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Thank you both for you interest and input. Please understand just because I don't always take advice does not mean I don't consider it and see how it fits for me, A little back ground may help. I bought this 03, extended cab, SXT with a 3.9 V6 and five speed. Having never owned a V 8 or automatic for my personal use, it with timeless styling four wheel disc, big wheels and tires had to give it a shot. It was not hard to spend a couple thousand on brakes, suspension, AC, alternator and drive belt parts. At that point I could not stand the sound a std V6 makes. It sounds like it is sucking, so on went the complete single 3 inch exhaust system. My exhaust guy is third generation and does the NASCAR exhaust school every few years it is made of the correct parts. For a whole year it was great and ran fine. It did not begin to show issues till I started making long high speed trips pulling 2000 lbs. The first one went fine no codes no issues. I had learned a few things about the ride. Just a wild guess but I feel it's at least 20 HP short of what I need. Just running up and down 95 even small hills are an issue in O/D 5th. Having never heard a V6 in lugging distress it scared the crap out of me. I though the engine was coming apart. OK, no towing in 5 th gear. Even in 4 th it's a little short of power. Many have suggested more rear gear which would move things up the RPM scale. With something in the 175,000 miles on the OD the engine could use a freshening up. The cost of a std rebuild using stock parts with no effort to improve is big money. So I'm spending a few more dollars looking for something that may not be there. We have a local shop that holds an open Dyno day a couple of times a year. Once done I may give it a go. As for the Keg issue I believe there is something to be had there. If not HP it may be something that supports other power adders. Again, thanks and I'm about ready to start. If I had someone to text pictures to that would post them to a thread as I add text it could be interesting to some. Steve
I feel you would only improve performance. Better valve events with the cam. More compression. Better breathing in and out.
You have no choice but to see some nice gains in my opinion.
 

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Discussion Starter · #82 ·
As I turn the corner on this build parts are arriving every day. I have parts at several machine shops One does my block and cyl. head work, one does custom piston and connecting rod work, and the last does V6 balance work. If we decide the crank needs grinding we will use another machine shop. Having managed a auto machine shop for 25 years I know you not only need the equipment but the talent to operate it. Reading back though this thread there is a lot more info and advice than first appears. Some of it comes from experience, some from reading some from mistakes made.

It was recently mentioned that I must have some other motivation for my failure to take good advice. That got me to thinking about the whole process. Going though the board there are two things you can depend on. One is the question "How to get more power from a 3.9 V6" seems to come up often. The second would be the common answer " Why not put a V8 in it?" seems to follow. I have been rebuilding engines and trannys for the last 59 years.

For anyone interested, I have a heavy truck with a under powered engine. My sore back will attest to everything about this V6 engine is heavy. So I have a big heavy lazy V6 engine. Being rated at 175 to 195 HP that's not even 1 HP per cubic inch. The V8 options are even heavier and lazier. Even with the V6 there is so much weight on the front end I believe the suspension needs reinforcement. My aim is to bring the V6 up to 1 HP per cubic inch. If this works having V8 power without the weight of two extra cyls I win. It has also been mentioned that I could spend a lot of money. Yes, I have and I have stopped counting, as it does not matter. None of us are driving 20 year old trucks because we can write a check for a new fully loaded Big Horn $84,000. Even the base at $53,000 is a little out of my range. Insurance and taxes if the payment don't kill you. The plan was to complete this project at $10,000. That shound have done the suspension and brakes complete. Engine and tranny rebuild, Paint job, AC service with all new parts and full interior redo. I'm going to miss my mark mostly due to the engine over runs. I'm still looking for someone who would allow me to text them photos and then post them to the 3.9 V6 engine build thread. Just got a text my headers are ready for pick up. I'd like to be able to share pics of that. I'm doing the work, spending the money and trying to figure it all out. Someone else can post the pictures if they like or we have none. Steve
 

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As I turn the corner on this build parts are arriving every day. I have parts at several machine shops One does my block and cyl. head work, one does custom piston and connecting rod work, and the last does V6 balance work. If we decide the crank needs grinding we will use another machine shop. Having managed a auto machine shop for 25 years I know you not only need the equipment but the talent to operate it. Reading back though this thread there is a lot more info and advice than first appears. Some of it comes from experience, some from reading some from mistakes made.

It was recently mentioned that I must have some other motivation for my failure to take good advice. That got me to thinking about the whole process. Going though the board there are two things you can depend on. One is the question "How to get more power from a 3.9 V6" seems to come up often. The second would be the common answer " Why not put a V8 in it?" seems to follow. I have been rebuilding engines and trannys for the last 59 years.

For anyone interested, I have a heavy truck with a under powered engine. My sore back will attest to everything about this V6 engine is heavy. So I have a big heavy lazy V6 engine. Being rated at 175 to 195 HP that's not even 1 HP per cubic inch. The V8 options are even heavier and lazier. Even with the V6 there is so much weight on the front end I believe the suspension needs reinforcement. My aim is to bring the V6 up to 1 HP per cubic inch. If this works having V8 power without the weight of two extra cyls I win. It has also been mentioned that I could spend a lot of money. Yes, I have and I have stopped counting, as it does not matter. None of us are driving 20 year old trucks because we can write a check for a new fully loaded Big Horn $84,000. Even the base at $53,000 is a little out of my range. Insurance and taxes if the payment don't kill you. The plan was to complete this project at $10,000. That shound have done the suspension and brakes complete. Engine and tranny rebuild, Paint job, AC service with all new parts and full interior redo. I'm going to miss my mark mostly due to the engine over runs. I'm still looking for someone who would allow me to text them photos and then post them to the 3.9 V6 engine build thread. Just got a text my headers are ready for pick up. I'd like to be able to share pics of that. I'm doing the work, spending the money and trying to figure it all out. Someone else can post the pictures if they like or we have none. Steve
Well Coop,
You travel on uncharted ground.
I am wondering if you'd hav better luck looking up any drag history of someone running a stock class with the 3.9 in anything.
That would at least give you a clue as to what gains could be made.
Personally, I think you will achieve your goal and this combo being as or more powerful than the 5.2
 

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Discussion Starter · #84 ·
Well I now know the answer to my own question. It's highly unlikely anyone has gone as far with a 3.9 as possible within the ability of the PCM to deal with it. Just like anything I get into I have studied everything I can find on the subject. Talking with suppliers rather than just looking at a web site helps. I was told parts would be an issue. Had to buy 5.2 parts in sets of 8 but they are parts that can be made to work. I was told it was going to be expensive. By Wednesday next week with a little help from USPS and FedEx ground I will have received $4150. in parts. And I'm still waiting for back ordered springs caps and keepers. None of the machine work has been billed yet. Looks like my $4000. projection missed. There is nothing in or hanging on this engine that won't be new/improved or correctly rebuilt. I'd still like to start a new thread and post pictures and text. I need a volunteer to receive pictures via text and post them in order. Two or three a day should build interest. Steve
 

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I wouldn't count on that.
Even the 5.9 small block has a more and more limited following and the 3.9 next to nothing.. Everything Mopar is being usurped by the hemi.
Your project, to put it kindly, is about 18 years too late to begin to garner interest,
Mopar runs in my veins so I'd be like that hen's tooth you found.
 

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Discussion Starter · #86 ·
Well, thanks for letting me know no one cares. I guess I have been having so much fun with this build I didn't notice. What good is knowledge if you don't use or share it? It doesn't matter maybe some of what I share will help someone else. I will say after buying what may have been a 100,000 mile 3.9 V6 core I have a much better grasp of what issues I'm dealing with. If I were Joe Shit the rag man with three curtain climbing crumb snatches and at home wife. The core engine would have gotten a hone, clean, cam bearings and freeze plugs. Crank polished, valve job, timing chain, rings, bearings, oil pump and gaskets.
I expect that with the engine in the truck and the cast off parts from the core I'll do a common rebuild on that one. Thanks for your input. Steve
 

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Discussion Starter · #87 ·
In spite of the very strange year and the fact that many suppliers are either back ordering or drop shipping and some things are just not available. According to the tracking numbers if Monday were not a holiday the last of my rebuild parts would arrive. Met with the guy grinding my crank, the guy boring the block and met the guy who will do balance and head work. That makes four auto machine shops involved in my build. For those who like Keg mods I completed those yesterday. Once the balance of parts arrive and all machine work is at the machine shops with a due date I'll start a new thread. Steve
 

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Discussion Starter · #88 ·
A side note, I mentioned I ordered 5.2 aftermarket pistons in +.020 O/S. Part of my motivation was the ring set carries a thicker, deeper higher tension oil control ring. I have no idea what effect this will have on MPG but if it stops oil burning for a very long time I'll deal with it. Having built Hi Po engines before I looked for a set of .025 O/S rings to allow file fit of ring gap. Well they have them in .035, .045, and .065 but no .025. To make matters even worse I was unable to locate either of the three part numbers listed. One set has Moly top one cast top and one chrome rather than SS oil. I checked and it seems one set will be produced by 4 June as a cast top not for me. Another may be shipping by mid June and the one I wanted late July. None of that works for me. After working my way though every ring set offered by Sealed Power I located a set for an engine with a 3.905 bore and a .030 set would be the .025 file fit set I wanted to start with. Give me Lemons and I'll make lemonade. Steve
 

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Discussion Starter · #89 ·
You Know Ralph has posted concerns about the ability of the NV3500 handling the increased HP of a V8. No promises but I'd like to think my 3.9 V6 will at least match a stock 5.2. Considering I'm currently really deep into this truck I considered a rebuilt NV3500 as none new seem available. After checking junk yards they are all gone to rebuilders. The price of a rebuild without a core ( I'd like to play with my core ) is about the price of a TREMEC 5 spd rated at 500 lb ft and 7200 RPM shifts. The complete kit cost $4885. And they say there is nothing available for the 3.9 V6. Get your check book out. Steve
 
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