Procharging an lm7, need advice


Dat Rust Bucket
Dec 18, 2015
West Michigan
In the end, I've decided to keep my truck and start gathering parts to procharge next year. My intentions are to have a reliable daily driver running on pump gas that can really get down when I want it to at the strip one weekend and go to the sand dunes the next. I want to stay as economical as possible, while maintaining that I need reliability, so everything needs to be done right. Will be intercooled running between 5-12psi

So far in my searches I will need arp headstuds, gaskets, possibly a girdle kit and rod bolts. I've read elsewhere you can safely put 5-10 psi through it with supporting mods without a problem. When all is said an done I will have it dyno tuned. I will also be in toutch with Black Bear Performance.

I have also looked in to an ls6 cam swap and 799 heads.

I will be picking up a level 2 4l80e from Monster Transmission, and running a 3000-3200 stall converter. Most likely salvaging a transfercase out of a 2500HD. Everyone has told me to go with Yukon 4.10s front and rear..I've also been looking at Detroit tru trac lockers.

Here's where it gets tricky.

I've been told several things.
1. You have to upgrade the injectors and fuel pump
2. You don't have to upgrade either
3. Flex fuel injection from an L59 is the best route as the injector flow is higher.
4. 6.0 lq4 or lq9 injectors

So, does anybody have any advice on what my options are as far as injectors go? Also, what about valve springs, push rods and lifters? Omtake suggestions? Any spots I'm missing? This will be a 6000 rpm motor when all is said and done

Thanks all
Factory injectors probably aren't going to get it done for you. Is your truck returnless or return style fuel? If it's returnless as far as fuel goes you can pretty much just do a 340lph in tank pump, harness, siemens deka 60lb injectors and you'll be set for more power than the sbe can handle. I assume your truck is an 03 which means it has the weaker rods in it which don't sustain the miracle internet numbers you see put out as well as later motors. Keep stock intake, no point in changing. Heads can help but its just as easy to run more boost to make more power imo. If you're going through the trouble of camming it might as well put a good one in there, check out brian tooley racing/ljms motorsports( they are the same) or tick performance...they have a nice array of blower cams.

As far as the bottom end goes...rod bolts don't do anything for you, idk about the girdle shit but unless you're going for a aftermarket rod/piston rebuild most ppl will just tell you keep the factory gm magic in tact lol
Would it be possible to use rods from a newer generation lm7 or even the l33? I appreciate the info guys, I've done a few mild ls builds before but nothing over 400hp, so forced induction is all new to me. I'm excited to get this project started.

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I believe so, you see them for sale in sets on ebay every now and then or you could post on the sloppy mechanics page on fb and find a set pretty easy. Here's a visual representation of why the later rods vs early rods

Honestly, I think you're over thinking it.

Procharger, injectors, fuel pump, efans, long tubes and a good tune will be reliable and make good power. I wouldn't worry about anything else until you have a problem or build a motor.
The stock injectors absolutely will not cut it. I have an extra set of GM #46 flexfuel injectors I'd let go for $200 if you need some.

You will at minimum need the 340lph fuel pump but honestly, I'd do the Walbro 450 and do some research to see if E85 is available in your area. With a good tune and boost it can gain you between 50-100hp.

Pushrods are a must as well and length will be determined by headgasket thickness, cam, and if the heads or deck have been milled.

Lifters either true GM LS7 or Johnson 2110. Not an area I would personally save money on because if you need to change one, the head(s) have to come off and you'd likely ruin your cam as well. GP Tuning can custom grind you a cam and supply the cam kit (springs, retainers, locators, stem seals, timing chain, pushrods) and you can have him send you the lifters and oil pump too if you decide to add that on which I would absolutely do as well. YouTube LT1Z cam if you want to hear a few of his. Matt is extremely knowledgable and has been instrumental in my build. Piecing parts from here and there together rarely results in efficiency and efficiency = reliable power. Having one smart mofo design the package with what you have is always the better option. Just my opinion though...
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Little off topic, but I have been researching supercharger builds and am curious if a 3000 stall and 4.10 gears is going to be too much for a blower engine. I thought they need something to pull against?
Custom grind, fuel pump, injectors, boost, done, blown trans, replace, done, pop rear end, upgrade, done done.

I might recommend against Monster tho. And instead recommend an RPM.
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Steer away from monster transmissions. A ls6 cam swaps a waste of time a lot of work for so much to be left on the table.

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Im running 80mm turbo just 7 lbs of boost putting down 666 rwhp, im sure i can break into the 700's, but i dont trust the 6l80e, and i honestly want to have a reliable vehicle.

If you want see any numbers past 500+ upgraded fuel pump, lph450 or w.e, upgraded fuel injectors for higher fuel delivery. My 60#s are outflowing my pump, so im probably gonna swap out for a new one soon. Not too sure how air metering is going to work for you either through speed density or maf. Personally, id go with aftermarket maf, PMAS, expensive but the best there is, itll keep reliability throughout different elevations. Stock MAF will peg out with that much boost.

As for gears 3.73s are good enough if you have them on already, imo paying to have a regear id honestly get regeared at a ratio where you notice your money spent. 4.56. If not 3.73s are fine. Im lifted, and i have no problem putting the power to the pavement.

Id start looking into a high flowing exhaust as well, everything re-done.
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