I do not think you can use the 4.0 pistons with the 4.6 crank and rods. Usually when an engine is stroked, the position of the pin in the piston is different. hence the 4.0 pistons would actually push too far out the block when at tdc.

 

Raises compression but does not go too far. Works fine

 

Hey lol, works great in my rig, sits flush with the block just like the 4.6 pistons minus the dishing. I have double valve springs to prevent any valves hitting at high rpm, even tho i rarely break 5000rpm.

I run 93 octane gas, 21 gal in tank, and 2 gallons of 110 to prevent knock. Engine runs good, has a lot of power from 3-5k with a bit of dead spot below 2 (probably caused by the cam).

I also have flowed heads, which may be less efficient at low rpm.

 

Hey man, just got done with this build after many months. I've been driving my other DD (WS6 ftw ) and kind of forgot about it after I needed a couple extra gaskets.

She's not loose yet! about 50 miles on it since! So far, runs great with a TON of low lope. I have no exhausts on it, lmfao. Its just open headers, which made for a rather nasty sounding 50 miles and tons of fun.

I've opened it up a couple of times, and boy does she sing. I know I probably shouldn't, but man I can't resist. Tons of power honestly, doesn't feel slow AT ALL. I'm running 93/110 mix but yeah no pinging/knock to speak of. I may try 93 and see how that's like.

Ill be sure to upload some videos, as well as some accelerations and maybe a dyno!!

Thanks for sticking with me, I haven't posted here in a while lol

 

Should have thought that one thru, rods are probably shorter on the 4.6. I remember stroking a small block chevy and used the hp rods i had, and had to purchase pistons that had pins in different place to keep from hitting the heads.
senior moment.

 

I've done a similar build, converting my 2000 Disco II with a 4.0 to 4.6. I used a 4.6 crank and connecting rods, but 4.0 pistons. I also used an advanced timing cam, the 53230 from Crower. I also used their cam-saver lifters. I have magna flow cats and muffler, removed resonator, and a snorkel air intake. I haven't ported or polished the heads, and probably won't. I did have the heads knocked down by about .015, and the block was honed, decked, and cylinders pinned. I had the 4.6 crank trued and the connecting rods trued, as well. They rods were almost all ok. 3 needed to be brought back into round by about .0002. The rebuild was easy, and I never had issues with the pistons coming up too high, either.

It sounds amazing, though, and has some crazy power differences. I don't use any specific fuel formulation, and I've never hit any knocking issues. My rig has been up and running for about 900 miles since the rebuild. I changed the oil about a month ago and found very little particulate matter, and the magnetic drain bolt had some metallic sludge, but not enough to be worried about. I am considering doing a custom power-chip job by a few places that will remap the ECU, but even without, it has some amazing pick-up-and-go. I'll consider remapping more later. Right now, I am working on the steering and electrical mods.

Hope that helps for comparison, and I hope it all turned out well.

 

ok so where are you guys at that did the conversion with 4.6 rods and 4.0 pistons in gems?

what octane gas?

did you change the cam to 4.6?