N20zuki

Ah yes, "use the search button" unfortunately I am not in the same boat as the 100 other 5.3 more power threads especially the one with the kid wanting to spin a 5.3 to 7500.

I have a LM7 from a 02 Avalanche in my 88 Monte Carlo SS, strapped to a T56. I plan to strap her to a dyno soon to get some baseline numbers to see where I stand.

But the mods to the motor now are, LS2 timing chain, LS6 oil pump, Efans, Midlength 1-7/8 headers, true dual exhaust with X pipe, and a cold air. Yes I am aware these are not impressive but its to keep out the chiming in of do those things.

I am running the stock intake manifold for now, hope to swap to a TBSS intake later on, No I do not want a car intake, I built this car to Autocross and road course events so I would like low end power with the long runners.

Near plans would be (since I have a line on a set) are PRC Stage 2.5 5.3 heads, and I have no idea on what cam to choose but was told to look at the TR226 and TR228 as an option. Im wondering how much power can be squeezed from this motor with that head and cam combo, Yes I would love to do a 6.0 but the prices people want are outrageous. The car weighs in at 3400lbs so I figure 400-420whp would be nice.

Whitecrewcab

iTrader: (2)

Unless you are gonna put flat top pistons in it, have the heads milled. When they put the bigger valves in, they open the chambers way up. Being that it's a 6 speed in a lighter car, you can definitely get away with more cam, but if you want to autocross it, you will need to stay somewhat conservative to keep the low end. My 218/224@.050 cam peaks at 6300 if that gives you an idea of the powerband. I would look at the 220-224@.050 range for what you want to do with it. My truck made 300 at the wheels using second gear, if I had been able to use 3rd, it would have been higher. I figure with ported heads and about stock compression, I should be able to see 340-350 at the wheels.

N20zuki

The PRC heads are still 62CC like my stock heads... So the compression should stay the same, I was kind of hoping to be able to see 380ish to the wheels with the stock intake till I saw to a TBSS or a Maggie...

Whitecrewcab

iTrader: (2)

The 706's only have a 58cc chamber. I was going to do the same swap, but I wanted to up the compression in the truck, even milled, they could only get back down to a 58cc chamber. It will probably still make more power upstairs because of the airflow, but with the low compression, the bottom end gets soggy.

gagliano7

I would up your compression with some heads. The LM7 has 9.5:1 compression so you have room for improvement. The most popular cam I have seen on here for power is the 220/220 cam. Do a search and you will see plenty of threads on cams to give you an idea.

N20zuki

Like I stated in my first post the search didn't net what im looking for. I am not building a motor for a 5000lb truck but for a 3400lb car, Also not running a auto as I am running a T56.

Ill have to double check what heads my buddy has that I am buying as they are sold in 58-62cc variations and I hope they are 58cc to keep the compression up.

Whitecrewcab

iTrader: (2)

You also said that you didn't want to spin it to 7500. We are trying to show you options within those limits. You are working with only 325 cubes, it doesn't take much camshaft before you start spinning it lots of rpm to make power. Anything much over a 220-224@.050 and you are knocking on a 65-6700 rpm power peak, shift point will probably be 7-7200.

Chevy_King1500

iTrader: (7)

use google search, you will find answers you just have to dig and read