ls1trans-am

how much hp can i expect to gain from 5.3 heads off a 2002 truck?

i have a stock ls1 now my plan is to get to 475-500 rwhp with as little cash as possible...that being said i have already got 1.75 to 3 headman headers an ls6 intake and catback exhaust going on the car asap just wanted to know what you all thought i know a cam is in order i was thinking the hpe megadeath cam from chucks and a tune would do it right just wondering

parks450

iTrader: (17)

Ummmm you better have a good budget to hit those numbers. A cam and exhaust won't even get you to 400. The heads off that motor aren't any better than yours, you will need something like a 225cc head. Which is $$$

badazz81z28

iTrader: (6)

Yea, thats going to be tough...even with AFRs and a wild cam, doubt you will get there. You need a stroked LS3.

garygnu

some good ported cnc heads and a big EPS cam can make 475+rwhp.you will need a fast intake and alot of money.check Texas Speed for heads and other needed top end parts.you will bigger injectors and better flowing fuel pump.

salemetro

iTrader: (5)

Better be planning on a forged bottom end for those numbers.

ScottyBG

475-500 rwhp on as little cash as possible = spray. Those numbers on just motor are costly. 420-450 would be a much more reasonable goal, if budget is of concern. Some ported factory heads and a mid sized cam can get you there if your a M6. Don't get obsessed with building a dyno queen if your going to drive the car on the street. A midsized cam will loose on the dyno to a donkey dick, but can be quicker on the street. If your stuck on a 475-500 rwhp goal, the 5.3 heads would not be a good choice, you need to move further down the page.

91sonomast

Go forced induction

vettenuts

iTrader: (4)

There was an advantage to the 5.3 heads when worked correctly. As a straight replacement you may lose power. Look for some 243's and send them to AI.

ls1trans-am

Ya its a street car actually my DD, i am shooting for high 11's really low 12's I mean really low like on 83 octane instead of 93 octane...SO the hp dont matter as much as the drive ability, but i would really like for it to be high power all motor.....

parks450

iTrader: (17)

You most likely won't get there without 93. Also that big investment would probably blow up on 83 if you have higher compression.
The way your talking you will not have something reliable, You won't get their cheap unless you use spray simple as that. You may want to do some searches on here. There are a few builds like what you want to do, and their not cheap. So get that out of your head

91sonomast

Even the 5.3 heads will make some good power if sent to AI, but you're gonna be out $1100 at the very least when you send them to AI.

v84life

You will need a chunky cam and about full boltons to break 400whp I would suggest spray because unless you go full forged bottom end and pull out all the stops you wont get near 500whp all motor. I made 411whp on motor with cam, bolt ons and a fast 78 on stock 241 heads pretty respectable but not many will break 400whp just cam and bolt ons.

ls1trans-am

Damn this is all very disappointing...lol well guess its back to the drawing board......

Che70velle

iTrader: (6)

Locate yourself an ly6, or equivalent 6.0 for cheap. There are plenty of them out there. The weight disadvantage can be off set with a tubular k member, and then you are an intake, and camshaft away from 500ish hp. Drivability is king. Will this route be cheaper? Do your homework.

redtan

iTrader: (5)

You want to use 83 octane? In what country are they selling that at regular gas stations?

ls1trans-am

In the great country of Texas......but i guess i wasn't clear i meant that if i had to be cheap on the day of my track run (after mods) an 83 octane is all i could afford i would still run in the upper 11's.....not to say i will do that just a thought plus i run 93 octane all the time .....ima do some searches on the ly6 and see what i can come up with thanks che70velle

PREDATOR-Z

The difference between a LS1 and a 6.0 is only 0.3L or aprox. 14cid
Hardly what will make a huge difference cam only. Now a LS2 6.0 with ported heads and cam+ bolt ons then yeah 450+ is readily available on M6 rides.
Look at my sig with stock cubes 350ci. but believe me that level ain't cheap.

joeyagls1

243 heads are the best you can get.

redtan

iTrader: (5)

Wow, did not know there was such a thing as 83 octane. How much does it cost per gallon vs. say 87 and 93?

IMO, you're going to make a lot of sacrifices to run 83 octane, both in power and in other parts needed to make up for that loss in power. Makes me think that saving a few bux a fillup is not worth all the power you are missing.

garygnu

you only need 380+hp to run 11s,if your combo is well though out.some 243/799s with a valve job and a good cam can make 440+hp.your don't need a big cam with good heads.the cam should match your whole combo.