..and this whole cam choosing bit is one gamble that is wearing on me. It sounds like it from my ramblings doesn't it? :) How's the K8601 work out in a mild build?

[jeepsr4ever]

Rusty, I run a 8601 in a 401 in my 77

9.6-1
502 heads
R4B intake
headers
8601

Friggen rocks up to 6K

[RustyJeep]

hmmm...tempting :) I wonder what it'd do with stock compression? I don't want to have to buy new pistons if I don't need to. But, we'll see what my findings come to when I tear into it.

just to shed more light on the subject as of now
Mild build 401
port matched heads
performer intake, Holley projection
MSD6al, TFI
manifolds to single 3"(tentative)

Most of the stuff is already in the Jeep from the 360

[jeepsr4ever]

Rusty,


401 cast pistons are notorious......I say notorious for developing cracks on the skirt and on the diameter of the wrist pin. Have them pistons checked out. Once I had a set I thought could be reused, didnt see any cracks. Well I cleaned them up and every stinking one was cracked. If you have a 401 (stock or rebuilt with cast) that saw some high R's then chances are you may need new pistons. For cast expect around $300 for a set for hyperutectics around $400 and for forgings aroun 600.

[RustyJeep]

Ok, one more question....
What if i were to use rhodes lifters with the k8601. In my mind, that would get me some more low end grunt out of the cam yet still have it up top too. Does anyone have any thoughts/experiences with them?
OR, will the k8601 be good enough to stand on it's own and have enough low end grunt wand halfway decent idling characteristics for when i am crawling?

[newt]

I've heard nothing good about the Projection. Are you already running it on the 360? Also, I've been told it won't be able to flow enough to keep a mildly built 401 happy at 4000+ rpm.

[RustyJeep]

Yes the projection has been on the 360 for over a year. I love it, but it's a tinkerer's setup. Not an install and go type. I was debating the flow issue...what do people usually run for carbs on their 401's? 750's?

[jeepsr4ever]

750 is right over here or a 850 double pumper