360 Block/401 Crank

[Tigger]

Getting a crank kit with the crank is almost as cheap as getting a crank turned, what are the pros and cons of putting a 401 crank in a 360 block that will be .040 over. which rods would you use the 360 or the 401? I am used to building the I6 Strokers but the V8 stuff is new.

discuss :-|

[Lifted79CJ7]

Well, I remember the moderator at www.Froadin.com had some info on this, and here is what I borrowed from his tech site:

"Any crank will fit into any block.
(Clearancing required to put 401 or 390 cranks in the 290 or 304 blocks)"

"A 401 crank in a 360 block is a good combo. It ressembles the Chevy 383 set-up. But a little bigger, 385, without boring, and 390 at .030 over. But needs special made pistons or bushed pin holes in the rods."

"The various overbore capabilities allow the use of many different pistons.
ie. Chevy 305 pistons fit in a 304 block to give you 311 ci. Chevy 400 pistons fit in a 360 block, and while this only gives you 367.7 ci., this combination with a 401 crank gives you a 393.4 ci. Many more combinations are availible. Please note that these combos are with machine work, and are not just drop in."

I would have posted the links, but they all come up the same. I hope this helps!
Jack

[Tigger]

That link is where I got the idea from. Figured some of the AMC V8 Guru's could shed more light on the details and if its a good idea or not.

[diddycj5]

I was just starting to look into the same thing... I have 2 360 blocks for one rebuild project but like the idea of stroking it and having a fordged crank. What is different about the pistons that you can't use 401 crank/rods & 360 pistons? Aren't 401 rods fordged also?

[jeepsr4ever]

you can build a AMC 385 that way or a wild stroked 360 depending if you stay with the stock strok of the 401 crank

[Tigger]

Do you have to go with custom pistons or would a good set of 360 pistons. Do you use the 360 or the 401 rods?

[Tigger]

:-| hmmmm no answers for my questions.... come awn guys help me make a V8 stroker.

[Lifted79CJ7]

Simple, just measure the rods, pistons and crank and do the math. I think you have to get custom pistons. I remember reading that somewhere so that you can clear the heads. I could be wrong, though. I would say use 401 rods since they are forged. If they don't fit, then drink lots of beer. I know none of this really helps right now, but I will see what I can dig up tomorrow for ya.

[Tigger]

A 360 with a 401 crank and .040 overbore works out to be a 392 Stroker. :?

I don't have 401 pistons to measure and compare to 360's, can someone help me with that information?

Connecting Rod Length:
360 - 5.875
401 - 5.858
Difference - 0.017 (401 being less)

I know in the 4.7L I6 Stroker you use the shorter 4.2 rods with the larger stroke of the 4.2 crank so you don't have clearance problems with the head as well as compression that is way out of sight and you use stock 4.0 pistons (you can dish them to lower compression even more). I am thinking it would be the same with the 360, use 401 Crank/Rods and standard 360 compression overbore pistions. I was told with a 4.7L Stroker that you had to use custom pistons also but never had to using the 4.2 crank/rods

Deck height:
360 - 9.208
401 - 9.208

Cylinder head volume:
360 - 5.792 cc
401 - 5.792 cc

Deck clearance:
360 - 0.012
401 - 0.002
Difference - 0.010 (401 being less)
If you take the connecting rod length difference Deck clearance becomes a .007 difference, making the Deck Clearance 0.009 closer to stock 360.

[FSJnovice]

=D> How deep in the hole will the piston be? How much compression will you have? Sounds good and looks like it will work, mock it up and post pics. Just to see how the reciprocating assembly actually moves with or without binding remember pics. :t: :mrgreen:

[Tigger]

CR is my big concern I don't want to have to run AVGAS to make this thing run right. Also clearances are a concern... If I can get my hands on a 401 Crank/rods I will do a mock up. I don't want to spend a whole lot on the 401 crank/rods and then not be able to use it or lose money on it selling it. I have some pistons to use.... hell I could even do the clearance checks before I take the motor apart, just put in the 401 crank on 360 rods and do the checks. the pull a few pistons and put the piston on a 401 rod and do the same checks.

[Lifted79CJ7]

MC????? Come on, we know you have this stuff laying around!! Help a brother out!!

[Tigger]

Well looking on the AMCFORUM, its possible to make a 360 stroker but custom pistons are a must and if using the 401 Crank/Rods I will have to notch the lower part of the cylinder for clearance.

[Lifted79CJ7]

Shooo, with all that time and money, I'd rather build a twin turbo'd 360. Bet that would be one mean machine!

[Tigger]

Yeah that is what I am thinking also...... So I guess back to the original plan of a 360, .040 over, 9.5:1 Compression, edelbrock performer intake, edelbrock 1406 carb, Summit 8600 Cam/timing gears, oiling mods... etc....

When I have some extra time and money I will do the 360 Stroker...

[jimjeepn]

I just happen to be working on this very subject and here is what I've come up with so far. Let me know what yenz think.

-360 block bored 0.040 over

-401 crank offset ground to 3.80 stroke and 2.00 rod journal size

-Small journal 5.7" SB che*y rods with wrist pin end honed out to AMC size (0.927 to 1.00)

-Stock +0.040 360 pistons

This all adds up to;

3.8 stroke
4.12 bore
9.208 deck height
5.7 rod length
1.58 piston compression height
58cc combustion chamber
0.045 head gasket thickness
20cc? piston volume (your size may differ)
0.028 piston to deck clearance
9.78 to 1 compression ratio
405.283ci displacement

Have I left anything out? Let me know :-|

[timboamx]

I'm a computer geek by trade in the Navy, so I don't know all the in's & out's of what my machinest is fixin to do, since I'm still learning, but here is what I do know so far (except I can't find my notes...so its all from memory right now).

- 360 Block
- Stock heads (ported, will be flow matched @ a later time)
- 390 Crank
- 401 pistons (will be shaved)
- connecting rods (not custom) but form someone like chevy or maybe it was mopar
- he's also making some changes to the heads, different valves & something else.
- He's also doing something with the oil plumbing for the rear mains & to help lubing up the distributer gear or something.

- My machinest has done more than a handfull of the 360 stroker projects with the 390 & 401 crank Using AMC pistons. (as a matter of fact he just completed one...360 block 401 crank SBC aluminum rods & it hauls butt..pistons unknown). Though for some reason he does prefer to use the 390 crank...

- I'm trying to get permission from him to photograph the process and get the information from him about the complet process (ie what connecting rods, how much has to be shaved, how much grinding etc)

- Will keep you updated as the process progresses.... droping off the block thursday..... (yes he's already checked the block for thickness & what ever else he checked too). The block wont be done anytime soon though..... Told him I dont need it til around Feb... (Income tax return time)... but I droppin $1800.00 on to get the process started....

[jeepsr4ever]

timboamx

Welcome aboard!

Good stuff that stroker your going to love it!!

[jimjeepn]

timboamx,

Hey swabbie!

Whatcha putin that beast in?

Hope you trust yer builder like we trust you with our freedom!

THANKS FOR BEING THERE! :sa:

[timboamx]

I sure do.... He use to race and held a couple of records for the Hornet straight 6 2-bbl.... also he did some work on the "Booth" Gremlin.. His buddy own's it now (right up the road from me apparently)... and he's also lookin it over too. He's been rappin stuff off about AMC and their engines since I met him.


Tim