3400 Crankshaft

[SwiftDrift]

do you know whether or not the top of 3500 and 3400 rods are the same?

[caffeine]

They're different. 3500 rods are longer and have different specs altogether. Same with the 3500 crank.

[SwiftDrift]

you couldnt make custom rods that allow the use of a 3500 crank, or does the crank have different mains?

[caffeine]

Of course you could have custom rods made, but it seems like most people have SBC rods modified instead and then order custom pistons to match.

[SwiftDrift]

so the 3500 crank can be installed into a 3400, the main bearings are the same size? i thought the sbc rods were modded to work with the 3400, as it has the same size journals. oh well no need to complicate things, its not like i plan on running 600hp or anything. lol

[caffeine]

I'm not sure if the mains are a different size or not. SBC rods are also commonly modified to use with the 3400 crank. SBC rods are available in several different sizes though depending on the particular engine.

[SwiftDrift]

Someone should chime in who has had both engines apart and compared, i really want to know

[3400-95-Modified]

IIRC you can not put a 3500 crank in a 3400... it just doesn't fit.

I think modded SBC rods and forged pistons will be more than enough for a high HP build... When you blow a counter weight off the crank then I'd worry but I highly doubt you'll do that.

[Superdave]

You could always look... lol
3400- http://60degreev6.com/forum/local_li...catid=15&id=69
3500- http://60degreev6.com/forum/local_li...catid=15&id=70


But i'll save you the time, 3400 and 3500 (LX9) have the same main bearing size... however with the larger rod journals on the 3500 crank you'd need to do some serious clearancing on the 3400 block to make it work. There is a thread out there with pictures of the differences in the 3400 and 3500 blocks. Not worth it at all.


this thread should help you out quite a bit: http://60degreev6.com/forum/showthre...00+differences

[SwiftDrift]

I just want good balance and a good cam. And obviously a tune. Maybe some other small things but im not joining nascar or anything. I figured forged pistons and forged custom rods with the 3500 crank would be close with balance and be pretty damn rugged. I think the 3500 crank has a different stroke, i could have sworn ive seen somewhere that its doable, but i have seen that it isnt.

[caffeine]

3500 has the same stroke except for the destroked one based off the 3900 07+.

[SwiftDrift]

oh yeah

[Guest]

You're worrying about this far, far too much.

Many of us have built powerful 660s without using any additional balancing than what GM did when the engines were first machined, without issue.

The stock crank is neutrally balanced (after 1987), each piston will be close in each engine, at least good enough for 99% of people out there (including you), same goes for the rods.

Unless you're building an all out effort precision engine that must rev to over 9000, and do so for days at a time, additional balancing will be a waste of time/money. I'm not saying that it's not a good idea, just that it's not worth the effort for most engines, when near stock specs are being used.

[caffeine]

Agreed. Don't touch the bottom end until over 400whp IMO or over 7000 rpm.

[SwiftDrift]

so for drifting it will be fine? i need it to last a long time, and handle being rallied hard. i may replace it with something else down the road, but it would go into a daily driver after that.