15*heads vs brodix 18x
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Registered User
Joined: Sep 2002
Posts: 1,942
From: kitchener/Ontario
15*heads vs brodix 18x
Just for fun here
I would like to get some more info on the heads above..
1st- What other companys make 15* heads and is one better then the other
-where to get them "used"??
-what to look for
-what kind of number are people getting out of these heads
-$$$
-what kind of lifters,rockers,needs
18x
-where to get them "used"??
-what to look for
-what kind of number are people getting out of these heads
-$$$
-what kind of lifters,rockers,needs
-could the 18x be enough head do what mindgame is doing..383,Street SR cam, High 9s N/A
Lets just compare the heads
-flow numbers
-valve train parts
-intakes
-headers
-HP & TQ numbers you would see
What would be the better head,
Just though i would put this out there and see what people have to say
I would like to get some more info on the heads above..
1st- What other companys make 15* heads and is one better then the other
-where to get them "used"??
-what to look for
-what kind of number are people getting out of these heads
-$$$
-what kind of lifters,rockers,needs
18x
-where to get them "used"??
-what to look for
-what kind of number are people getting out of these heads
-$$$
-what kind of lifters,rockers,needs
-could the 18x be enough head do what mindgame is doing..383,Street SR cam, High 9s N/A
Lets just compare the heads
-flow numbers
-valve train parts
-intakes
-headers
-HP & TQ numbers you would see
What would be the better head,
Just though i would put this out there and see what people have to say
Registered User
Joined: Jul 1999
Posts: 128
From: Tx
GM, GM/Pontiac and Brodix are your choices in 15 degree castings. For myself, better or worse doesn't really mean much outside of wedding vows. I'm mainly concerned with the level of work I can put into an untouched casting. If the material is there, I'm a happy camper regardless of the name on the casting. I don't like the name, I machine it off. 
There are a few reasons that I prefer the Brodix casting over GM but I would rather keep the reasons to myself. From the raw casting, I cut all portwork, combustion chambers, etc..
From a flow standpoint, any of these cylinder heads have volumetric flow capabilities in excess of 400 cfm. Enough flow to sustain the largest and highest speed small block chevys.
You refer to the 18x Brodix cylinder head?
It is a good head, but it isn't in the same league as the true 18 and 15 degree castings. If you are going to drop the dime, you might as well utilize the better castings. The 18x is a casting of compromises centered around the use of 23 degree componentry. I don't care to get into all the ideosyncrasies.
MG's heads are unique. I know them well enough because I did all the machine work on them. I've logged countless hours of port and seat development with GM race castings over the years. With that comes a few tricks to making them work real well. Don't make the mistake so many make in putting too much faith in flowbench numbers. Flowbenches are simply comparison tools for port developers. Kind of like a go and no-go guage. MG's heads have much more going for them than good flow.
You are going to be better off budgeting in a custom intake manifold utilizing a near-stock location type throttle body. Anything else is going to present a packaging problem on a 4th generation car. The available cast intakes are going to put you right through the hood. So, unless you are building a race car with snorkel setup your options are few and far between. Plan carefully.
As for output, I have been a part of small block programs making better than 1,000 bhp, normally aspirated, with similar heads. 600-700 bhp is very feasible for street small blocks limited to pump gasoline and 7 thousand rpm. Getting the big numbers with mild camshaft timing is a bit more challenging.
Take care.
There are a few reasons that I prefer the Brodix casting over GM but I would rather keep the reasons to myself. From the raw casting, I cut all portwork, combustion chambers, etc..
From a flow standpoint, any of these cylinder heads have volumetric flow capabilities in excess of 400 cfm. Enough flow to sustain the largest and highest speed small block chevys.
You refer to the 18x Brodix cylinder head?
It is a good head, but it isn't in the same league as the true 18 and 15 degree castings. If you are going to drop the dime, you might as well utilize the better castings. The 18x is a casting of compromises centered around the use of 23 degree componentry. I don't care to get into all the ideosyncrasies.
MG's heads are unique. I know them well enough because I did all the machine work on them. I've logged countless hours of port and seat development with GM race castings over the years. With that comes a few tricks to making them work real well. Don't make the mistake so many make in putting too much faith in flowbench numbers. Flowbenches are simply comparison tools for port developers. Kind of like a go and no-go guage. MG's heads have much more going for them than good flow.
You are going to be better off budgeting in a custom intake manifold utilizing a near-stock location type throttle body. Anything else is going to present a packaging problem on a 4th generation car. The available cast intakes are going to put you right through the hood. So, unless you are building a race car with snorkel setup your options are few and far between. Plan carefully.
As for output, I have been a part of small block programs making better than 1,000 bhp, normally aspirated, with similar heads. 600-700 bhp is very feasible for street small blocks limited to pump gasoline and 7 thousand rpm. Getting the big numbers with mild camshaft timing is a bit more challenging.
Take care.
Registered User
Joined: Nov 2001
Posts: 2,985
From: In a house by the bay
The catalogs will tell you some specifics. Or you can find most of the information on the web.
Won't tell you where to get them used, sorry. You'll have to shop around ebay and online 'used' race parts liquidators like Muscle Motorparts.
You'll have a much easier time finding an 18º or 15º race head than finding a used 18x. Most guys don't opt for the 18x for the reasons Chuck mentioned. The head is just not going to be competitive in a class with true race heads.
Alot of guys are going to sb2 and canted valve heads, so people are always selling off their old stuff. Lots of deals to be found. You might as well be ready to buy a set of custom headers if you go this route. That and an intake. So get out the credit cards.
-Mindgame
Won't tell you where to get them used, sorry. You'll have to shop around ebay and online 'used' race parts liquidators like Muscle Motorparts.
You'll have a much easier time finding an 18º or 15º race head than finding a used 18x. Most guys don't opt for the 18x for the reasons Chuck mentioned. The head is just not going to be competitive in a class with true race heads.
Alot of guys are going to sb2 and canted valve heads, so people are always selling off their old stuff. Lots of deals to be found. You might as well be ready to buy a set of custom headers if you go this route. That and an intake. So get out the credit cards.
-Mindgame
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