Originally Posted by hot_XD_falcon
Hey guys, just wondering if anyone has heard of or has experiance with using an EL-EF crank with 3.9L or 4.0L rods and pistons fom an EA-EB falc in a 250 crossflow..?
I have heard that the EF crank and EB pistons and rods are stronger than the stock 250 parts, but what mods are required to use them to make a stronger 250 donk....
Also I think ive heard of this combination being used in turbo applications for the extra strength..? Any truth to this..?
Any advice would be great
You will need an 84DA block or later from a late XE or XF due to the type of rear main seal used.
Use an EF crank as they have 12 counterweights, compared to the 9 weighted cranks from the late x-flows.
Get a set of 200ci rods from a 3.3 XE, these are longer than the 4.1 rods
A set of pistons to suit the longer rods, you can order ACL brand through Repco or Bursons.
Just make sure you get it all balanced properly and you shouldn't have a problem with revving to 6500 reliably.
As for strength, I have personally seen this simple combination used for 250 rwkw and 7000 rpm so for your streeter it should be up to the task I'd say.