erictheviking

Hi,
I've got a 400ci block with a 4" stroke crank and 6" rods.Can these rods be substituted for 5.7" rods without any problems.I know this sounds bizarre but I could do with knowing.
Many thanks.

RB83L69

Depends on the crank and rods.

Part #s would help.

You'd have to change pistons for sure.

erictheviking

Well it goes like this.I got the crank an Eagle part no. 440040006000.The rods are Eagle 6" rods.Basically I scored some JE pistons very cheap.They are for 4" stroke crank and 5.7 rods.I was thinking I would just have to change the rods and sell the 6" ones to a mate.I then saw an Ebay ad for the same crank and it said for 6" rods only!I don't want to get another crank but I could do with some ideas.BTW the 5.7" rods can be from any manufacturer.

RB83L69

The reason the rods matter, is because the crank's balancing is different.

The reason that crank requires 6" rods, is because the counterweights on it won't fit under the pistons when the pistons come to BDC, with rods that are any shorter.

So, with that particular crank, I don't think you can change to the shorter rods.

You can call or write Eagle; they're in the 662 area code, I don't recall which town, it's either Southaven or Horn Lake, it's been a while since I drove by there. If you call, see if a guy named Brian is there, and remembers a silver 83 Z28 with a 400 on the chassis dyno. I don't know their web address, what I thought it was seems to have vanished again.

erictheviking

I understand,so possibly a crank from a different manufacturer may work,I'll just have to do some homework.BTW the Eagle crank is internally balanced unlike a standard 400 crank,is this the main problem your highlighting?

Stekman

Why don't you just get the correct pistons and call it a day? I don't see the logic in replacing the rods and the crank, just to use a set of pistons, JE or otherwise. Just doesn't make sense to me.

erictheviking

I'm afraid the "correct pistons" for my application are going to be custom items.Considering where I live these pistons are going to cost me the equivelant of $1600.I can shift the crank and rods and get most of my money back,can you see where I'm coming from now?

RB83L69

The problem I am highlighting, is the one that requires that the stock 400 be externally balanced in the first place. There isn't enough space under the pistons at BDC to fit a large enough counterweight to do the job.