Thread: Brodix IK Heads.

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Hi everyone, just wondering if anyone is or has used the Brodix IK180 heads? Are they good? Bad? Looking to put on my SBC, would like to stay with a 70cc head. Any input would be great.

You have to be careful when comparing heads because you are not, in most cases, told the flow bench protocol that was used to flow the heads. Did the mfg use a 4.00" intake pipe or a 4.060" intake pipe or a 4.125" intake pipe or what? A bigger pipe will allow the heads to flow a higher number. Did the mfg use undercut valve stems or not? Undercut stems will allow the heads to flow a higher number. What depression was used to flow them? The accepted standard is 28" of water on a manometer, but you have no idea if they don't tell you in their literature, although you can call their tech line. Was an exhaust pipe used? A short pipe will allow more flow, rather than no pipe at all. And so on and so on.

If you don't have a lot of time to compare the entire flow regimen of all the heads that you want to look at, or if it is confusing, then concentrate on only one valve lift, 0.400". This is a quick and simple way to compare heads.

A rough rule of thumb is that you would use the cubic inches of the motor and multiply times 0.5 to get the intake runner size for the heads. 355 cubic inches would work well with a ~180cc intake runner head, for instance. A 400 cubic inch motor could use a 200cc intake runner to advantage. A 327 might run well with a ~165cc intake runner.

For a 355 Chevy, I would not be interested in any cylinder head that would not flow at least 200 CFM on the exhaust side, at some point in the valve lift and I like to see 260/270 on the intake side. Now, you can get 200 exhaust on most any manufacturers cylinder head, but not with smaller runners such as 180/185cc intake runners or even 190cc's. A 355 needs the smaller runners to keep velocity up in order to pack the cylinders and make horsepower. Larger runners (200, 210, 220, 230 etc.) will flow 200, but the velocity suffers and the motor may actually slow down from the less dense packing of the cylinders. I see that Dean already knows this because he's looking for 180cc heads for a 355, but I'm expounding on the info for the benefit of others reading this who may not understand that when it comes to cylinder heads, bigger is not necessarily better. Matter of fact, if I wanted a daily driver to haul grandma back and forth to bingo that would operate from idle to maybe 4000 rpm's, I would choose an even smaller intake runner, something like 165cc or 170cc, for brute off-idle torque to pull a numerically-low rear gear and generate fuel economy using a stock or very mild aftermarket cam. Combination, combination, combination.

Brodix IK180
0.200" 138/112
0.300" 188/149
0.400" 234/167
0.500" 243/175
0.600" 245/178
Brodix 1021002, Brodix Small Block Chevy IK Series Aluminum Cylinder Heads | Brodix

Pro-Filer 23 degree 185
0.200" 135 110
0.300" 201 145
0.400" 245 180
0.500" 265 206
0.600" 270 213
SBC 23 Degree Cylinder Heads
Under $1100 fully assembled, ready to bolt on
Available in 64, 70 and 72cc chambers

Airflow Research 180
0.200" 138 110
0.300" 198 158
0.400" 240 190
0.500" 260 207
AFR - Airflow Research 0919, AFR Small Block Chevy 180cc Eliminator Street Aluminum Cylinder Heads | AFR - Airflow Research
No 70cc combustion chamber examples are available from AFR in this runner size, only 65 and 75

With either the Pro-Filer or the AFR heads, 10.0:1 static compression ratio, Edelbrock Performer RPM intake manifold #7101 or Weiand #8150, a 220-225 @0.050" cam, 750 carb, 1 5/8" long tube headers, this motor would easily produce 400 hp and 400 ft/lbs of torque. Actually, I would rather use the Edelbrock #7104 and a Quadrajet, but that's just me.

Dean, before you choose or purchase ANY parts, please allow me to school you on squish/quench if you don't know about them. Setting the squish/quench properly will make or break a motor and usually involves cutting the block decks to a new block deck height when using aluminum heads. Iron heads will work fine with steel shim gaskets to effect a tight squish/quench, but aluminum heads need some compliance in the head gasket, so a thicker composition gasket is used. When you combine the stock piston deck height of ~0.025" with a, for instance, Fel-Pro 1003 gasket with a compressed thickness of 0.041", you end up with a squish/quench measurement of ~0.066", which is too thick to offer a tight squish/quench to control detonation on pump gas.

What we would do is to measure the "stack" of parts to be used, then cut the block decks to that figure (called "zero decking" the motor) and use the thickness of the composition gasket for our squish/quench figure. For instance, if you used a piston that has a compression height of 1.560", a rod length of 5.700" and add in the radius of the 350 stroke (1.740"), we find a stack height of 9.000" with a block deck height of ~9.025". This is the blueprint dimension that was used at the factory when the 350 was built and leaves the piston down in the bore by ~0.025" with the piston at top dead center. When combined with the steel shim head gasket thickness of 0.020", this puts the squish/quench at ~0.045", just on the high side of what us hot rodders like at 0.035" to 0.045". With the piston crown flush with the block decks with the piston at top dead center and 0.041" composition gasket thickness, the squish/quench is 0.041", which will work nicely to prevent detonation on pump gas.

As the piston approaches top dead center, the close proximity of the crown to the underside of the cylinder head will "squish" or "jet" the mixture out of that area, toward the spark plug, creating turbulence that will bust up pockets of lean and rich mixture in the chamber, homogenizing the mix for a more complete burn and maximum power, as well as preventing detonation on fuel quality that might be less than what the motor wants. The "quench" part of squish/quench is the transfer of heat from the piston crown to the underside of the cylinder head so that the cooling system can carry the heat to the radiator. The closer we get the piston crown to the underside of the head, the better the quench and the more heat extracted from the piston crown.

Some fellows run into a problem when they begin choosing pistons. As I stated, the design compression height (wrist pin centerline to the crown of the piston) of a 350 is 1.560". Some piston manufacturers also make a piston with a reduced compression height to allow cutting of the block decks to bring the block to flat to prevent blowing a head gasket due to a wavy surface on the block. If a fellow isn't careful, he can choose these ~1.540" pistons and add another 0.020" to the piston deck height, which of course widens the squish/quench by 0.020", not a particularly good thing. There are a few piston manufacturers who make 350 piston with a little taller than stock compression height. Keith Black, for instance, manufactures their 350 hypereutectic pistons at 1.561"and I have seen some others that produce pistons with a 0.006" to 0.007" compression height over stock. The taller the piston, the less you have to cut from the block decks to effect a tight squish.
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Thank you Techinspector. I was looking at these heads mostly do to the 70 cc they offer. that would put my SCR at 9:5-1 and dynamic at 7:8-1. I was going to use a .039 head gasket as my block is decked to .005 I think that will be ok for the street. I am just wondering about flow of the heads I don't know much about flow numbers. I did see the AFR heads had higher numbers and there 75cc heads would bring my SCR to 9:0-1 aprox. I am using a 270 /278 @50 219/228 519/530 cam from Lunati. Edelbrock performer manifold and a holly 650. Block is bored .030.

Thank you for all the info gives me a lot to think about before I screw something up..

Hi Techinspector, thank you for all the information, i had posted you back but for some reason it still has not shown..

My block is decked piston to deck is .005 i was going to use a .039 gasket.

After reading your post i am looking into the pro filer heads, 72 cc, that should put me at around 9.5:1 SCR abd 7.8:1 DCR..Will the 185cc be a little too much for me? 350 bored .040 over.

thank you again I was a little confused with the Quench so let me see if i got it now..
piston to deck height .005 + head gasket .039 = .044 that should be ok ? Need to stay within .035 & .045 right?

Yep, 0.044" squish/quench will work fine for use with pump gas Dean, although 9.5:1 SCR and 7.8:1 DCR are very conservative numbers for use with aluminum heads.
What's your piston crown configuration or piston part number, head gasket part number and cam part number that you will use? I'd like to figure the SCR and DCR just to make sure for you, if you don't mind. You have several thousand dollars at stake and I'd hate to see you leave power on the table that could be picked up easily at no additional cost using the 70cc heads instead of the 72's and maybe a little different cam. The 185cc intake runners will work great with your 357 cubic inch motor.

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Hi Tech, this is what i have so far.

350 bored .040
Flat top pistons 4 valve +5.00
piston to deck height .005
Lunati 270/278 Hydraulic roller, @50 219/227 515/530
Head gasket .036 thick-- 4.165 bore
Edelbrock performer intake
street demon 625

Was thinking to keep around 9.5:1 for my cam size, and to keep header heat down a little.

Hi Tech, this is what i have so far.

350 bored .040
Flat top pistons 4 valve +5.00
piston to deck height .005
Lunati 270/278 Hydraulic roller, @50 219/227 515/530
Head gasket .036 thick-- 4.165 bore
Edelbrock performer intake
street demon 625

Was thinking to keep around 9.5:1 for my cam size, and to keep header heat down a little.

Dean says he cannot post on the forum, so sent me the following visitor message....

Hi Tech, For some reason i can't post, I PM the administrator to see whats up Regarding my thread on the Brodix IK heads. this is what i have so far.
350 bored .040
Flat top pistons 4 valve +5.00
piston to deck height .005
Lunati 270/278 Hydraulic roller, @50 219/227 515/530
Head gasket .036 thick-- 4.165 bore
Edelbrock performer intake
street demon 625
Was thinking to keep around 9.5:1 for my cam size, and to keep header heat down a little.

I sent him this reply....

At 9.49:1 SCR with 72cc heads, I get 8.345:1 DCR on the Keith Black calculator. Using the 70cc heads, I get 9.69:1 SCR and 8.518:1 DCR, perfect for pump gas using the tight squish that you have engineered into the motor. I strongly urge you to use the 70cc heads.
Let me add some info that you will want to write down and keep for later....
Cam number Lunati 20560721. With the cam installed straight up, neither advanced nor retarded, intake opens 3.5 degrees BTDC, intake closes 35.5 degrees ABDC, exhaust opens 42.5 degrees BBDC, exhaust closes 4.5 degrees ATDC.......
Intake centerline 106 degrees, exhaust centerline 118 degrees, lobe separation angle 112 degrees.
Cam will want a 2500 stall converter, which is perfectly streetable. This will be a great motor, congratulations on your choices.

The motor will want more intake manifold, a high-rise, dual-plane such as the Edelbrock Performer RPM 7101 or the Weiand 8150 Stealth. You can also find this design used, for a little less money, on craigslist, ebay, racing junk, etc. under Holley 300-36 and Weiand 8016. I advise against using the Edelbrock 7501 RPM Air Gap due to driveability issues in colder climes.

Use a 14" x 4" air filter assembly to allow the motor to breathe.

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Originally Posted by techinspector1

Dean says he cannot post on the forum,
.

Not certain why, he might be attempting to add a link to his post, for now have him unclick all of the checkmarks under "additional options" and see if that works.


Bill S.

Dean, looks like Tech has got some good numbers for you. I would like to chip in an item - I am running an air gap manifold here in the southwest. It is fine after it warms up but is such a slobbering beast until it does. Winter of course makes it worse but even in 80 degree weather it takes a few moments. I think you are located in New York and I highly recommend that you use a performer rpm manifold instead. I have read the difference in horsepower is very small and trust me on this, the difference in everyday manners is huge.

Tech, I have a craigslist 383 which I have taken apart and examined. In my opinion the short block was done by one shop and top end added by someone who just ordered from summit by phone and was given different advice than I would expect. I have sold the summit vortec heads, intake, and summit carb and want to put a good long block together. Object is to street drive, coast to coast, have the most usable torque curve that is huge and flat as a board, and be able to jump on Junior and his new muscle car when desired. The motor will be backed by a bowtie overdrive built 200r, 2500 stall, 3.70 rear gears, 31 inch tires, car weight is 3900,, aerodynamics of a brick . I would like for you to take a shot at recommendations for me.
4.03 bore
3.75 stroke
Ross forged pistons -12cc
6.0 rods
pistons are even with deck - zero
I would like to use the pro-filer heads - 185 or 195 what chamber size?
head gasket .041
performer rpm manifold
780cc Holley 3310 with vacuum secondaries.
Retro fit what roller cam?
Premium gas - mile high altitude for home base
Thanks, I am trying to figure this out before getting too far.

Originally Posted by Scooting

Object is to street drive, coast to coast, have the most usable torque curve that is huge and flat as a board, and be able to jump on Junior and his new muscle car when desired. The motor will be backed by a bowtie overdrive built 200r, 2500 stall, 3.70 rear gears, 31 inch tires, car weight is 3900,, aerodynamics of a brick . I would like for you to take a shot at recommendations for me.
4.03 bore
3.75 stroke
Ross forged pistons -12cc
6.0 rods
pistons are even with deck - zero
I would like to use the pro-filer heads - 185 or 195 what chamber size?
head gasket .041
performer rpm manifold
780cc Holley 3310 with vacuum secondaries.
Retro fit what roller cam?
Premium gas - mile high altitude for home base
Thanks, I am trying to figure this out before getting too far.

You know, hot rodding is fun....until you add an overdrive transmission....and vary the elevation between 5000' and sea level.
That's what the factory engineers have to do every time they design a new vehicle, but they have mega-computers to aid them in their choices.
The best I have to work with is some basic math and a modicum of common sense, but I'll do what I can to contribute to the project.

The first thing that must be considered is the gears in relation to cam timing. Your 3.70 rear gear with a 0.67 OD transmission gear and a 31" tire is the same as using a 3.20 rear gear, 0.67 trans gear and 27" tire, so the cam will have to be pretty short to work with that at cruise speed (65 mph @1750 rpm's). I have encountered many fellows who failed to take that into consideration, using a cam that has an operating range of 2500-6000 for instance, when they actually need a cam that has a low operating rpm of ~1500-1600 up to a high range of ~5000. Question is, how do you drive around Henry Hotrod with a short cam? The obvious answer is to use a turbocharger or a blower. Before we go any farther, are you up for that?

The other variable is elevation. If you jet the carb for running good at 5000', the motor will go real lean at sea level, with a very real possibility of holing some pistons. If you jet it for running good at sea level, it will be hog-fat at 5000'. The obvious answer is programmable electronic fuel injection with O2 sensors in the header collectors and using a cam with a 114-116 lobe separation angle, like the OEM's do. Again, are you up for that?

.

Originally Posted by techinspector1

You know, hot rodding is fun....until you add an overdrive transmission....and vary the elevation between 5000' and sea level.... The other variable is elevation. If you jet the carb for running good at 5000', the motor will go real lean at sea level, with a very real possibility of holing some pistons. If you jet it for running good at sea level, it will be hog-fat at 5000'. The obvious answer is programmable electronic fuel injection with O2 sensors in the header collectors and using a cam with a 114-116 lobe separation angle, like the OEM's do. Again, are you up for that?

Not trying to hijack, but I remember a sign at one of the real "service stations" (the kind with mechanics on duty...) back in the early '60's as we drove the road approaching Pike's Peak in Colorado, "Get Your Carburetor Adjusted Here". We were from south Missouri, elevation about 1000' ASL driving at about 6000'ASL and getting ready to be pushing 14,000'. I remember that I couldn't tell the car was running at idle at the top, as it was only turning about 250rpm, and pressing on the gas got a sloooooow ramp in rpm's, zero "snap" to the throttle. I wondered at the time how many people paid a few bucks for smaller jets to drive in the mountains, then wondered why their car ran like crap when they got back home.... We didn't stop, but I expect the mechanic told his customers to stop back in before they headed home, and he'd re-tune them back to flatland specs using the jets he removed a few days before....for another few bucks, of course.

Real world is fun, huh?


Your questions, on a blower, yes. High interest in a M122 Magunson adaption.
On fuel injection, cost plus a strong history to loving carbs slows that desire down.


However, let's talk and see what can be done. Can I get the compression low enough for a blower with the pistons/zero deck?
Nothing is set in stone including my likes/dislikes and am open for education. Have at it.

Not a hijack at all Roger, I would welcome any and all comments from you other fellows. The more minds we put toward the problem, the better chance we will have of working out a solution.

As of now, I would be thinkin' Pro-Filer 195 heads with 72cc chambers and a Fel-Pro 1003 head gasket for a 9.41:1 SCR. Blower Drive Service says you can run 4 lbs of boost into the motor on pump gas at 9.5:1, so that would be your boost limit, unless you used a good water/alcohol injection unit, such as this....
Snow Performance Boost Cooler Stage-2 Water/Methanol Injection Systems 20010 - Free Shipping on Orders Over $99 at Summit Racing
With that unit, you may be able to run up to 7 or 8 lbs, I'm not sure and would have to counsel with Blower Drive Service about that.

Using a blower, you wouldn't need to worry so much about cam timing, you just cam the motor for what operating range you want and let 'er rip.

I wouldn't try to do any of this without EFI, such as the FAST EFI. Read through the support forum here....
Electronic Fuel Injection Help Fuelairspark.com

In the end, it may be cheaper to sell your place and move to the flatlands. I mean, is it really going to be worth the cost and jumping through all the hoops?

.

turbocharged diesel to haul it down to lower altitudes-