Im going to be running a forged 346 and i plan on running the T-rex cam. ive been debating on weather or not to get the stock heads ported on. Well i have recently came acrooss a set of of 5.3s stage 1.5s for a real good deal. will having the 5.3s be a good head for the t-rex? or should i just stay with the stockers.

 

Ported 5.3's will flow better than the stockers.

 

i am aware that the ported 5.3s will flow better but will i be picking up much if any power with this head. Having the stockers ported is an option as well. im just wanting to get some compression and i can with the 5.3s if i was to stay with stock ported heads then i wouldnt get much more then stock compression with the piston and head gasket that i will be running

 

if you are getting a great deal on them then go for it if thats what you want. But just depends if you want to spend money for better heads or not.

5.3 is a great budget head but for ported stockers the 243/799 head is the way to go

 

flows better and higher compression = more power

you say you're aware they flow better and that you know they will increase compression but ask if you will pick up any power, I guess I dont get it.

And as far as someone telling you which head will be better you would have to post all the specs etc... of each head, if you are asking if the ported smaller chamber 5.3's will give you more power than stock then I think you need your med's. Who's 5.3 stage 1.5's, what are your stock heads, how extensive on the porting of your stockers if you did port them etc etc etc.

Your question leaves too many questions to be asked. Or maybe I am just being detailed about answering your question, anyways...



if its cheap to get a set of worked over 5.3's then I think I would go that route.

 

I agree with what's been said above. A ported factory head can rival the best aftermarket castings if it's done by a master. Compression is your friend, but remember, thinner head gaskets and small cc chambers shrink piston to valve clearance. Be prepared to flycut valve reliefs in your pistons if running the T-Rex. Also budget for a really good tune (not just a WOT tune).

 

TEA stage 1.5 ported 5.3 heads milled .010 the stockers are 853s i think. if i was to have them ported it would be nothing short of excellent. we have a gentlemen locally that hand ports and out flows 12 axis cnc machines. as though it will be his first ls1 head i have full conffidence in him. i know im leaving some gaps here and there.... i know the t-rex is made for stock heads. but im wanting to get a lil more compression and a lil bit better flowing head as well. i will be running the t-rex for sure and im will be running a mahle 3.898 -4cc valve releafed piston on a 6.125 callies rod and stock crank

 

1.5
Flow Data
LS1 5.7 Stage 1.5 ````LS1 5.3 Stage 1.5
Lift Intake Exhaust ````` Lift Intake Exhaust
0.1 66.8 52.1 ````````0.1 67 53.7
0.2 138.6 108.5 ```````0.2 140 122
0.3 200.4 160 ````````0.3 203.5 172
0.4 248.5 209.3 ````````0.4 250.6 218.2
0.5 283 236.9 `````````0.5 288.9 244.4
0.55 295 247.4 `````````0.55 302.9 254.7
0.6 300.4 255.3 ````````````0.6 313.7 260.5


CNC Port LS1 5.3 and 5.7 Head to Stage 1.5
3.900� Combustion Chamber
Competition Multi-Angle Valve Job
Blend Valve Job
Mill Heads to Customer Specs
Flow Intake and Exhaust Ports
Heads Cleaned, Set Spring Heights, Assemble, Seat Pressure, Installed Height, and Coil Bind
Ferrea 2.020 Intake Valve
Stock LS1 1.550 Exhaust Valve (REV 1.57� Exhaust Valves are also available)
Standard TEA .650" Lift Dual Spring� (Comp 1.250� 921 and Comp 1.440� 978 are also available)
TEA Titanium Retainer
TEA Locators
GM Locks
GM Intake and Exhaust Valve Seals



i guess that the graphs tell it all right there. the heads im looking at are milled .010

 

Ok so you say the T-rex is built for stock heads ( I dont know what you mean by that exactly but theoretically the cam is built to put more air in the cylinders and that is all the cam knows ) so that being said if you do anything to help that cam get more air ( or rather get more air to the valves the cam is opening ) easier then of course power will go up, no one can tell you how much, if you had a detailed spec sheet of the heads someone as knowledgeable as Patrick G could guess-timate a gain. I would definately say if one part of your setup is chocking it would be the heads intake etc, that cam surely can pull more air than the stock heads can provide.

And yes as stated compression is your friend but it would be better to raise your compression by going to a 243 casting that has a quench pad that lowers the chamber volume and results in higher compression rather than cutting way down on the head, because like Patrick G stated, then you run into piston to valve clearence issues, and thats leaving out all the good things that quench pads do for high compression and detonation damnpening.
Im not even going to go into smaller chamber/vavle shrouding because I dont know what you plan to do or what is done to the chambers and I definately am no guru or genious in this matter.


Sorry I dont know much about all the different castings, but the 853's are stock poopy just like the 241's. I picked up a set of 243's with 30k miles for 200$ two days ago and will be using them.


A point gained in compression yields 4% increase in power ( believe it was 4 or 4-5 )


But if you can then also add a quench pad thats just that much more compression you can run safely without the worry of knock.


If any of that was incorrect feel free to correct me, im pretty tired and didnt proof read it very well. Please if any of that is mis info point it out.

 

after just seeing those specs, that looks like a pretty good head.

If they are a real good deal I would jump on em, if you dont let me know lol.

 

You definately want to be careful with p/v on the T-Rex. It's definately a great camshaft, but p/v is pretty tight for putting larger valves in a head. Aftermarket valve angle heads will give you extra clearance or something like the PRC Stage 1 LS6 heads will also do really good. We've installed the PRC LS6 Stage 1 heads on a T-Rex car & had it make 490rwhp! It gained 40rwhp & the car runs completely awesome!! It's a great head for $1000 a pair!!