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Chris's 2003 6.4 Hemi Stroker Build

140K views 2K replies 28 participants last post by  HemiLonestar 
#1 ·
Well I had a thread about doing a cam swap, now that is over, time to re-start all over again and do it right! I do it nice, cause I do it twice! :rofl:

I had really wanted to do a stroker kit the first time around, but time and financial constraints weren't allowing me to. But after I found out the fresh rebuild was burning major amounts of oil in cylinder 1, I decided to just go for it. To start the process, I chose to get a used 5.7 block and build the stroker first. When its all completed with the necessary machining and installation, I'll pull my old engine out and swap over the heads and accessories. I've already added a Comp 260, new valve train, torque converter, oil pump and timing set the first time around, so I have a good base to start with. So after a bit of searching, I found a blown engine at a local junkyard for $400. They didn't have any info on why it was blown or the mileage, but I figured I would be only using the bare block and it would be over-bored to begin with so it couldn't be too bad. Any other usable parts would be experimented with or sold to help recoup the cost. After pulling the heads I found the reason it was blown, cylinder 6 had no piston head left, it was completely blown out with just the rod and wrist pin left. So I will have to have one piston re-sleeved, I don't think that is a big deal in the end. Other then that, all the other cylinders are at standard bore size and should clean up well. At this point I have the engine stripped to the bare block, tomorrow I'll start with the wire brush to remove all the old paint and rust. Then it will be sent to my local performance shop to bore it out and get it re-sleeved.
I plan on using the SCAT Modern Muscle Stroker Kit from Summit Racing. It's in my price range and comes balanced. So feel free to pitch in any suggestions or tips!
 

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#2 ·
So just a few basic questions as I'm starting, will I need to upgrade the fueling system at all? Bigger injectors? Fuel pump? Any other things need upgraded a bit to keep up with the extra displacement? I'm going to see how long my stock trans will hold up, then deal with an upgrade or swap...
 
#3 ·
While in the machine shop I would have them replace the cam bearings.
 
#4 ·
I noticed in the service manual it claimed these were not serviceable by the "average home mechanic". Any idea what makes these bearings so special?
 
#5 ·
You will need the mandrels to drive each bearing into place with the rear bearing clocked specifically to the oil port. Most of these bearings I believe have a groove on the back shell and the exit hole is set to 5 o'clock. Double check this information to make sure it is correct for your application.
The 03 uses a 48psi fuel regulator. Not sure if you scaled your current injectors to compensate for this or not. 05 pcm used 58psi. I am not a fan of dead headed fuel delivery systems. I would remove the oem fuel regulator and use a external adjustable regulator with a a return line. Using the return line insures the fuel being provided to the injectors is relatively cool as it is fresh from being circulating. -6AN hose will support 750 hp and both -6 AN feed and return lines is suffient. Used 6.2 take off injectors are available from Modern Muscle which should be good for your build. I think they are something like 55 pound injectors. If they are too big, they can be scaled in your tune.
 
#6 ·
The pump should hold but if I were you I would drop a walbro 255 into the factory basket and be done with it run it like stock and don't worry about it. Get stage 1 srt injectors or 6.2/6.4 stock hemi injectors will give you room to grow. The return style setup is suggested not required for what you wanna do IMO. Also my engine has a sleeve in cylinder 2 and I am boosted high compression lol and doing fine. Main thing is you will tune to the sleeved hole as that one willrun hotter than any others due to metal differences.
 
#9 ·
Is the cylinder cracked? Have it magnafluxed, and sonic check . Check the webbing under the bore in main bearing area ,should be fine , small end of the rod is still there but strange things happen when a Piston disappears.
Cam bearings in these are not an easy install, it boils down to right tools for the job and a little bit of experience.
As for the Fuel system and tune......I'm just going to sit back and eat my pop corn and listen to the advice that's given.
 
#10 ·
When I took off the timing cover I discovered the timing tensioner was broken. I'm assuming that's what caused the piston to blow. That seems to be a common problem on these engines. When I pulled apart my other engine the tensioner broke in my hand with very little force, so I think it was only a matter of time before this happened to me.
I'll see what my machinist has to say about it first. Other then the cylinder chamber and the sleeve, nothing else is damaged. No webbing or anything down in the block is damaged, all the bearings still looked in good shape. The block hasn't been bored or rebuilt, and all the other cylinders looked in better shape then my old block. No score marks to speak of. So we shall see.
One of the other minor upgrades I want to do while I'm at it is clean up the intake manifold and make it look decently nice. I think I'll add in the Taylor shortie wires at least, I'm also interested in the 6.1 coil swap. I saw someone who grinded off all the extra plastic on the intake manifold to clean it up and paint it, turned out nice. Anyone know if all the plastic fins and ridges are from molding, for extra ridgidness, or for cooling purposes? I'll have to find the picture of his intake. I have the extra manifold that came off the engine, so I figured I could play around with it on the bench and see what I can do.
 
#12 ·
Spent a few hours with the dremel. This is gonna look sweet after it's finished
 

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#14 ·
The ribs on the back behind the TB, are in case of backfire..... personally I think they are over kill.
Looks good cleaned. Less truck and more HP looking.....if that makes sense
 
#15 ·
Yeah it was in the back of my mind on what was a bad idea about taking off, especially since the back isn't really seen when it's mounted in the truck. That's why I didn't remove the webbing on the base of the manifold. I figured that would have some structural benefit. I feel like cleaning it up is a better idea then the car manifold. Not losing any low end performance, but it still looks more like a real intake
 
#16 ·
Looks good...
 
#18 ·
For the time being I think so. The way the build is going I don't want to put up the extra $500 or so to get a good stroker cam. That can be a future mod, just swapping the cam out isn't a big deal. I saw truck trend or hotrod.com did an article with the 260 in a 6.1 stroker and it ran good. So it will be a trial and error kinda thing at this point. But who knows...
 
#19 ·
I called Comp today to check with them, they said it would still work fine in the stroker, it would still be a great torque cam and I shouldn't have any clearence issues. There's no doubt there is more to gain from a custom grind cam, but for the time being this will suffice.

So just a general question, kinda a thought on the back of my mind. What can I expect from the 392 stroker as far as driving experience? The way I imagine it, my guess is that it would feel very "torquey" around town. Are n/a 392's inherently faster going down the drag strip? Or more just a bottom end kinda design? One of our company work trucks is an older f-250 with the v-10, driving around town and going up on ramps I was surprised how much different the low end felt compared to my truck. I'm guessing that's what to expect
 
#20 ·
Should make for a good driving experience with increase torque across the board. I would expect your quarter mile time to improve by at least a half a second.
 
#21 ·
So I'm doing some thinking and reading. I'll have a decent chunk of money coming from a bunch of overtime. I was mainly using it for the stroker kit. The more I'm reading about the 46rh the more I'm sure this wll be installed in my truck in the future. Would it be better to install the stroker engine and see how long my 545 lasts, and deal with it then, or buy a trans and do that first. Decisions, decisions....
I found 2 46rh's in my area for $400-$500, claiming the were at least rebuilt recently. Not sure how hard these are to come by when I need one in a pinch.
 
#22 ·
Personal choice, I choose to replace the 545 before I hurt it. But I often prepare for mods ahead of time..
 
#24 ·
I would normally agree, other then I want to get the oil leak taken care of soon with the new engine. I already have the block ready to head to the machine shop. I did check car-part.com and there are tons of transmissions available around me, so I guess I don't have to worry about finding one. It's a tough decision...I guess I'll see how much money I have left over. I don't typically drive crazy, so I'm curious to see at what point my trans breaks haha
 
#25 ·
So have most people just blown the 545 from downshifts? Or do they also blow from a dig? My understanding it will last a good bit if you drive conservatively and start from a dig, which I'm ok with, I try not to street race anyone on the highway. Just more thoughts while I'm bored in class
 
#34 ·
Ok not to sound completely out of touch.....but what is DIG ?
 
#27 ·
Ok thanks for the input, I'll ride it till it dies. Maybe I'll buy a 46 and rebuild it, and leave it sit till mine stops running.
 
#28 ·
A 3spd floor shifter being used on a 545 is the same as for 46 trans.
 
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