Anyone have any idea where to get a 4" stroke forged crank for a 1 Pc Rear main seal engine?

I asked K1 and they need $750 and 12 weeks lead time. I'm curious to know if anyone has seen a 4" Stroke forged crank anywhere else for a reasonable price?

 

$750 is pretty cheap..

 

I understand that especially for a custom crank, but I was just curious if anyone knew of a current production version....

 

I purchased an eagle 4 inch stroke for my car and it was a production piece for 1 piece and 2 piece rear mains. I can get you part numbers if you need off of my box tomorrow, let me know! I have some pics posted now in a tread i have started showing my build up however still collecting parts

 

What are you building with a 4 in stroke?

 

408ci. 4.030 bore, 4" stroke, 5.85 rod, and a piston for a 331 ford motor........

And I'm not to keen with the fact that Eagle has had so many failures recently.....Kinda worries me....

 

DO NOT DO EAGLE!

Lunati has a 4" crank, not sure if they have one in stock but you could call them. Pretty spend thought I believe.

 

Ahhh..that's the secret..

 

I think eagle is pretty good. There are a lot of high hp cars with eagle products

 

It depends on what day of the week it is. The failures have been more noted with their cast cranks. I haven't really ever read of a forged crank of theirs breaking. The problem comes with their QC. Lots and lots of stories on how even though the assy. came pre-balanced the machine shop noticed it was not. There are those who had to add metal. The real big problem with their cranks is their specs between the crank snout being too small and the flywheel/flexlplate centering ring and pilot hole being too large. I have one and had to have my flywheel machined to fit as well as as requesting Eagle send me an oversized bushing. So yes, if you don't mind those kind of hiccups with Eagle then no worries...

 

The big thing is the 5.85 rod. You actually have to grind the counterweights of the crank down to allow the 5.85 rod, as most require the use of a 6" rod. The piston is what allows a little more compression height that will allow for a more streetable combo. A compression height under 1" is considered "race only". The main reason is it leads to the piston rocking in the bore, commonly known as piston slap. By getting the piston for the 331 ford, it has a comp. height of 1.175 which has been proven to be a reliable street height. It also allows for you to spray a healthy shot at it and not have to worry about destroying the piston. The biggest issue with the 4" stroke is the fact that you have to clearance the block for the rods considerably. This leads to the possibility of hitting the water jacket down by the pan rail. To solve that you short fill the block. Now according to leading block manufacturers like Dart, you will then have cooling issues on a street car. Now I have witnessed these motors doing ok on the street as long as you keep an eye on the oil temp. I figure will a factory oil cooler, maybe plumbed to a larger cooler if needed I won't have any issues. I'm thinking this will be a great street motor. Put some large heads like the AFR 227's and a nice rowdy cam on a wider LSA and it'll be a fun driver that I can spray at the track. All while staying under the 7K RPM limit of the stock PCM.....

Should be a fun project

 

i have a brand new 4in eagle crank in the box if you want pm me ill make you a good deal. Their forged cranks are good but there cast ones have a little more issues

 

Yes it does..hopefully it works out well. That is alot of Stroke in a Gen I style Block, I say that in refrence to it in a LS Engine. It has been done though.

 

Sounds like a good project your undertaking there! Where you getting the pistons? Keep the buildup posted, GL.

-SS

 

Pistons are from Probe. They're actually forgings for a 331 Ford engine.

As for the build, this is going to be a very slow one. Hopefully should be getting the block here in a few days, then I won't be doing anything until after X-mas....Kids and Family take priority. And unfortunately the current engine has absolutely zero issues. So it will be a slow build but I will definately keep everyone up to date with the issues I have if any.

 

OK - I, like the Merv, am also interested.

Now Duh, just for your consideration, I too was looking at stroker crankshafts; and a number of "better" forged crank manufacturers make a 3.875" stroke which only results in a 395 displacement (at your stated 4.03" bore) vs. the 408, but this 1/8 inch reduction in stroke may help reduce the problems associated with: notching the block, filling the block, and adding an external HD oil cooler; to act as secondary method to cool the engine in total.

Regardless of stroke you ultimately choose, I must ask, how does a Ford 331 engine's piston properly 'mate' with a Chevy connecting rod?

[FYI - My background is with Pontiac engines anyway (421s, 400s, 455s), so my LT1 is my first non-Pontiac engine ever!]

But to be positive - Yes, I agree, displacement is GOOD, so if you can enlighten this arrow-head as to how to make this happen, then (as Ross Periot would say), "I'm all ears!"

 

Subscribing!

-SS

 

As for keeping the 3.85 crank.....I dare to be different. I don't mind the extra prep work associated with the large displacement, and I really don't want the same 'ole 396 build. Nothing beats pulling up to a mustang and when he asks "whatcha got in that thing?" and you can respond either "A small block" with a sh*t eating grin or "Twice as much as you do!"

I'm a little bit of a smart *ss. I've always been brought up there is no replacement for displacement. And since in this case I'm looking to build a mostly street motor I can get away with it.

The secret behind getting a "Ford" piston to work is getting one with the right pin size. Most rods sold for the SBC have a .927" wrist pin. Most Fords have a .912" wrist pin. The nice thing about probe is they make their ford pistons with an optional .927" pin. Essentially it turns it into a SBC piston by doing this. So instead of ordering a custom piston, I can just order one off the shelf. Makes life so much easier.

 

Interesting.

So Duh, forgive my ignorance, but I must assume this Ford Probe piston is either for a 4 cylinder or 6, as I don't believe I ever heard of any V-8 Probes, and I lived in Dearborn MI (a.k.a. - Home of the Ford Motor Company) for 14 years!

Wait a minute! On a third re-read, I saw the light: "Probe" is a piston manufacturer and NOT an automobile - Now I get to say it: "Duh"!

Alright, so if I also wanted to walk down a similar (but not as large) path and create a 395 / 396 LTX via a 4.03 bore and 3.875 stroke, would the special Probe manufactured Ford 331 pistons, crankshaft shaving, and the "in-between" 5.8 inch con rods still be required?

I might choose this set-up vs. the 383 / 388 if it can be done w/o too much trouble, as I've been enjoying my 11 lbs of boost (via my STS) on my stock LT1, but I'm sure one of these days it'll be time for another rebuild!

 

i would like to see some more people using a 4' stroke canks.sounds interesting