Engine replacement

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May 8, 2026 | 08:54 AM

ericg

Thread Starter

4wd Low

Joined: May 2009

Posts: 11

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Engine replacement

I'm looking at taking a 4.0 block and putting 4.6 heads and cam on it. Into my 03.
Does any one have a list of things that they changed out while doing this?
I've got the heads and motor.
so I'm planning on replacing.
Lifters
push rods
bearings
cam most likely will be a stock 4.6
timing chain and oil pump. I'll pull the front cover off my current 4.6 that has a 2 year old oil pump.
I'll probably do the sensors while I can get to them easy.
Possibly rings if needed

Am I missing anything?

May 8, 2026 | 09:41 AM

whowa004

Pro Wrench

Joined: May 2019

Posts: 1,968

Likes: 947

From: Denver, CO

if you're doing that you might as well upgrade the cam..add crucifix seals to be replaced while you have oil pan off already.

May 8, 2026 | 10:43 AM

ericg

Thread Starter

4wd Low

Joined: May 2009

Posts: 11

Likes: 0

All that will be done. Might as well try to get all the leaks taken care of while its out.

May 8, 2026 | 08:50 PM

Best4x4

Super Moderator

Joined: Apr 2015

Posts: 7,986

Likes: 2,497

From: Beaumont, TX

Heads on a LR V8 are nearly identical minus the following:

14 Bolt Heads
10 Bolt Heads
10 Bolts with SAI ports

There isn't a specific head for 3.9, 4.0, 4.2, or 4.6 engines.