401 build recipe ideas

[Grand_Wag_85]

Found a replacement motor for my J10 in the form of a 401, big thanks to Flint and Rstep!

401 will need a rebuild. What's a good build recipe in terms of camshafts etc? Likely going .030" over.

Also wondering about intake manifolds. How much of a noticiable difference is there between the Performer, TorkerII and RPM AirGap intakes? Not looking to build a racecar but some balls would be nice! Will be going fuel injection (TBI) instead of carburetor.

How about headers and exhaust?

[fulsizjeep]

Wow. 90 looks and no replies? Is everyone out living life or what?

This engine comes with a cam Sean. I have just about found all of the bits and pieces. OMG, I will be glad to get some space back downstairs. Will get you specs...


You may want to consider the 70 Machine heads for this recipe too.

[440sixpack]

I wouldn't use that much cam in a 4x4 unless it was a race machine.

a 260 duration is about all I'd do if you want good drivability . 270 would be max, I have a Comp 270 in one of my AMX's with a 390 and it would suck in a pickup. I used a Comp 260 in my 360 for my J10 and I like it.

Keep in mind compression is power and power needs octane. you need to decide what your goal is and how much you want to spend to get it, then how much you want to spend to feed it. this is where the build design begins.

[Grand_Wag_85]

Just took a look at the fine print on that cam, wow! This truck sees mild wheeling occasionally at best, it's mainly a pavement pounder.

That's an interesting tid-bit about octane and compression, never really gave it much thought. Ideally somewhere on the normal pump gas spectrum

[bigun]

Run it on Propane

[Grand_Wag_85]

Run it on Propane

I know you went this route on that theoretical rig you call Crom…..Which route did you go?

[babywag]

that is the “RV” grind aka edelbrock performer in above pic.
good cam for jeep and nowhere near a race cam lol

[fulsizjeep]

Thanks Tony. That is what I remember about the cam too.

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[fulsizjeep]

Sean - FYI

This does not need to be bored nor the crank turned. It will be a straight up Standard size 401. Comes with new Standard rings, rod bearings, crank bearings and cam bearings. There is also a new set of freeze plugs. Includes new Cloyes double roller timing chain set. Does not include cam and dizzy gear. I would have had machine shop dip the block, knock the glaze off cylinder walls, install cam bearings and recondition the heads. I recently picked up a timing cover from Roy at Ouray. The original had frozen bolts in it and was destroyed removing it.

Yeah?

[Grand_Wag_85]

Yeah!

[BCRAWLER]

Wanting to hear opinions on intakes. Thanx

[fulsizjeep]

Comes with factory square bore intake from a 73. I would run that or an Edelbrock Performer.

[440sixpack]

My bad, I guess I need to wear glasses more. that cam would work fine.

The performer is a good all around intake.

If you want to run regular gas don't worry too much about your build it's going to be pretty stock. which is fine .

[derf]

Factory manifolds aren't worth the weight. The Edelbrock performer is a good all-around manifold for daily driving.

[fulsizjeep]

I tend to disagree on the factory intake. Yeah, it is heavy. The smaller runners help produce more torque at lower rpms. One of the reasons I have an SP2P on my 401. It depends on what you are after. It was not meant for 5000 rpm runs in a Gremlin. You probably want an R4B for that.

[FSBOB]

Glad someone's talking about this. I've got a 401 I'm also looking to rebuild this fall. What I've read in this forum and around says mostly the same thing you guys have so far in this thread about cams and intake manifolds. I'm currently running sniper efi, msd ready-to-run ignition, edelbrock performer intake and headman headers. It mostly works well together but I did end up adding a 1" spacer between my throttle body and intake after installing the performer because I had issues. Turns out my throttle body needed a good cleaning but there are a lot of efi threads that talk about having issues with the efi not liking dual plane intakes. I'm still playing with mine so I haven't figured out anything positive or negative to add yet but it's something to consider.
However, I did drive to work one day with the hood off and could see smoke coming out of the breather every time I was at WOT hence the rebuild. What I'm wondering is for you guys who have rebuilt your 401 before where have you gotten your parts and things to look for? Also, I know the 401 was throttled back after 71. Did they do this by using dished pistons and lowering compression? I'd like to get more out of my engine without using a wild cam and losing vacuum at idle, so if you use higher compression pistons at what point do you think I'll have to run higher than 91 octane fuel? Any and all help is appreciated.
FYI, this is my daily driver but I am not worried about fuel economy/cost, mostly reliability... and the ability to do burnouts on 33's...

[fulsizjeep]

FSBOB, good questions but... This is Grand_Wag_85's thread about his 401 project. I am sure if you post up a new thread with your questions, informed members will reply. Thank You

[BCRAWLER]

Fsbob did bring up a point. Grand_wag_85 said earlier his intent is to run injection. Is he better of to run Torquer style manifold?

[Cecil14]

It has always been my understanding (someone correct me if I'm wrong) that there is no need for a dual plane intake with MPFI, or even really with TBI. The purpose of the dual plane intake was to help maintain vacuum to the carb, assisting mixing and equal distribution of air/fuel to each cylinder. With MPFI, that's all moot. The cylinders are going to drag in what they need to for air regardless, and fuel is provided in a metered fashion at each cylinder, already atomized.

I believe that most, if not all, modern engines run single plane intakes, but again I could be mistaken. I haven't ripped apart too many truly modern engines to that level.


aa


edit: spelling

[fulsizjeep]

I don't know about fuel injection, but if you use a Torker or Torker II intake, you will kill low end torque. 3500-7500 RPM

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