377nova

iTrader: (1)

doing a budget 5.3 turbo build. what are good stock heads to run on it. i have a set of stock Ls1 and a set of stock 5.3. which stock head would be better? any suggestions. Or would there be any other stock head out there that would be better to buy on a budget. thanks

Chicago TDP

iTrader: (3)

LOL, I was about to post a similar question!!!!!

Not to steal your thread but I am running 317 heads(71CC) on a stock 4.8L.
If I am calculating correctly, the compression is at about 8.3:1
The car runs and drives fine under boost....no nut at all when not boosting
When the car is just cruising with no boost, it sucks
Putting the car in 6th gear under 50 mph makes the engine struggle
Also, the boost takes a while...with a TC 76..15 PSI does not hit until 4K rpm

I would suggest putting on the set of LS heads
I am in the process of looking for a set of 853's or 241's for $100
That way, the 66 cc chambers will bump me up to about 8.8:1.

So, from my experience (subject to criticism of course ) is run the LS1 heads

NightmareTA

iTrader: (20)

317 heads on a 5.3 will give you 8.5:1 compression. Not sure what the LS1 heads move it to but they do have larger combustion chambers than the 5.3 heads so they will lower the compression a bit. LS1 heads also have bigger valves than 5.3 heads so you'd gain a small amount of flow there. Not sure what the driveability is like when not in boost on an 8.5:1 5.3 since mines not done yet but I'd imagine with a stick it's not going to be too bad if you gear it correctly. I'm running 3.55's in the back so it should drive fine. All depends on the amount of boost you want to safely run on the stock bottom end. Obviously you will get away with way more boost on 8.5:1 than 9:1.

My car is not a daily driver nor will it ever be so I am fine with the lower compression. Make sure you throw on some MLS head gaskets, and ARP head studs probably arent a bad idea either if you plan on boosting 10 or more PSI.

71 chevy

iTrader: (18)

in my humble opinion(and experience), I say, run the stock heads on it. it flows more than enough. spend the money elsewhere.

377nova

iTrader: (1)

its on a 70 nova. I've got ls6 cam and springs. it has 4.56 gears right now will go back to the 4.11. it'll have a built 700r4. another question how big of a stall should i go with. question #2 who would be good to tune it. could a guy like frost get it close with a mail order tune?

377nova

iTrader: (1)

just wanting it to drive decent in town. dont want it to be a dog untill mid- high rpm's.

71 chevy

iTrader: (18)

if you can get it to stall off boost around 3500rpms that would work well

Haddixj

iTrader: (1)

What tuner program are you going with? Are you sticking with the maf? Or going speed density? I am planning the same thing but with a 70 mm turbo so it will spool quick. I'm thinking of going with hp tuners and tuning it myself.

novaflash2002

iTrader: (51)

upgrade your springs past the ls6 springs.

NightmareTA

iTrader: (20)

Me thinks your not going to like even 4.10's on a turbo automatic trans car. Thats way too much gear to get the full potential from the turbo.

As far as the tune, I would ussually not trust a mail order tune on a turbo setup. There are so many factors having to do with the outside weather and air intake temp, etc that you'll never get the true potential with a mail tune. There are so many shops that tune LSx motors these days that you have to be able to find one within a close distance to you.

Chicago TDP

iTrader: (3)

From what I am going through right now with my car, I can honestly say that the lag of the TC76 and the low compression is not the best for the street, PERIOD.
My buddy's wife mini van can spank me up to 30 but then it is all over after that of course. Also, when you are cruising, the car has not nut.

I know that I will be changing heads to increase the compression.
Running at 9.5:1 with 93 octane should not be a problem if you are keeping the car under 700 hp. There are a lot of guys doing it and not having any issues.

And like Nightmare said, Studs and MLS gaskets will keep you from pushing water.

novaflash2002

iTrader: (51)

meth is also (almost) a requirement if you want it to live on pump gas with a good amount of boost to it. I would just leave the stock 5.3l head, swap the springs and cam. boost away. if it blows go pick up another 5.3l for a couple hundo and give her hell again.

pwrtrip75

iTrader: (8)

X2 - I made the mistake putting 317s on my 5.3... no reason to. It will just be more sluggish off boost and spool slower. You wont gain any special ability to run more boost... Stock engine you are limited to the HP it will hold.


9.5-9.6:1 or whatever they are stock is fine.. My 6.0 was stock and I ran 15psi and 25 degrees of timing on E85... 18 degrees on 93 octane... never had any KR.

CALL911

iTrader: (17)

If you are trying to save your pennies, I also would reccomend just staying with the 5.3 heads.