I know you guys can do it with ported heads and a big cam and headers, in an LS1 or any 6.0L, and make 422.5 rwhp corrected to sea level.
But for less than you'll pay for the LQ4 from LKQ, I can get an LKQ 5.3L to do it at 4500' elev., uncorrected.
First, the LQ4 cost me $800, while the LM7 cost me $500. I was bored, and went to www.turbonetics.com, then looked at compressor maps. I settled on the T70 as being the best for this engine at this elevation.
Then I went to www.ebaymotors.com, and searched T70. first the chinese junk for $168, then $175. several choices at that price. Then the better Chinese versions, at $259. There was a used Turbonetics T70 for $1500, but screw that.
Okay, by the time I add in a used intercooler from any source, it's no longer cheaper, but since it doesn't take an $800 pair of headers from Hawk's, I'm still ahead.
Okay, the intercooler will cost me about 1.2 psi, so 2 bar out of the turbo is 1.92 bar into the 285-horse 5.3.
285 x 1.92=547.2 HP. Now, to correct that to 4500' elev is x0.8875. 547.2x0.8875=485.6 HP. Then to correct for a manual trans and a Ford 8.8" axle, both with synthetic lubes, is x0.87. 485.6x0.87=422.5 RWHP
Since you need bigger injectors for that power, whether you do it turbo or cam/heads/headers, you can't really include those in the price comparison.
Heck, this is cheaper than nitrous.

 

you'd get more than 422 to the wheels with that combo and it's been done many times

 

The math says I wouldn't, and I never claimed it was a new concept.

 

Of course i know you know it's not a new concept.

BTW, do you have heads for sale anymore? Looking for either ported cathedrals or some stock l92's or ls3's

 

That assumes that the process is 100% efficient and can produce exactly 92% more power over atmospheric conditions from the 1.92 bar pressure. Not necessarily the case. Really have to factor in how efficient the turbo and intercooler end up being to determine how hot the air charge gets, as that will effect the airflow thru the motor, and the final power output based on the tune. Its a good approximation tho and is a cheap way to do that power if you can fab up the system yourself. All depends on where you source your parts, it can end up being a very cheap but effective/powerful motor.

15psi on any LS based motor will make for some fun. My buddy had a 4.8L truck motor with 241 ls1 heads/big cam/ls2 intake and on just 9 psi it made 566whp thru a 14 bolt truck rear/T56 combo.. Ended up making over 700whp on something like 16 psi I think. Not exactly apples to oranges but 15 psi on a stock 5.3 is gonna get a car moving.

 

and LM7's can be had even cheaper than that too, there's an add on Ebay where a company is selling 5 of them for 1800 shipped, sell four of them @ 450 a piece, and the one costs you nothing.

 

I sold my 241s to Primetime91, I guess he was happy with what I did to his Dart Iron Eagle 200 heads. So, he's my first repeat customer from TGO. He got to meet JamieSweet.
Anyway, I have the LM7 heads sitting there with a different port job in each port, awaiting a trip to a flow bench to see if I can do better than TEA. If so, then the next step is getting my best shape into a CNC machine.
I know shipping is a big expense, but I can improve any heads sent to me, and I'm still offering the $100 price for stage 1 port and polish. And I can have them done within a week.

 

That requires having $1800.
Local pricing is $500+, but I did get a burned one from Pick-N-Pull on half price day for under $100. The intake manifold and could were junk, and some of that crud got past some of the intake valves.
Still, anyone in the 48 states can get one from LKQ for around $500, any day of the year. And that ain't bad.
I posted this because I decided it beats the heck out of trying to piece together a 350 horse 350, even in final cost, assuming starting with nothing both ways.

 

yeah you cant beat it. If you can do basic cutting and tack welding pipes together, you can build a turbo setup and do it on the cheap. Swap like this is perfect since you need some sort of header/manifold anyway, you can build one out of mild steel header tubes.

The only thing I am not sure on is wiring the ECM to stock guages since you would want to do this on the cheap. That could be difficult I'm not sure how everyone is doing their LSX swaps. Then you would need to tune it, which HPtuners and other programs to do so are in the 400-600 buck range. Dyno tunes would be about the same cost.

 

Hell, i am going to try to use a H1E holset for my first turbo build in my 86 TA, but i will be looking for a S480 for the future turbo to really get things nasty. Still will be carbed and wont need an intercooler