Is it possible to rebuild a 4.1 to a 4.6?


it's all good
Franklin In
to tell you the truth I'm not sure. So don't hold me to what i am going to say. I am not sure if their is enough metal on the block to bore it to fit the piston sleeve. that would be my consern. also i don't know if the ports will line up between the two in the block. These are all things that i would check before i spent the money and all the hard work. hope this is helpful like i said i don't know any of this for sure.


Well since I asked this question, I realized that I have a 3.5 and not a 4.1 which kind of blew the idea out of the water. I am suprised this question hasn't been asked before. The reason I originally asked was that I would think that they would manufacture one size block for a range of engines and would fit the piston and sleeve to it to cut down on costs.


Well-Known Member
You would have to see the two sleeves together. Side by side. Not to mention the crank. Now lets say you need to bore out the block. First its Cast aluminum. Not a sutible material for machining Unless your a machinist. But lets say you have a milling machine. Are you willing to drive a boreing tool down the block? if it even grabs the side wall a tad off center its over... So what I'm really saying is NO. IMO stay with porting and policshing your stock version. if you want a 4.6 go buy one..It will be cheaper in the long run.


New Member
FIRST POST HERE. Yes I know it’s an old post but I have just brought a savage with 3 spare engines. The 4.1 internals fit straight into a 4.6 no modifications needed. I’m sure hpi are just like car and motorbike engine manufacturers and design one block then sleeve them to size.

P.s the 4.1 internals in the 4.6 fired up in less than a second on the roto start first time