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).
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.
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.
PBM/Erson Competition Series Valves.
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.
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.
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.