i'm planing a 406 build up in a month or so and i want to know if a stock 400 crank (not forged) and stock rods with ARP rod bolts would handle aprox 400hp and 450 ft lbs of torque. My friend says that it will hold up to that much power providing i use after market rod bolts. I just want all of your opinions. I dont have a whole lot of cash to spend cause i need to pay my car of as well
Thanx

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when the green flag drops the bull$hit stops

350,performer RPM intake ,650dp, 700r4, headers, 3inch exhast

 

yes

 

Ditto!! No problem.

 

i'll go a step farther and say use arp bolts. lot of people get hung up on forged cranks when there is a lot to be done to cast crank to increase it's chances of lasting, nitriding, polishing, hard chrome, radiusing the oil holes (well that's for the bearings) align honing. also using studs instead of main bolts will halp out.

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ICON Motorsports
1st & 3rd

 

I would not use the stock rods. You can get decent Eagle I-beam rods for around 200-300 bucks. 400s have extremely ****ty rod angles. 350 rods are 5.7 long as opposed to 5.565 for the 400. pistons are the same price and actually easier to find. 6 inch rods are usually the same price as the 5.7, but pistons are harder to find. i had the stock rods in my 406 the first year and it blew up at the track. i have the 6 inch H-beams now and they are great. it revs better and i went a full second faster without any other changes. just new rods and pistons. same cam, heads, everything. it will be well worth your money.

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88 S10
Dropped 3/4
Dart equipped 406
12.20 @ 115.25 mph

 

I would not use the stock rods. You can get decent Eagle I-beam rods for around 200-300 bucks. 400s have extremely ****ty rod angles. 350 rods are 5.7 long as opposed to 5.565 for the 400. pistons are the same price and actually easier to find. 6 inch rods are usually the same price as the 5.7, but pistons are harder to find. i had the stock rods in my 406 the first year and it blew up at the track. i have the 6 inch H-beams now and they are great. it revs better and i went a full second faster without any other changes. just new rods and pistons. same cam, heads, everything. it will be well worth your money.

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88 S10
Dropped 3/4
Dart equipped 406
12.20 @ 115.25 mph

 

From personal experience- you will have no problems. Get good rod bolts- I use ARPs.

I'd LOVE to have a set of 6" rods but the motor came with the stock 400 rods so i used them. I have many many 11s second nitrous passes on the motor and hundreds of 13 second n/a passes. Not to mention thousands of miles towing my boat.

THe motor is now losing ring control (it's got 6 years and 50K HARD miles on it!) and I am replacing it with a 383, jsut cause I want something different. But NEVER a bottom end problem.

 

406 S10,
I ahve a couple friends that have 383 and 406 S10's......got any pics of yours? Is 12.20's the best times you have? That's pretty quick!
I would like to hear more about yours.

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350 4 bolt main, Speed-O-Motive 383 stroker kit, re-sized rods ground for clearance,Hypereutectic pistons,9.8:1 compression,HPC Coated RPM intake, Speed Demon 750 cfm carb,World Products Sportsman II heads,2.02/1.60 valves, K-Motion springs, Comp Cam 1.6 roller rockers, Lunati adv.292/230@.050 with .512 lift,Crane pushrods,Proform HEI and MSD6A box,HPC coated 1 5/8 headers, 2.5" exhaust with 40 series mufflers,TH350 with B&M 3000 stall, Powertrax NoSlip Locker, 4.11 gears.

 

Hmmm.. a 1 sec reduction with just changing rod ratio? Same compression, ring design and everything? You went from a 5.565 to a 6.0?

In many cases, you can't get two identical pistons in 5.7 and 6 inch, let alone 5.565 to 6 inch. Your average dyno improvment going from a 5.7 to a 6 inch rod is less than 10 hp (all other things remaining the same). A 1 second reduction in the quarter is normally close to 100 hp.

And considering how much the rings are compressed to make room for the long rod, on a 400 that spends most of it's time below 6000, it is not worth it.

Eagle now makes a 5.7 inch I beam rod with cap screws and no H beam rod can be that light.

 

FWIW, I'm going to use the cast 400 crank that has been magnafluxed, polished, and radiused, along with 6-inch (660 grams)DES H-beam rods. and Lunati flat-top pistons (395 grams) in my .040 over 350 4-bolt main block. The crankshaft reconditioner has said the crank is fully capable of handling 450+ HP / 480 ft.lbs with no problems, assuming that the block is using main studs and is line bored.


A stock 5.7 inch LT4 PM rod weighs 600 grams, so my H-beams weigh 60 grams more per rod. However, the Lunati pistons, at 395 grams apiece, are a full 100 grams lighter than the equivilant piston for the shorter, lighter rod. Thus, I have a net savings of 40 grams per cylinder and a much stronger reciprocating assembly.


So that's the way I'm going.

By the way, I *do* have a set of .030 over forged TRW pistons hung on some 5.565" rods, along with a harmonic balancer and flexplate sitting here. Just add crankshaft and balancing, and viola! You have a 383. Anyone want them?? Low mileage parts. One of the TRW pistons (P/N 2244, I think) needs to be replaced as I dropped it on the floor while disassembling the engine.

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Daniel Burk
http://www.isthq.com/~dan/fcar.html
'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. PST suspension, Braided stainless brake lines, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Turbine Technologies 2500 stall converter, underdrive pulleys, Crane Hi-6 & more.
1.05g skidpad verified.
New best E/T! 14.039 at 100.82 MPH in 41 degree air at Stanton, Michigan.


[This message has been edited by ws6transam (edited December 18, 2000).]

 

I believe that they will. I have that exact combination (except mine isn't .030" over, it's still std bore so it'a a 401.6 not a 406); the rods have 130k miles on them without a failure.

I have this 400 short block in front of a 5-speed and under a pair of 186 heads, a Comp XR282HR roller, a Holley 800 CFM 4-barrel, etc.; I couldn't say for sure what the HP and torque are, but let's just say it eats L98 cars and Mustangs by several car lengths at the end of 2nd gear...

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"So many Mustangs, so little time..."

 

I have used ARP rob bolts&ARP main studs (instead of bolts) for years in these engines. And I have never had a problem. I am currently building a 406" FI small block for my street machine,'82Z. I am confident of at least 450lbs of torque @4500, and 450hp @5500. Now if that ain't enough for the street! I don't know what is. But it is important to note the I will not be using any NOS. Thanx,ANDYZ28

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82Z 305 w/comp 270 magnum cam,holly.TH700R4 w/B&M holeshot 2000 converter,& megashifter. 9bolt 3.27 w/1LE rear brakes 70mph@2200rpm ASE Master Tech plus L2
also recently obtained a
'69 chevelle SS396 w/Turbo 400,3.31 posi,11.0 to 1, headers,etc. Latest project car,'86 IROC stock 305TPI hit on left side not too bad

 

one trick that you might want to try is a set of 305 stock connecting rods with arp bolts. they are supposedly stronger and lighter than 350 rods and they would step you up to a 5.7 rod.