I need to know which rotating assembly components are cross compatible to lower the CR in my 3.4 for a turbocharged hybrid setup down the road. ie. which rods work with what pistons and cranks and such.

 

I assume you're talking about a 3x00 hybrid? Just use 3400 pistons with the 3.307" crank.

 

That would be the stock crank right? and what about connecting rods, stock rods too? And assuming thats the case, would a 3500 crank work as well, without modification, would like to swap to a forged crank in the process.

 

The 3.4 & 3.1 crank is 3.307" stroke, and you use the rods that come with the 3400 pistons since they're pressed in- consider rebalancing .

The 3500 rod dowels are 2.2 inch. You either need to grind the dowels down or have rods modified. I'd go with fatter sbc rods machined to fit since you're looking for a stout bottom end anyway.

 

Define pressed in? Figured all rods connected to the pistons the same way and were removable, but from the sound of what you're saying sounds like the 3400 rods can't be removed from the pistons? In which case I would have to get new aftermarket pistons to use the 3500 crank.

 

Interference fit. Has to be heated and pressed out with a special jig. Custom forgings are pretty much a given with the 3500 crank in anything but a 3500.

 

Well heres a question, if I buy aftermarket forged pistons for a 3400(Idk of any companies that make forged for a 3.4 rwd, let alone in that dish size) would they have the same style conrod fitting?

 

The pins are pressed into the rods. Most will probably be oe style.

 

I'm having the rod pins on my 3500 crank ground to 2.00" and will be using the stock 3.4L V6 rods since they're forged from the factory. Finding SBC rods with a 2.20" rod-pin diameter is harder than you might think. You should still be able to use the 3400 pistons since the stroke is very similar between the 3.4L and the 3400...

 

the 3.4 uses the same exact crank as the 3400 (981 casting), also the same rods as all the rest up till the 3500 which changed to powdered metal, 5.9" long with a 2.25" big end.

Look into small journal 327 rods, they need to be machined slightly to fit the 60v6 crank and bearings but you can find some good aftermarket versions.


If you order the forged pistons from wot-tech i'm pretty sure you can get them sized for either the stock rods or the SBC rods.

 

Hypereutectic pistons for the 3400 are also available from Summit Racing at about $25 ea;might be sutiable for low boost.