451 Stroker questions

[451Coronet]

Hey all, new member here need some quick info.
Recently just assembled a 400 for my '69 Coronet so I can be cruisin it while I rebuild the 440. I also have a 413 shortblock stuck in the corner of the garage and discovered it had a steel crank.....liiight bulb

So here's my question(s), Question the 1st: I'm wanting to have the 413 crank turned down however the stock 400 crank was turned .030" on the mains, would it be ok to turn the 413 down to Standard B engine size, then an additional .030" to match up with my new bearings??

2nd Question: I know cast and forged cranks have different dampeners, can I use the 413 dampener and be done with it, swap the dampener and flex plate, or should I used the entire rotating assembly from the 413??

Some basic info, car is 727 auto, not sure if 413 was from man or auto car, 413 crank also has 6 bolt flex plate. If any more info is needed please ask. I'm looking to do this ASAP as I just rebuilt the front end and am ready to drive it!!!

 

[69Bee]

Answers:

Q1) I would return the 0.030" OS mains, and get STD Mains. Why cut more metal off than you have to.

Q2) Use the 413 balancer as it is for the internally balanced steel crank. You can knock the weights off of the externally balanced torque converter, or just get a new internally balanced one with the stall you want. The rods will be the same LY ones, so it will be fine to use either set. If you want to go manual, just make sure the crank is drilled for a pilot bushing.

Hope this helps.

 

[72 Charger SE]

Q1) I would return the 0.030" OS mains, and get STD Mains. Why cut more metal off than you have to.

X2 - bearings are cheap, don't turn the crank down any more than necessary

 

[Supershafts]

USE the 400 rods, the entire IDEA for the 440/413 in the 400 was to use the shorter rod to increase the RR and move the piston faster from top dead and increase cylinder filling....

Using the 413 or 440 internals does the OPPOSITE. . .

You lose performance advantages, and simply built a 440 or 413 in lighter shorter block.

Don't turn the mains down beyond what you need

 

[Cazbah362]

451 - 69Bee is right on

 

[rgp266]

The issue with the 3.750 crank and RB lrngth rods in a 400, or any B engine, is it will leave the oil ring groove far enough down the piston to actually protrude in to the Pin Bore and need a support rail under the Oil ring pack. Using the short B length rods cures that plus gives a deep skirt to the piston which increases stability. This will give a less-than-ideal rod to stroke ratio. Best solution, read most expensive, is to use Big Block Chevy length rods (6.535") and pistons from, for example, 440 Source or a simular supplier. And do not cut that 413 crank any smaller then the stock 400 Main bearing size. No sense in cutting more then needed and you leave your self room fo a rebuild or two.
Bob

 

[451Coronet]

Sweet, thanks all for the info. Gonna haul that crank up to the machine shop sometime this week, and order new bearings for it when it's done there. Thanks again.

 

[69Bee]

I thought you might like to read an old article on stroking... (motors you perverts)

 

[Hemirunner]

I love some of the responses on here.... open the block up for the RB mains, the bearing selection is much better. There's next to nothing for B main bearing choices, especially in a performance bearing. Running the low deck rod gives you no advantages whatsoever... the longer rod makes for a lighter piston which is less stress on everything. Oil ring support rails are no problem at all even in street engines. Using the longer rod also keeps the piston up in the bores rather than having the skirt hang out the bottom of the bore which lets you run a longer skirt if you wish. You'll have to cut the counterweights on that crank to get it in the block and if you use heavy parts, you may need some heavy metal to balance it.

 

[69Bee]

I love some of the responses on here.... open the block up for the RB mains, the bearing selection is much better. There's next to nothing for B main bearing choices, especially in a performance bearing. Running the low deck rod gives you no advantages whatsoever... the longer rod makes for a lighter piston which is less stress on everything. Oil ring support rails are no problem at all even in street engines. Using the longer rod also keeps the piston up in the bores rather than having the skirt hang out the bottom of the bore which lets you run a longer skirt if you wish. You'll have to cut the counterweights on that crank to get it in the block and if you use heavy parts, you may need some heavy metal to balance it.

If this was done, you would also need to have the #3 main thrust surface made larger to accomodate the new bearing. Make sure the shop can/will do this also. If you are going to run less than 600HP, there is no real need to go to the larger 2.75" mains other than ego. The cut down steel crank will suffice, and there are still a good amount of HP bearings available. Also, if you refer to page four in my post on stroking 101, there are 3 combonations using the longer 440 LY rod.

 

[Supershafts]

I love some of the responses on here.... open the block up for the RB mains, the bearing selection is much better. There's next to nothing for B main bearing choices, especially in a performance bearing. Running the low deck rod gives you no advantages whatsoever... the longer rod makes for a lighter piston which is less stress on everything. Oil ring support rails are no problem at all even in street engines. Using the longer rod also keeps the piston up in the bores rather than having the skirt hang out the bottom of the bore which lets you run a longer skirt if you wish. You'll have to cut the counterweights on that crank to get it in the block and if you use heavy parts, you may need some heavy metal to balance it.

Open up the b block to the RB mains so you increase drag by larger bearing surface area and increase drag by increasing speed ????

The shorter rod makes more power, the shorter rod is lighter.

The shorter rod increases the piston speed and increases cylinder filling at low and mid and high rpm...
The reason why you can take huge advantage of a big cam and heads and intake and not suffer any low end losses.


The end of the day all you did was build a 440 in a short block.... you created no additional power you simply spent more money by making the same mistake most all do....
So you were better off just saving the money and on the machine work and putting a really light piston in a 440..

There are tons of OOOOLLLLDD school thinking here, the more bearing area the more loss, it is easier to get performance bearings in smaller diameter than larger since performance motors use smaller diameters , TRUCKS use larger. . .

Ever been inside a good performance motor, the bearing diameters are not anything you see at these dimensions and the rod ratios aren't huge.

. Are you building a truck motor or performance motor. . . .

 

[451Coronet]

Thanks for all the feedback everyone.....bit more to all this than I previously thought lol. Already took the crank out to have it cut down, will pick it up next week. The 400 will primarily be street, very mild strip use.....maybe a burnout contest at the Nats this year This engine is just something low buck to throw in it so I can drive it and work some of the other bugs out...........so far I have a grand total of about $340 in this 400 haha (Including the cost of cutting the crank and new bearings) And it came with another 727 I might throw in the car just to see if its any good.
In the meantime I have a 440 I'm gonna build right, I broke a few rings and bent two pushrods so figured it was a good time to do a good rebuild since I had to pull it apart to replace the rings anyways. Plans are for 440source's 500" stroker kit with their 'Stealth' heads, maybe some port work by the local shop if I have the extra $$$