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PROMAXX 200 HEADS FOR SBC CHEVY ENGINES.
64cc COMBUSTION CHAMBERS, 200cc RUNNERS, STRAIGHT PLUG. SETUP FOR HYDRAULIC FLAT TAPPET CAMS.
Incredible flow numbers, outstanding quality.
The build quality exceeds that of all low cost aluminum heads on the market.
The hardware setup on these heads is for use with hydraulic flat tappet camshafts up to .550 lift. See our other listings for hardware setups to accommodate hyd. flat tappet cams and solid roller cams.
These heads are highly recommended for use on sbc 350, 383, and 400/406 engines. They are the perfect runner size for mild to Pro-street buildups.
The ProMaxx heads used on a 350 engine build will produce up to approx. 415 hp. on pump gas when combined with a hyd. flat tappet cam in the 525 lift range, a single plane intake, compression ratio at approx. 10.0:1 or more, and a 750 cfm carb. When used on a 383 stroker engine, the horsepower and torque numbers will increase dramatically. The ProMaxx heads have much more potential than what is mentioned above, when setup with a hyd. roller cam.
The hardware setup on these heads is for use with hydraulic flat tappet camshafts up to .550 lift. See our other listings for hardware setups to accommodate hyd. roller cams and solid roller cams.
We have complete top end hardware kits available for the ProMaxx heads in our other listings. The kit has the correct head and intake gaskets, head bolts with special washers, and stainless intake bolts. The part number is TEK-1003-1206, or for those that favor the MLS multi layer style head gaskets, part number TEK-5219-1206, or any TEK kit that has the 1206 part number in it. The first number is the type of head gaskets, and we offer around 5 different head gaskets that will work with the ProMaxx heads. The 1206 is the intake gasket part number, and that is mandatory for use with the sbc ProMaxx heads.
Please note: Due to a high volume of sales at this time, these heads may take up to 3 business days to complete and ship. Please let us know if you are under a time constraint with this order, and we will do our best to accommodate your request.
These heads have extensive bowl blending work performed.
After extensive testing, we tore down the Promaxx heads on our 383 house engine and checked the guides and seats, as this was an area we were more concerned about than any other aspect of the head, and found zero wear. Many of the dyno passes were run to 6500 rpm as the large cam needed 6300-6400 rpm for peak power, and you must run past this to determine the falloff point. Considering the size of our largest hyd. roller cam, it was very impressive to see zero wear issues to any degree with the heads or hardware. We made a good 25 passes with the big cam, trying out different carb sizes, jetting, intake manifolds, timing settings, etc.
The hardware setup on these heads is for use with hydraulic flat tappet camshafts up to .550 lift. See our other listings for hardware setups to accommodate hyd. roller cams and solid roller cams.
TWO YEAR WARRANTY, UNLIMITED MILEAGE.
The warranty will cover the castings, seats, and all hardware.
Note from Skip White, President:
We certainly know where to draw the line with low end products, and we continue to eliminate parts that we once accepted that eventually had problems. Sometimes it's not that a particular product has or will have a problem, but something better comes along. When the NKB heads came to us, we thought that was about as good as it gets in the world of low cost aluminum cylinder heads. Then, ProMaxx came along. The price is a bit higher than our NKB heads, but for those wanting to move up to the next level of quality, reliability and performance, we think they are the best choice.
We have tested these heads extensively before introducing them into our product line. Considering the price is considerably less than any of the high end name brand heads, we feel these to be a great value. We offer the ProMaxx heads as an upgrade on our 350, 383 and 406 engines. The performance has been outstanding on every combination we have tried. In the rare event you have issues with the ProMaxx-200 heads, the problem will be addressed. The warranty for these heads is two years, vs. one year for the NKB heads.
We have sold many sets of the ProMaxx 200 heads as upgrades to the NKB heads that came standard on our 350, 383, and 406 engines. This gave us a chance to see how they perform on different combinations compared to the NKB heads. When using any of our four popular cams, the ProMaxx heads outperformed the NKB heads. The most important aspect of the ProMaxx heads is their outstanding quality and workmanship, leading to reliability and endurance beyond any of the lower-cost heads we have sold in the past, including the NKB heads. Thatâ€™s why ProMaxx is our choice for the best set of heads for the money.
If you receive the heads and don't think what weâ€™re saying is 100% true, we will give you a full refund. If you were to take these heads to a machine shop to have them installed on an engine or just to have them looked over, you would be surprised to find what the engine builders have to say about these heads. They can check them inside and out, and rest assured, the heads will get their seal of approval. When we received our first set, the first thing we noticed was the overall appearance, and we found them to be the best looking heads we had seen in some time. They went on an engine the very next day, and we did extensive dyno testing. Intake installation was very good. Everything lined up well.
Here is a rundown on the hardware used in these heads and the assembly process.
Melling High Performance Dual Springs.
IMPORTANT NOTE, MUST READ!
We have noticed several sellers offering these heads with a one size fits all valve springs for dual use on hydraulic flat tappet and hydraulic roller cams.We are sure this is not the proper way to setup the heads.
If they have this one size fits all setup somewhere in the middle spring pressure values of what is required for a hyd. flat tappet and a hyd roller cam, then it would be too much for the hydr. flat tappet cam, and create a wear issue. Putting too much pressure on flat tappet cams is a sure way to kill the cam. If these middle of the road springs were used on a hyd. roller cam, then the spring pressure would be too low. Valve float and its damaging effects, along with a loss of performance, are sure to occur.
We use the correct spring for your setup and it is never the same on a hyd. flat tappet as it would be on a hyd. roller cam. As mentioned above, the spring requirements between a roller cam and flat tappet cam are dramatically different. Even the odd ball solid flat tappet cam has its own unique setup depending on the lift. The one size fits all hardware claims also to work on these cams. We know of several sellers offering this insane setup to unsuspecting buyers, and itâ€™s not the proper way to set up a set of heads. We would not even consider using a spring setup like this, and believe me, the simplicity of it is appealing.
The results produced by these heads will vary greatly depending on the type of setup you are running. The engine combos we have dynoed are what most people use for cam and intake selection, and the results are listed below. The engines dynoed were many 383's, and several 406 cid engines in the 10:1 to 11.2:1 compression range. All ran on pump gas.
The cams mentioned below are all hydraulic roller cams. The heads in this ad are setup for use with a hyd. flat tappet cam. This is just to give you an idea of the max. potential of these heads.
Please do understand that a cam is not included with the heads. This is just a guide to show what you may expect with a given combination when building a 383 engine using the ProMaxx heads.
Cam choice #1
PART # 186755-10 This is a hyd. roller cam for use with OE roller blocks only.
PART # 116755-10 This is a retro style hyd. roller cam for use with non roller blocks.
Valve lift with 1.5 Rockers: Intake .600/Exhaust .581
Duration @.050": Intake .251/Exhaust .255
This cam choice # 1 is very aggressive in the 383 Super Stroker engine. We have not offered this cam in the past with any of our Stage 2.0 383 engines. This is the same cam choice used in our 421/427 engines. The reason we decided to try it in our 383 Stage 2.2 was to see what the max potential was with our new ProMaxx cylinder heads. We pumped up the compression a bit with a flat top set of pistons, topped it off with a set of 1.6 rockers, and went with the Single plane Hurricane Plus intake, added the Super Sucker plate, and produced an amazing 570 horse power at 6550 rpm with 510 lb ft of torque at 5400 rpm.
Actually, the engine produced only 6 hp less at 6450. The horsepower numbers are very accurate. We performed the testing on our new Super Flo 902s dyno. The flowchart above certainly explains why we achieved such numbers. This setup is considered Pro street, and only usable in very lightweight cars with proper gearing, and a stall of 3200-3500. This is due to the cam size, 1.6 rockers, and intake choice. The compression ratio of approx. 10.7 was used, and cannot be run in very heavy vehicles with tall gearing. The drivability would be considered poor with this setup in a medium to heavy weight vehicles, (3400 lbs. or higher)
Those not familiar with Pro street setups should educate themselves on the subject before choosing a cam and intake such as this.
Buyers wanting decent street manners, explosive power off the line without the need for deep gearing, and with the need for a high rpm stall converter, need to stay away from this setup. Below are three more choices that will better suit your needs.
On the flip side, those that want the most powerful pump gas 383 available and enjoy the thrill of a pro street setup need look no further. This setup would please the Pro street minded to a very high degree. This cam beats the ground with no mercy. Give it the right stall, gearing, and a set of ET streets in a lightweight car, and you will have that sound and feel of power with acceleration unlike any 383 has ever achieved on pump gas considering the cost.
For those demanding top end power in the higher hp ranges and not wanting to sacrifice too much drivability, then I recommend building a 406 engine with the same cam setup. The 406 engine will move the torque band down much lower in the rpm range.
Cam choice #2
PART # 180345-10 This is a hyd. roller cam for use with OE roller blocks.
PART # 110345-10 This is a retro hyd. roller cam for use with non roller blocks.
Valve lift with 1.5 Rockers: Intake .565/Exhaust .580
Duration @.050": Intake .245/Exhaust .253
This cam is the most aggressive of the four choices listed. It will make its peak horse power at approx 6500 rpm. The idle is very radical. Power comes in around 3200 rpm.
We recommend a stall converter of around 2800-3200. Final gearing would need to be at 373 or numerically higher. A 373 final gear is most optimal with this cam, providing the car is reasonably light. This cam does make the most horse power but will trade off bottom end throttle response and low speed cruising in the low rpm range unless your car is setup in pro-street form. The idle sound with this cam is very erratic.
You would not be able to run an overdrive trans, power brakes, or air conditioning with this cam choice. Valve train life and reliability is reduced with this cam as compared to the other choices. This would only be a concern for those wanting to drive their vehicles on long trips or with frequent use. This cam choice puts your setup nearly into the Pro-Street league.
Drivability is fair at best with this cam, unless you have a very light car, with a decent final gear.
If your car is over 3400 lbs, we strongly advise against this cam, unless you have a final gear in the 4.10 range or numerically higher. If you're on the fence with this cam choice and the one below, then you may want to go with this cam and keep the rocker ratio at 1.5, or go with cam choice 2 and go with a 1.6 ratio. That would put you somewhere in the middle of cam choice 1 and 2, at least in respect to valve lift.
Below are our dyno results on one of our 383 engines with this cam choice with a single plane intake. Results will vary depending on intake choice. The horse power numbers will usually improve anywhere from 5-10 more than what the dyno results show after the rings have fully seated.
Official Dyno report on our 383 engine with cam choice #1, Pro Maxx heads, and a single plane intake.
Cam choice #3
PART # 180265-10 This is a hyd. roller cam for use in OE roller blocks.
PART # 110265-10 This is a retro hyd. roller cam for use in non-roller blocks.
Valve lift with 1.5 Rockers: Intake .530/Exhaust .545
Duration @.050": Intake .233/Exhaust .241
This cam choice (3) is the perfect all around setup for those wanting a decent bottom and mid range, while still generating excellent power at the top in a 383 engine. This engine will use the same pistons as the cam choice above, but you could have a bit less compression ratio and that would be fine. Horsepower rating would drop to approx 475 with this cam. This cam will make its peak power at approx. 5800 rpm. If your car is in the medium weight range or up to approx. 3,700 lbs, and youâ€™re wanting slightly better streetability, then this is a good cam choice. You still want to keep the final gear ratio at .323 or higher, but keeping the gear ratio on the tall side is more acceptable with this cam compared to the other choices mentioned above. You may choose 1.5 or 1.6 rockers with this cam, but we recommend the 1.5 rockers for better low end response.
This cam should be paired up with the dual plane Crosswind intake for excellent daily drivability. The single plane Hurricane can be used, but the dual plane will have much better bottom end and mid range response. You can also expect a longer valve train life with this cam compared to the larger cam choices # 1 or 2.
Cam choice #4
PART # 180245-10 This is a roller cam for use in OE roller blocks.
PART # 110245-10 This is a retro style roller cam for use in non-roller blocks.
Valve lift with 1.5 Rockers: Intake .500/Exhaust .510
Duration @.050": Intake .225/Exhaust .231
This cam choice (4) has a slightly lower lift and duration than the others offered above, and is highly recommended for use in heavy vehicles like full size sport trucks or very heavy cars. The low end response with this cam is very good. Horsepower rating would be approx 455 at 5,550 rpm. Compression ratio in a 383 could be as low as approx. 9.5:1 with this cam. Slightly higher would be recommended in a 350 build.
The rule of thumb with cam size is that the smaller the cam in a given application, the more improvement in low end response. One more benefit to the smaller cam is that the requirements for lower gearing and higher rpm stall converters is reduced. A final gear ratio of 310 would be acceptable with this cam. The bottom end power would be much better with this cam than with the other choices above. This would be the only choice for those wanting to run an overdrive transmission such as the 700R4 and cruising at around 2000 rpm in overdrive. A stall converter of 2,200 would be the minimum for this cam.
Do not choose the single plane Hurricane intake with this cam, as it would be totally impractical. Valve train life is extended greatly with this cam as compared to the other choices listed above, drivability is at its best. Low and mid throttle response is very strong. This cam choice will also produce the greatest amount of vacuum at idle compared to those listed above.
THE FOUR CAMS LISTED WILL COVER MOST NEEDS FOR ANY STREET ROD.
We have had a few customers who wanted to run their engine in a very heavy vehicle such as a 3/4 ton or 1 ton dually, 4x4 quad cab truck, or Chevy Suburban. These vehicles weigh approx. 6000 lbs or more. Even if you don't plan to do any towing or hauling of heavy items, none of the four cams listed would be suitable for this. We do have cams for such applications. We conducted a dyno test on a cam that would be ideal for such vehicles, Howards part number 180315-10.
Compression ratio could be as low as approx. 9.2:1 with this cam in a 383 build. This particular cam made 435 horsepower at 5350 rpm and produced 458 lb. feet of torque at 3500 rpm. This cam would be perfect in very heavy cars or trucks. Stock gearing would be possible and reliability would exceptional. We would consider this engine a true Torque Monster.
In-house dyno testing.
As of 9/15/2013, we completed installation of our brand new Super Flow 902S dyno. In the past, we outsourced our dyno work. In order to do the research and development we truly wanted, we made the $105,000 investment. Every aspect of our engines can now be monitored, calibrated, and tuned. More importantly, we can see what combos generate the best power, taking drivability into consideration.
We have built an engine that we refer to as our "house engine." Every week, we put this engine on our dyno to research different combos of head, cam, intake, carb, and setting changes to optimize the engine. The ProMaxx-200 heads have been tested many times on our house engine without fault. Similar testing was done with our NKB heads. We have torn the engine down once already and checked the ProMaxx heads thoroughly. We checked the valve guides for even the slightest wear, and all of the hardware. The ProMaxx heads were in perfect condition.
Head bolt washer recommendation.
Guide plate recommendation.
Stud Girdle recommendation.
If you are running full roller rockers, we recommend tall valve covers, and this can cause the oil that is pumped up into the top of the heads to not be deflected back down onto the valve springs, valve tips and roller rockers. The lack of oil on these parts can lead to not only a lack of lubrication but also to a lack of cooling on these parts. Heat transfers up the valve stem from the combustion chamber. This heat is very high in temp, and may cause serious damage to the valve guides, springs and roller rockers.
Most sellers do no testing whatsoever on the cylinder heads they sell. We do more than
just flow testing before we market a new style cylinder head.
Our choice of hardware also makes these heads stand out compared to others. Our testing has been very thorough, and to our knowledge, none of our competitors do this. We hope you value this extra effort. We do know that many dealers that purchase the heads in bare form are using less than desirable hardware, and they may not even have a true head builder doing the assembly or testing. Beware of sellers that offer little or no information on the hardware type and brand they use.
PROMAXX-200 64CC 200CC RUNNER SIZE STRAIGHT PLUG FOR SBC CHEVY ENGINES
Intake Valve Dia: 2.02â€
Intake Port volume: 200cc
Intake Port Dim: 2.300â€ x 1.250â€
Int Port Location: Stock
Intake Gasket: Felpro# 1206 fits perfectly. Should your intake drop to low, the 1266 will be required.
Exh Valve Dia.: 1.600â€
Exh Port volume: 70cc
Exhaust Port Dim: 1.356â€ x 1.420â€ w
Exh Port Location: Stock location & bolt pattern
Exhaust Gasket: Depends on what type exhaust your using. Try to match up the gasket to your headers.
Flow, Intake: See chart above.
Flow, Exhaust: See chart above.
Head Bolts: ARP 134-3601 See our other listings.
Head Studs: PC-2451-STUDS (12pt)
Manifold: Most any brand.
Milling: Min. Down to 58.5cc or 64.5 = .060â€ See info in this listing for details on this.
Pistons: Most 23Â°aftermarket pistons.
Push Rod length: 7.900 for hyd. flat tappet cams.
Push rod Guide Plate: We strongly recommend Dart flat guide plates. See our other listings for many accessories.
Retainers: Steel 10Â° Comp brand machined locks are used on all of our heads.
Spark Plug: Straight, .750â€ reach, gasket, Autolite 3923 or NGK 4544 is one step lower heat range.
Spring Pockets: 1.550â€ OD (.030â€ deeper max)
Springs: Melling 1.46 outer diameter, with an internal damper.
Valve Length: (+.100â€) for hyd. flat tappet cams.
Valve Stem Dia: .3415â€ - 11/32â€
Valve Train: STD SBC 3/8â€ or 7/16â€ stud mount
Valve Guides: 1/2â€ OD Int = Mag-bronze Exh = Phos-bronze (.002â€ press)
Valve Guide length: 1.950â€
Valve Guide clearance: .0014â€ - .002â€ (with our .3415 dia. valve stem)
Valve Guide Spacing: 1.890â€ moved .030â€ from stock
Valve Seats: Hardened Ductile Iron, .006â€ press
Valve Seat dim. Standard
Valve Seat angles: Int = 32Â° - 45Â° - 60Â° - 70Â° Exh = 37Â° - 45Â° - radius
Stud Girdle: Use any standard girdle. Our Gold Series stud girdle has a perfect fit.
Torque: Head Bolts = 65 ft/lb
Rocker Studs = 50-55 ft/lb
Manifold = 35 ft/lb
Block Use: Any SBC Iron or Aluminum
Weight: 60-62 lbs fully assembled pair.
A final note...
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