Stock cam specs - 1974 401

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tigger4x
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Stock cam specs - 1974 401

Post by tigger4x »

Unfortunately, the olJeep(dot)com website is down, so here I am :-? Does anyone have the specs for the OEM cam that was in the 1974 401 engine?

EDIT : Ryan from BJs OffRoad let me know that it's a Chrome browser issue :banghead:

I need to order a cam/lifter kit and am going to go with OEM specs at this time. BJs has the Comp Cams 260H and I believe that's the one. Does this look stock?

Specifications:
Advertised duration: 260 intake/ 260 exhaust
Duration at .050 in. cam lift: 212 intake / 212 exhaust
Gross valve lift: .447 in. intake / .447 in. exhaust
Lobe separation: 110 degrees
Basic rpm range: 1,200 to 5,200
Good low end torque. Strong mid-range power. Excellent for towing or performance.
Recommended compression ratio: 8:1 to 9.5:1

I contemplated an "RV" cam, the Comp Cams 268H, but it would entail pulling the heads to do the valve springs. I'll do that when I find a 258/4.2 or a 360 and convert it Iverson to propane. For now I just want to be sure the 260H is going to be the right one. This is a basic refresh along with the timing chain kit and swapping an EB 2131 intake.
Last edited by tigger4x on Tue Jun 07, 2022 12:35 pm, edited 1 time in total.
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devildog80
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Re: Stock cam specs - 1974 401

Post by devildog80 »

I have the 401 in mine too, but not sure what year, as the data plate is missing off the valve cover.

Is there another way to narrow it down, as till now, I have not found another way to identify year?
'81 CJ5 Base, 258 I6, MC2100, T176 4 spd, 300 TC, D30 Front NT, 3.31, 2-Piece AMC 20 rear NT, 3.31, 4" high arc spring lift
'84 Grand Wagoneer, 401 V8 (.030 over), MC2150 HA Comp, 727 auto, Selec-trac NP229, AMC 20 REAR - D44 FRONT - WT 3.31, 4" high arc spring lift
Rather be driving, than waiting to be modified
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Re: Stock cam specs - 1974 401

Post by tigger4x »

I'm not sure how to date the engine itself. IIRC the 401 was available from '72 - '78. I don't know if the cam/lifters varied at all or if they used the same profile the whole time.

This is some of the info about the kit itself, but nothing on if it's Stock, RV, Performance, Torque, etc.

Fits:1972-1983 Wagoneer
Fits:1984-1991 Grand Wagoneer
Fits:1974-1983 Cherokee
Fits:1972-1988 J-trucks
Models:All with AMC V8 Engines
Recommended for 304, 360 & 401 V8's
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tgreese
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Re: Stock cam specs - 1974 401

Post by tgreese »

The 401 was available in these Jeeps 1974-78. The only models that got it were these wagons and trucks. All the 401s in Jeeps used the same cam, Jeep PN 8121156. Crown sells a camshaft under that part number; maybe others do too.

The Summit Racing web site shows some numbers for that part. https://www.summitracing.com/parts/CWA- ... 6#overview
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devildog80
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Re: Stock cam specs - 1974 401

Post by devildog80 »

The data tag in the engine bay and PO verified, mine came with the 360 stock, and PO replaced it with a 401 he had rebuilt. I have the receipts, but nothing indicates what year the 401 is, or where it came from.
I have found the earlier ones were stock with more horses than the later ones.
'81 CJ5 Base, 258 I6, MC2100, T176 4 spd, 300 TC, D30 Front NT, 3.31, 2-Piece AMC 20 rear NT, 3.31, 4" high arc spring lift
'84 Grand Wagoneer, 401 V8 (.030 over), MC2150 HA Comp, 727 auto, Selec-trac NP229, AMC 20 REAR - D44 FRONT - WT 3.31, 4" high arc spring lift
Rather be driving, than waiting to be modified
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Stuka
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Re: Stock cam specs - 1974 401

Post by Stuka »

devildog80 wrote: Tue Jun 07, 2022 1:32 pm The data tag in the engine bay and PO verified, mine came with the 360 stock, and PO replaced it with a 401 he had rebuilt. I have the receipts, but nothing indicates what year the 401 is, or where it came from.
I have found the earlier ones were stock with more horses than the later ones.
The way HP was rated changed in '72. Engines moved from Gross to SAE Net. Which is why HP numbers fell off in '72 compared to '71.

Earlier heads (Only '71 for 401's afaik) had smaller combustion chambers, which resulted in higher compression.

ALL Jeep 401's are low compression engines.
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Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ
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Re: Stock cam specs - 1974 401

Post by tigger4x »

I called the tech line at Comp Cams and was told that the 252H is the "stock" cam, and that the 260H is what would be known as an "RV" cam. While it is not necessary to change out the springs, it is advisable replace them. While mine do not have a lot of miles on them they are the stock springs from 1974. The tech said that with them being "softer" it will help with the break in of the new cam. He also suggested that I use Driven brand assembly grease rather than the typical assembly lube that comes with the cam. The usual stuff is great for installation and breaking in the cam pretty much in the same day as it tends to run. The Driven Racing assembly grease, aka Joe Gibbs Racing, will stick with the components for a while and while the engine comes up to temp; it will slowly meld into the break in oil. He also really suggested to use the same brand of break in oil at full capacity for optimal cam condition.

Now it's back to waiting on the parts to ship! :-bd
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