Rectangle port heads on 5.3?
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Rectangle port heads on 5.3? I know mast makes a "small bore" rectangle port head. Is it worth running them over an aftermarket cathedral or CNCd 243 castings? What are the other benefits besides more intake options? Motor will be stock bottom end with a healthy cam that makes top end power with a sacrifice in the low end. Also thinking about upping the compression ratio and running pump 93 in conjunction with water meth. Also considering a small shot of nitrous for track use only.
Thoughts? Suggestions? Recommendations?
Thoughts? Suggestions? Recommendations?
Given the size of the bore and the size of the valves needed to fit, I would not bother with rectangle port heads.
Ger yours ported by AI and they'll be plenty for the little ol' 5.3.
Ger yours ported by AI and they'll be plenty for the little ol' 5.3.
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Thanks guys, I was planning on just doing that with the 243's but I really want to do something different. the only intake option I have with the cathedral heads is a stock LS6, but with the rectangle ports their are a few aftermarket options that I believe would work, as well as the stock LS3 90mm TB setup.
Any other thoughts?
Any other thoughts?
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I do plan on having a very healthy cam, as agresdive as i can go for a DD. but i do not plan to run a fast no matter which heads i choose. I have been told by many people that they arent worth the money, and cause problems when running with boost which might be in my future plans.
Im thinking about the modular holley intake, as well as a few others with rectangle port only.
Im thinking about the modular holley intake, as well as a few others with rectangle port only.
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Verdad Gallardo So if you don't plan on ever running an FAST intake, then why do you say that staying with cathedral port heads limits your choice of intakes? Do they not make carb style intakes for cathedral ports?
Have those style of intakes only been invented since the advent of the square port head in 2007 and did not exist before?
Have those style of intakes only been invented since the advent of the square port head in 2007 and did not exist before?
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The aftermarket no longer makes most of the cathedral style intakes since the better rectangle port heads were released in 07. Im not going to use a carb style intake, the elbow required wouldnt fit.
Last edited by V8ImpSS; Apr 9, 2012 at 09:33 PM.
Redtan, what he is saying is the fast intake will not fit. No matter what style heads. With cathedral port heads, the only stock style intake that is worth a **** that will fit under the hood is the ls6. With rectangle port heads, you have the ls3 or l76 that flows very well and fits.
With the large port of the ls3 style heads, even the small bore ones, will give you more problems than it's worth on a 5.3
You will be better off with cathedral heads, ls6 intake and a cam to match everything. It will still be a strong runner and more driver friendly.
BTW, I hope transmission upgrades are in the future as well.
With the large port of the ls3 style heads, even the small bore ones, will give you more problems than it's worth on a 5.3
You will be better off with cathedral heads, ls6 intake and a cam to match everything. It will still be a strong runner and more driver friendly.
BTW, I hope transmission upgrades are in the future as well.
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Redtan, what he is saying is the fast intake will not fit. No matter what style heads. With cathedral port heads, the only stock style intake that is worth a **** that will fit under the hood is the ls6. With rectangle port heads, you have the ls3 or l76 that flows very well and fits.
With the large port of the ls3 style heads, even the small bore ones, will give you more problems than it's worth on a 5.3
You will be better off with cathedral heads, ls6 intake and a cam to match everything. It will still be a strong runner and more driver friendly.
BTW, I hope transmission upgrades are in the future as well.
With the large port of the ls3 style heads, even the small bore ones, will give you more problems than it's worth on a 5.3
You will be better off with cathedral heads, ls6 intake and a cam to match everything. It will still be a strong runner and more driver friendly.
BTW, I hope transmission upgrades are in the future as well.
Some 5.3's can be bored out to LS1/6 spec giving me a 5.7. Are the cathedral heads worth it then? I want the most power possible the 1st time.
Are the cathedral heads worth it then? I want the most power possible the 1st time.
And surely you can find a holley type intake for cathedral heads if you don't like the stock style intakes. Yeah they don't make them anymore, but it's not like all just dissapeared off the market...
The only cathedral intake that is no longer made is the fast 78/90/92. They were replaced by the 102. That does not mean they are no longer avail. They go up for sale quite often but get snatched up quickly.
The other companies that made the other cathedral intakes still make them. BBK/Holley one is avail, and the Prof Products. You can also use an LS2 intake and have it ported and see good gains and still use the 90mm tb like you want from the LS3 intake. Or you can use a carb style mani with fuel injector bosses and a 4 bbl TB on it for an old school look.
The one that sees mixed reviews the most is the Edelbrock Pro Flow XT.
The other companies that made the other cathedral intakes still make them. BBK/Holley one is avail, and the Prof Products. You can also use an LS2 intake and have it ported and see good gains and still use the 90mm tb like you want from the LS3 intake. Or you can use a carb style mani with fuel injector bosses and a 4 bbl TB on it for an old school look.
The one that sees mixed reviews the most is the Edelbrock Pro Flow XT.
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The 4 bbl TB would look cool, but it would be a bitch to get it to work with my ram air hood. Are the BBK/HOLLEY/Prof Products stuff going to give me gains over an LS6 or ported LS2? Should I just get a 90mm ported LS6?
Are the BBK/HOLLEY/Prof Products stuff going to give me gains over an LS6 or ported LS2? Should I just get a 90mm ported LS6?
Porting an LS6 is not really going to do anything, and getting a 90mm snout on there is expensive. A very well ported LS2 manifold with its 90mm opening performs just as well as a stock LS6 and I would venture is your best bet as far as a stock style intake is with a 90mm opening.
There are small bore rectangular port heads. I think MAST makes them.