shelby987

I have a build-up I am working on and to save time I would like to buy an assembled engine but the ls1 and ls2's seem to be a bit out of my price range for anything low mileage. I have come across several LM7 (5.3) engines with very low miles for $1,000. My question is this, what kind of performance improvements can I expect from installing LS6 heads, cam, intake, and a set of headers on a 5.3? (yes, I know these cost $$ too, but I think I can get all of the above for about $1,500 and have everything together for less than the cost of a high mileage ls1).
Basically I was wondering if anyone had any data on these mods, or at least advice as to whether all of these changes will still put the lm7 below the output of a stock ls1.
Also, are there going to be any issues with installing a T56 behind a 5.3? (aside from needing a stand alone/reproramed ECU)
Thanks!

pwrtrip75

iTrader: (8)

Only thing about putting LS6 heads on it is it would lower the compression ratio, LS6 heads have larger chambers. Im sure the stock 5.3 heads would make plenty of power.
You should be able to exceed a stock LS1 power level with a cam, headers, and some tuning.

shelby987

would it be worth it to hunt down a pair or ported and polished 5.3 heads and change the springs and valves to take the abuse of the new cam?

ArrestMeRed99Z28

iTrader: (1)

Many sponsors have deals where they CNC a set of heads and charge you for the "core" then you send them your heads and they refund the core charge. A lot of people are happy with their 5.3 PRC heads from Texas speed. Add some pace setter headers and a mid range cam and you'll have some serious power.

shelby987

Can anyone give me some ideas on potential power curves for hp/tq numbers with a mild cam, port/polished heads, a healthy exhaust, and a stand alone computer?