SBC Eagle cast crank or stock cast crank?

[Kemper007]

I am about to go on with my next build and have came to the crossroads of deciding to use a brand new eagle cast crank , or the original cast crank for my 406. I mocked the engine up several years ago and everything was fine with the original cast crank. I do plan on making over 500hp.

[lun40119]

Why aren't you at least considering a 4340 crank???? Personally I would choose at forged piece at that power level. That said, you don't need to go out and buy a million dollar piece. There are a ton of "SELF PROCLAIMED INET GURUS" out there that will talk about this and that, not having a clue what they are talking about.

I have got an Eagle cast crank in my wife's 383, but it is nowhere near the power level you are wanting. Maybe around 300. Hope this helps.

[jerry clayton]

One reason to use a new Eagle cast crank vs the oem one would be to go to internal balance

For the stated performance level of over 500hp I would recommend the 4340 forged one

[lun40119]

Jerry, does Eagle make an internal 3.750 SBC crank. I wasn't sure if they did. My wifes cast is external. Of course she drives it like its a friggen diesel, I don't think the thing ever gets over 3200 rpm ;). But, she does get 20mpg with it, so I guess I can't pick on her too much.

[Kemper007]

I have had good luck with cast cranks in higher power levels, that doesnt bother me. I guess its because I run short distances (1/8th mile) and having a good tune on the engine. I just wonder which of the two would be a better choice?

[want-a-be]

One reason to use a new Eagle cast crank vs the oem one would be to go to internal balance

For the stated performance level of over 500hp I would recommend the 4340 forged one

X2 on this.

But I have build more then a few engines approaching and exceedingthe 500hp mark with very good luck using cast cranks. It's all in the balancing. But I would prefer the forged crank if given the choice.

Don

[CLAYTONRACING]

Yes they do. We just balanced a cast eagle 3.750 with the I beam and a mahle flat top, although you might run into problems with h beams and a heavy piston depending on bobweight. I'd step it up to a 4340 for longevity.

[Cipges]

No sleeves......yet The crank is just a "modified" oem cast crank, offset ground sbc journals for the 4.35" stroke and cut down counterweights to reduce weight.
Thanks,
PHILLYGOAT

[CNC BLOCKS]

I have never been a fan of cast cranks as we balanced for another shop it was a cast Scat or Eagle set up for a stroker 351 W block it was run on the street and after a week it broke the crank in the middle and ruined the block, rods, pistons and the balance job required 2 peices of heavy metal in each end.

The customer is going with a 4340 on the next build and hopefully it last more then a week LOL.

[Awesome Bill]

The crank will handle the power but for how long and for what a brand new 3.75" internally balanced crank cost, you would be silly for using the stock stuff. If just for the reason of external balance versus int, the internal is way easier on the crank flex stuff. I sell those new interanlly balanced units for $249.00. New would be better. You can get them anywhere and most likely cheaper. They balance up very nice.

[want-a-be]

The crank will handle the power but for how long and for what a brand new 3.75" internally balanced crank cost, you would be silly for using the stock stuff. If just for the reason of external balance versus int, the internal is way easier on the crank flex stuff. I sell those new interanlly balanced units for $249.00. New would be better. You can get them anywhere and most likely cheaper. They balance up very nice.

Again ,...I agree totally with this. I've got some circle track stuff out there in the lower classes using the cast cranks rods and pistons. Like Bill says though,..get a new one. You spend as much getting the stock one internally balanced as you will on a new one and it will be cheaper to get balanced.

Don