Skip White Performance - We have the best prices you will ever find for aluminum heads, rotating assemblies and strokers
Skip White Performance
1910 Brookside Lane
Kingsport, TN 37660

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DART PRO ONE SERIES ALUMINUM HEADS 345cc REC. PORT ASSEMBLED DART BBC-DART-274

Available

$2,395.00



Product Information

UPC352416954950
Product TypeShipped Product
Shipping Cost $48.50
Number of reviews 0

DART PRO-ONE 345cc FULLY ASSEMBLED HEADS. CNC'D COMBUSTION CHAMBERS.

FOR USE WITH HYDRAULIC ROLLER CAMS UP TO 620 LIFT.

122cc COMBUSTION CHAMBERS 345cc runners.

This sale is for a set of heads (2 heads).

DART 345CC BUILT HEADS SONY SHOT photo 3666673a-ad6f-4dd8-b73b-fceb2891392a.jpg

We also have these heads set up for use with hyd. flat tappet cams. See our other listings.

Solid roller setups also available.

Pictured below is the CNC'D combustion chambers.

The cnc'd combustion chambers were done for us by Dart. We have found this feature to increase the HP numbers by approx. 10-15.

To be clear on this, the runners are not cnc'd, just the combustion chambers.

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The Dart Pro One 345 bbc rectangular port heads are perfect for 454, 496, 540 and 572 street/strip engines.

We have complete top end hardware kits available for these 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-1017-1275, or any TEK kit that has the 1275 part number in it. The first number is the type of head gaskets, and we have several different head gaskets that will work with the Dart 345cc heads. The 1275 is the intake gasket part number, and that is mandatory for use with these heads.

In the lower section of this ad, you will find valuable information on how these heads perform when used with various engine sizes and cam combinations in street rod form. Please read the complete ad before purchasing.

Fully assembled with premium PBM competition grade valves, Melling springs, Comp retainers, Comp viton valve seals, Comp spring ID locators, Comp 10 degree locks. The hardware setup in these heads is for use with hydraulic roller cams. Below is a detailed breakdown of the hardware used in these heads. We do offer these heads set up for all types of cams. See our other listings.

Valve size 2.300 and 1.88. These heads have the correct seat diameter to allow use of these valves.

We do our own assembly on our heads. See details below about our hardware and assembly procedure.


We also offer variations of these heads for use with all types of cams. Be sure of what type cam you plan to run before purchasing. Read the ad completely before purchasing.


The horsepower gain from the weight reduction of aluminum heads alone is noticeable, not to mention the fact that aluminum heads will allow you to run a bit more compression without the risk of detonation. The benefits are many to running aluminum heads. The most expensive cars in the world all run them. There are no drawbacks!

Tech support is available. We are confident that we offer the best advice in the business.

We also offer these heads in bare form, as many customers have selected a machine shop of their choice, as well as their own hardware. We hope you will check out our other listings for the many other items we have available.

Here is a rundown on the hardware used in the Dart 345cc heads and the assembly process.


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PBM/Erson Competition Series Valves.

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The retail cost at most High Performance stores on the PBM Competition valves is $239

Pictured below on the left is the PBM competition valve, and the other pic. is of our conventional style valve. It was difficult to show the back-cut feature in the picture, but note that the valve on the left has a third radius cut.

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We are now using the Competition Series PBM valves in all of our engines. These are considered a high end valve. These valves have an undercut and backcut feature.

The backcut feature reduces valve weight by an average of 12.5 grams per valve. This weight reduction of approx. 220 grams off the complete set of valves has a monumental effect on acceleration, deceleration, and valve train life. It may be difficult to understand how this works, but rest assured, this is a huge reduction. The valve spring compression and rebound action will remain stable for a much longer time running lighter weight valves, as well as reducing valve float.

The backcut feature is not be mistaken for undercut. These valves have both features. Backcutting is an additional radius, but located on the head of the valve to increase the flow numbers and reduce valve weight. The flow increase is approx. 3-6 points on the flow bench, and possibly more, depending on the initial flow rate of the heads.

According to one of our machinists who built Winston Cup engines for 15 years, the exhaust valves had an additional radius cut on the outermost edge that allowed a better escape of the exhaust gas. This cut on the exhaust valve is in addition to the back-cut feature. The competition series are made from a much higher temp alloy than most other stainless valves. There are at least three levels of stainless valves on the market, excluding those used in very high level racing such as pro-mod. The PBM competition series is compared to the highest level of those three. As a final note, backcutting a set of valves is said to improve flow in the low lift area, and this is most desirable on street rods.

Below is a copy of one or more of our invoices from Engine Parts Warehouse showing a recent large order for our PBM valves. We have removed the price and our account number for privacy reasons. This is the best way we can prove to our customers that the valves we use in our cylinder heads are genuine PBM products.

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Melling High Performance Dual Springs.

Our Melling springs are 1.46 diameter, with an inner spring and internal damper. Others are using springs that are much smaller in diameter. Smaller diameter springs may be in the correct spring pressure zone, but they usually have a shorter life. Melling springs are made in the USA. All of our engines using the NKB heads use these springs. Spring failures are near non-existent.

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Comp 10 degree machined valve locks.

We use only Comp Super 10 degree machined locks. Our head builder noticed the low grade locks on the market fit more loosely than he felt they should, not to mention the possibility that they were made of inferior metal. He envisioned the engine being much more prone to dropping a valve at high rpm. Using these locks, we have yet to have an engine drop a valve due to a valve lock failure.

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Comp Cams retainers # 75740-16 and Comp Cams ID locators Part number: 4771-16

Our Comp Cams retainers # 75740-16 and Comp ID locators # VTH-4771-16 are made from 4130 chromoly steel. These retainers have a perfect fit with the Comp valve locks. We have used these on all of our engines for many years, and have had zero failures.

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We purchase most of our valve train hardware in bulk for our engine program. Below is a copy of one of our invoices from Comp Cams showing several of our rather large purchases of valve train hardware. We have removed the price and our account number for privacy reasons. This is the best way we can prove to our customers that the valve train products we use and sell are genuine Comp Cams products.

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Assembly Procedure

We hone all of the bronze valve guides with a ball berry flex hone to establish not only perfect clearance, but also a semi cross hatch finish for oil retention. We finish off with a natural bristle brush. The heads are then placed in our parts washer and cleaned with high pressure hot water, then pressure dried. Before installing the valves, we apply a heavy coat of engine assembly lube to the valve stems. The coating on the valve stems is essential to protect the bronze guides from gaulding on initial startup.

Our next step is to set the spring pressure to a predetermined pressure using a spring height checking device, most suitable for street rod use. The springs we are using allow for a near perfect seat to nose ratio. Be warned that some sellers of aftermarket heads may not be checking the installed height when assembling the heads, and may not be setting them up to the correct pressures. We have a full scale machine shop with several very knowledgeable engine builders that know and fully understand how to properly assemble a set of heads. Combine the possibility of poor assembly methods with incorrect or low grade hardware, and it is easy to see how failures can result.

Guide plate recommendation.

We strongly recommend the use of the Dart adjustable guide plates with these heads, or with any BBC aluminum heads for that matter. These guide plates will allow better rocker tip alignment due to the fact they are fully adjustable. We use them on every set of BBC heads we install on our engines, including the Dart Platinum Pro-1's, and AFR heads. The rocker tip may end up offset to one side more than is acceptable when using fixed guide plates, and the Dart adjustable guide plates allow a decent amount of correction. The variances in stud position to valve guide alignment vary on all brands of heads. The rockers could also contribute to this issue, as the trunnion or rocker body could have variance. By having proper rocker tip alignment, you are distributing the pressure on the valve tip evenly. This not only reduces uneven valve tip wear, but also prevents undue stress on the valve guides in the heads. The part number for these guide plates is BBC-ADJ-GP. See our other listings for these items.

Pushrod recommendation.

Do not use stock GM pushrods with these heads.

The spring pressures on aftermarket heads are somewhat higher than on OE heads. Combine this with the larger lift and duration cams often used, and stock pushrods may flex or permanently bend. They will most likely be the wrong length. The stock pushrods are usually made from a mild 1810 steel that has been heat treated. Under high rpm, they will usually flex and cause a loss of lift, resulting in a power loss. The engine will usually run erratically when pushrods are flexing. The Spintron valve train dyno proves that inadequate pushrods will flex to a great degree as engine rpm increases.

Some GM pushrods have a welded ball on them, and they stand a greater chance of breaking off with the use of larger than stock cams and increased spring pressure. We offer high quality USA made, Howards brand pushrods made from 4310 chromoly. They are superior to any stock pushrod. Our prices on them are the best you will find.

You will see many low cost pushrods on the market, but these are totally unsuitable for use with these heads for the many reasons mentioned above, and they are not guide plate compatible. These pushrods will cause problems when used on a high performance setup.

IMPORTANT NOTE CONCERNING ROCKER ARM STUDS.

If you have been a regular shopper with us, you will have noticed we do offer some knock-off products that are made off-shore. We do also sell many products made in the USA. We have always been very particular as to the quality and workmanship of such products, while considering the cost. We scrutinize our products very carefully and refuse to sell products that simply don't meet our standards. We have now eliminated another of the low cost knock-off products from our line. The low cost imported rocker arm studs have shown numerous problems unlike those in the past. We have looked at several others on the market, and still find many issues with them that are not acceptable.

Many of the studs had run-out in the shaft of up to an eighth of an inch. This caused major problems with rocker alignment, and depending where the position was when the stud tightened up, would determine the direction of the rocker misalignment. If the warped stud was facing toward or opposite the valve, then the roller tip would would not be centered to the valve tip. This would then create a loss of lift and cause increased wear on the valve tip.

If the warped stud tightened up in a side to side position, then this would allow the rocker tip to be cocked on the valve tip. This would then side load the valve tip with undue pressure, creating a serious wear problem on the side of the valve tip and create excessive wear on the valve guides in the heads. This also side loaded the rocker trunnion and front roller, creating an excessive wear issue in the roller rockers.

We also found a difference in the tread pitch and depth compared to the ARP studs. The rocker studs in an engine are under a tremendous upwards pull and improper thread design may cause the studs to pull out of the head. The ARP studs screw into the heads with a very precise fit and feel.

After thoroughly comparing the ARP studs and several off shore models, I am convinced that we will never offer the off shore studs again, regardless of the price difference. They were never as bad in the past as what we're seeing now. This run-out was most likely caused by improper heat treating methods.

We are aware of only one other rocker arm stud besides ARP on the market of decent quality, and that's from the GM Performance division, and it's fair to say they are most likely supplied to GM by ARP under private label.

We have rejected many products that are outright junk and would cause serious issues in your engine only to see other sellers offering those same exact products. It's all about learning where to draw the line.

The correct ARP rocker stud part number to use with these heads is #100-7101. See our other listings for these parts.

Studs and guide plates are NOT included. Other sellers may include these items but rest assured, they are usually not suitable for these heads. We use nothing but the Dart adjustable guide plates and ARP rocker studs when we build an engine using these heads, as they allow for perfect alignment of your rockers. See our other listings for a full selection of accessories.

We are glad to offer many great low cost items, as well as the high end products, but will always give careful consideration to quality, functionality, and overall value.

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 it'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.

SPEC INFO AND RECOMMENDED ACCESSORIES FOR FOR THESE HEADS.

Intake Gasket: Felpro 1275 For rectangular port heads. These intake gaskets have a glove like fit on the Dart 345 heads.

Intake Port volume: 345cc

Intake Port Dim:

Int Port Location: Stock

Intake Valve Dia.: 2.300"

Exh Valve Dia.: 1.880"

Exhaust Port Dim:

Exh Port Location: Raised

Exhaust Gasket: Depends on what type exhaust you're using. Best to try and match up the gasket to your header or exhaust manifold

Head Gasket: Felpro 1017-1 for Mark IV & VI blocks, or our PC-5211 MLS head gaskets.

Head bolts: BBC-50 Head bolts, or ARP 135-3607 Head bolts or our BBC-75 Head stud kits.

Manifold: Most any oval or rectangular port style intake will work.

Milling: Max. .060 Scroll down to see info in this listing for details on this.

Pistons: Most stock or aftermarket pistons. Our Wiseco pistons combine perfectly with these heads.

Push Rod length: 8.850" intake side, 7.800" exhaust side, when running .300 tall tie bar lifters. See our other listings for pushrods.

Push rod Guide Plate: We strongly recommend Dart adjustable guide plates. Not included. # BBC-ADJ-GP. See our other listings

Rocker Arm studs. ARP 100-7101 Do not use off-shore rocker arm studs. ARP only. Not included. See our other listings.

Retainers: Steel 10° Comp brand machined locks are used on all of our heads.

Spark Plug: Straight, .750" reach, gasket, Autolite 3923 or NGK 4554 for one step lower heat range. See our other listings for these.



A final note,

Our user id is: skipwhite, and our store name is whiteperformance1. You may have noticed other sellers using a similar name offering similar products. These other sellers have capitalized on our name as we see it, and many customers searching for us will inadvertently find them, thinking we are one in the same company. There is only one "Skip White." We are the original premier seller under this name since approximately 2002. We have no other names, nor are we associated with any other company regardless of the similarity in the name or location. Our official company name is Skip White Performance.

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