401 Build Q: Stock 401 crank and connecting rod strength

[Jay-ten]

I am new to the forum and have a 401 build question.

I am preparing to rebuild a 401 I recently picked up. I am targeting low end torque first and horses second for off-road fun.

I was wondering if anyone has a good estimate of what kind of power and torque the stock 401 forged crank and connecting rods are capable of?
I would like to reuse these, but need to know their limits before I decide.

Also, does anyone have any feel for torque/horsepower vs. $.
I keep remembering the old race adage "Horsepower costs money - how fast do you want to go?"

So if someone has an idea of torque/HP vs build cost I'd really appreciate that info.

I have only rebuilt three engines and only to get them back on the road. I have never built something with specific use and design targets - so I may ask some stupid/ignorant/newbie questions without warning.
Thanks

[ironman_gq]

not sure on how much they can handle but 400hp should be no problem for em if they are in good condition. As for your build a good cam and intake witht the right carb and maybe a little prt matching and a slight bump in compression should get you into the 300's with no problem possibly even deep into the 300's. If you do a full rebuild with a 30 over bore and get the block decked to keep quench where it should be and have the heads shaved a little you should be very happy with the motor

[fuzz401]

balance and polish the rods they will take 7000 rpm all day

[jeepsr4ever]

After nitriding the stock crank can handle over 800hp. If you plan on that number or above then you will be doing the mag checking for microcracks and a quick prayer before assembly. :?:

[tufcj]

There have been several build-ups of 401s lately.

Here's one: http://www.carcraft.com/techarticles/116_0503_amc_brute_engines/index.html

Bob
tufcj

[Jay-ten]

Has anyone used Desktop Dyno or Dyno 2000 that they could recommend a package?

[tufcj]

For torque, keep the compression in the 9:1 range, cam around .480-.500 lift and 110-112 lobe separation. Shot peen the rods and have the rotating assembly balanced, and it will live a long life at normal RPMs.

AMC engines really like to breathe, so spend any extra money on a good 3 angle valve job and at least pocket porting of the heads.

Look in the e-store here and get the modified cam bearings to get a little more oil to the mains. Make sure the oil pump housing is still within spec, and replace if the clearance is too high.

A 400 HP, 500 ft/lb 401 isn't hard to achieve.

Bob
tufcj