I keep hearing about people using the 5.3 heads. And all the posts are about who to get em from what stage, what valves etc. But i cant find what it is about that head that makes it so desirable? Larger ports, bigger stock valves, smaller chamber etc etc?? Why is the 5.3 head such a popular choice?

 

If I had it to do over I would have went with ported LS1 or LS6 heads instead of the 5.3.

Reason 1: 5.3 heads will raise your compression and if you ever decide to go with a turbo, supercharger or nitrous then the added compression will hurt you.

Reason 2: With 5.3 heads you can't go with as large cam as with LS1 or LS6 heads.

If you don't mind needing higher octane gas, you plan a moderate size cam and don't ever plan on going bigger then 5.3 heads could work. Just don't go with the Patriots. They caused me a lot of problems. With in 2 years, three valves went bad and I had to spend a lot of money fixing them. Plus my horse power increase was little to none until I paid the money to have them redone.

The added compression will give you about 5 extra horse power than the LS1 heads. Also if you do, go with 5.3 heads get at least stage 2 heads with 2.02 and 1.57 valves.

My choise if I had it to do over would be the new Dart heads with 225 runners and 2.05 and 1.6 valves. Also my cam would be much larger than the one I chose.

Best of luck,

Al

 

I'm getting the Patriot Stage 2 5.3L heads. 2.02 and 1.57 valves.

 

Compression Compression Compression! That 5.3 head 862 casting is a powerhouse on the 5.7 motors. You get the right stuff done to them and you will see alot of power.

 

Nitrous loves compression, so you assumption is incorrect

sure you can, it all depends what size valves you are using.

FYI, I do not think you quite grasp what is a 4.8/5.3L head.

1- Even ported they are 215>220 cfm int ports which promotes velocity.
2- They raise compression while keeping stock PTV.
3- You can recess the valves to increase PTV with bigger valves.
4- Cost efficient (that is untill the LS2 casting came along)
5- Ported properly, they are capable of over 300 cfm flow (with small ports).

Yes the LS6 casting is better, but was too expensive until the LS2 casting came along in 2005. (both are 243's but with different valves)
Nowadays that is the budget casting of choice.

 

Mark, You ran the PRC 5.3 stage 1.5's correct?

 

Stage 2.5's (2.04 intake/1.575 exhaust), race prepped.

 

Poor LS1! You decided what route you are taking 2nd time through? Headwise that is....

 

We like it because the small chamber and runner's give us some metal to shape the port the way we want to to get good airflow and still keep it relatively small to promote strong mid range power. Also the small chamber is a bonus because compression makes power. The drawback is that the valve drop is .030 less than the 5.7 head from the start and when you add a 2.02 or bigger valve you are usually limited to cams under 230 @.050 unless you flycut the pistons.

 

Forget the flycut! That cam in my SS w/ the combination of a 5.3 head would make my valves hit my wrist pins! eventually....

 

I dunno about that but mine accepted a 232/234, .595/.598 113+0 with safe margins, that is with 2.04/1.575 valves.

I will be using these heads again.

 

Good hearing from you PredatorZ

 

Hi Sheets, you too have a 232/234 with 5.3 heads.
It really depends on the valve events.
I know that a 112+4 will not fit mine.
Good to see you around again Sheets.

FYI a 233/239 113+0 will also fit with recessed valves
Thickness of valve seats has to be acounted for, some valves eat as much as .020 PTV due to their seat thickness.

 

Nitrous loves compression, so you assumption is incorrect

Quote:
Reason 2: With 5.3 heads you can't go with as large cam as with LS1 or LS6 heads.


give this man a drink, just goes to show you don't believe everything online. I strongly agree, no2 loves compression.

Avise, call some professionals and get some ideas, plan ahead, do research here as MOST are knowledgeable, but you can easily get incorrect information as well, heads are a big decision put a good amount of thought into it. Call MTI, TSP and Thunder, get their recommendations, then bounce it off here, this way you can get the best fit for your own plans and future mods.

Pedator z has got great info here.

 

That's why I said "usually"

 

I just got all my parts delivered so I can't speak with proof yet...but thanks to guys like you and others I'm confident things will go together exactly as planned.

FYI, I did limit my intakes to 2.02" to work with the F14 (232*/234* .599"/.600") cam. I'm running at 4,800ft above sea level and I need the bump in compression the 862 castings offer.

PredatorZ check THIS out. We didn't do alot to the chambers, but I'm under the understanding there's not alot to be gained there. The valves were recessed and the ports flowed and matched. Chambers came out right at 62cc.

The guy that did the work ran them on the bench compared to a stock LS1 head and was very happy with theimprovement in flow under .600" He was working hard to maintain good flow under the curve and not just peak numbers.

I won't know the full results until I get it all together and start dyno tuning.



You see alot of people milling 241 casting .030" to get compression up. The reality is a 5.3 head is basically a 5.7 head with a .030" lower combustion chamber. So you get the CR bump without the valvetrain geometry re-alignment of .030" Either way will work. It's all about budget, availablity and your long term goals.

 

So an F14 will work with 2.02 and 1.57 valves??

 

Yes if the VE's are right or valves are recessed or both.
That is with .053/54/55 gasket.

 

And maybe with a thinner gasket, but the only way to know is to measure PtoV during the build.