Suggestions for new design Aluminum Mopar SB clean slate (kind of) cylinder heads
- Thread starter Johnny Mac
- Start date
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Open chamber Edelbrock heads on my 408 that have gone 5.98 so far and B1’s on my big block if I ever get it out of hibernation.
There would be no reason for a custom or non factory intake or headers. Not sure why you keep repeating that. For rocker gear, even if the head were to stick with chevy rockers offset intakes are availible up to .775 and in a shaft form. All this does not have to equal an indy and can come in at half the price.
B3422w5
Well-Known Member
your right. I missread that. Now that I see what is requested, it’s sounds like what’s needed is a nicely CNC’ed Chinese knockoff, of which there is no lack of options.
he could buy blanks and develope his own deal like Bloomer did. Those heads have made verifiable 650 horse already without offset.
So 500 or better isn’t asking for a bunch.
Would the head have to have a small block chevy stud spacing to accommodate the small block chevy offset rocker arm shaft setup? Did you have a specific setup in mind? Can all that still be compatible with the original small block chevy rocker arm and stud arrangement required by the original guidelines from Johnny. I'm guessing that you are thinking of this being an upgrade to the orginal head that is used along with a cnc upgrade or something like that where offset pushrods would be needed. Are you thinking raised port or not? If so is there a way to do that and still fit a la/ magnum head? More details on what you are thinking please.
I think it would have to have the chevy stud spacing to use the chevy shaft rocker system. Not sure how much difference there is between the magnum and chevy, if any. The valve spacing between the two engines are within a few thousands. There are a few different shaft systems I saw in a quick search ranging between .150 and .775 offset (the .775 being t&d). Yes I would propose raising the port, I believe Johnny mentioned raising the port 1/4 inch, this would put the port close to a w5 port floor location, and as long as the intake faces of the head were moved towards the center of the block the correct amount you would be able to use an la or magnum intake. The only caveat to that being you would have a larger gap at the front and back of the intake to be filled by a spacer. I posted a picture of an my la super victor intake sitting on my W5 heads on a 340 block earlier in the thread.
For a bigger port (cnc?) Head I would propose moving the pushrod out of the port to gain csa and volume, hopefully something around a 230cc which would require the offset rocker. To put it into a nutshell, something similar to a W5 without all the exotic/expensive race parts, would be the "cnc" offering. Standard pushrod, standard chevy stud rocker, the "basic/standard" head.
Seems reasonable. Maybe if the logistics were taken to the next level and presented to Johnny to show that this would not add to the cost of the " Base head" he might be interested. I can't speak for Johnny. If it has any chance somebody or somebodys may have to do a little more leg work.
MiradaMegaCab
Well-Known Member
I used that how to make some changes so I could use a factory ac water pump pulley. In addition, a parts store pump doesn't have a shoulder for the bearing, so it didn't need to be bored
If anyone decides to follow that path, I have the tool I made to press in the carbon seal available to borrow.
MiradaMegaCab
Well-Known Member
Professor Fate
Push the button, Max...
I don't know how this thread got onto water pumps, but...
There's an easier way around this, depending on your needs.
If you plan on running an electric fuel pump, this could be for you.
A 1990-91 (only) 318 (only) Dakota (only) water pump. It is a short-nosed water pump based on the upcoming Magnum pump, the only difference is it has a standard drive flange to mount V belt pulleys for standard rotation instead of the Magnum's reverse rotation.
The only catch is that you must use a Magnum-style timing chain cover with it, since the pump bolt pattern is slightly different than the LAs. The Magnum cover has no provision for a mechanical pump, but it retains a timing pad in the standard '70 and later LA location.
Dodge did this to fit the LA 318 into the clearance-challenged Dakota until the Magnum based engines became available in '92.
Maybe this'll work for you.
mopar65
Well-Known Member
My 91 V8 Dakota had a serpentine belt on it. But I am useing that water pump on my 360 magnum and driving it with a morose electric water pump drive
mopar65
Well-Known Member
Also my water pump is Reverse Rotation
Professor Fate
Push the button, Max...
1990, V belt drive.
Tough to get a pic of the pump itself with all the accessories on the front of the motor, but in this pic you can clearly see the pump fan, which is standard rotation.
All the same part numbers as a '91.
The serpentine drive on the '92 and later Magnums:
Maybe you got a real late '91 that may have gotten an early Magnum motor, but the LAs were V belt, standard rotation.
DionR
Well-Known Member
‘91 Dakota’s with the 5.2 got a serpentine belt drive. I’ve got one and have had to replace the tensioner twice now and they don’t make make a new one since it was a one year only deal. Different than the ‘92 and up Magnum setup. Real pain in the butt. So I know for a fact that they had a different setup than what you are showing.
D100’s, Dakota’s with the V6, vans, etc all got what you are showing. Dakota’s did not.
Professor Fate
Push the button, Max...
'90 318 TBI Dakota. What can I say.
Enough sidetracking, back to talking heads.
DionR
Well-Known Member
Far as I know, ‘91 was the first year for a V8 Dakota outside of the Shelby Dakota. Everything I’ve seen says the V8 was added at the same time as the new nose which was a ‘91+ deal.
mopar65
Well-Known Member
My 91 was a non magnum LA block. It had the factory 2 barrel TBI intake on it.
Can you please point me to DV's resume and track results? I'm sure he's had success on some level but outside of gear head circles he's not well known.
Rat Bastid
Dunamis Metron
The long answer is it depends on several things.
One being RPM. A cylinder head for say 408 inches at 7000 RPM may still be good for 340 inches at 8000.
It also depends on cam timing, which is also RPM dependent. If you are using SFT lifters you get screwed pretty easily because you can’t get enough lift before the lobe becomes too aggressive. You can get there with a roller lifter (BTDT) but its a bit harder to do with the roller.
As section increases the flow numbers go up more (let’s say as a percentage) at higher lifts than they do at lower lifts. As an example, I don’t care who you are or how you do it if you look at the same size intake valve (lets say 2.100 because that’s about the right size valve for a 4.04 inch bore) the increase in air flow at lower lifts (lets say lower lifts are .050-.350 for a cam in the .700 lift range) is increased much less than the air flow above that low lift. It is what it is. You can force more air past the valve at low lifts unless you put a blower or hair dryer on it.
The increase in flow really starts showing up at .19 L/D and up. Or close to that. So you need to open the valve more to use the increase in air flow or you’ve just pissed away a bunch of money. I will say the goal of any head designer/porter should be to get the flow to continue to increase all the way to 1.00 inch lift. I have done it a few times but a head with a conventional port location and tight pinch won’t do it. At least I can’t get one to do it. Even if you don’t use all that lift, the flow curve increasing is a clue that the port is working.
At any rate, once you increase the cross section and get more flow and you need to add lift. You quickly learn that even with a roller lobe you can get to the point of the lobe being so aggressive that you start needed Comp Eliminator style spring maintenance.
Not good for a bracket racer or even a heads up car if you don’t need it.
I learned this the hard way on my W5 heads. I developed the ports to net .800 lift. When I finally got the ports in shape to do it, the best I could do was a lobe that netted me .736 lift. And that lobe would need springs every 150-175 runs, depending on what RPM I shifted at. Had I wanted to cut that down to 100-120 runs, I could have netted .775 but the math said it wasn’t worth it. To actually net .800 lift I would have been in 40-50 run area and I didn’t have the budget for that.
Like I said, the best answer is the short answer and that is it depends.
Just because a head is “big” doesn’t make it a bad head and just because a head is ”small” doesn’t make it a good head.
These engines are so valve and induction limited it’s crazy. With a correctly sized port you could run far less seat to seat timing with much higher lifts, make more power and go quicker and faster.
All of this is nonsense to the bracket racer, but in actual drag racing it matters. Unless we are talking fast bracket racing like Top Dragster or Top Sportsman. Those guys are far less bracket racers and are closer to heads up cars.
Johnny has stated that these heads would be made with the intention of being used on 500 and less HP engines as laid out in his list of four criteria on post 1. Hypothetically, If you used 400hp as the low end and 500hp as the high end then 450hp could be the target for optimum port size. A little big for 400 hp and a little small for 500hp. This would be the base head used on his crate engines and available to the public to buy for their own use.
If you were given the task of designing the ports, combustion chamber, hardware and etc. To meet the criteria in the four points that Johnny has laid out for approximately 450 hp. how would you design it? What valve size, chamber size and shape, port shape and cross sectional size and etc. would you use?
The next part is the more challenging part. What would you incorporate into the original design that would allow it to be modified to be used in an engine making more than the 450 horsepower it is optimally designed for? Without adding to the cost of the original casting. Or maybe the extra cost could be justified in the end. It's not for me to decide. Let's call it a stage 2 version for now. Here are examples of what a stage 2 head might include. CNC porting, Increased valve size, increased valve spring size. retainer to guide clearance, better rocker setup, and etc. You pick the hp level and rpm limitation that would be optimal for the extra cost of a stage 2 version. Maybe it could compete with the W series heads or maybe that's not possible.
Peak Hp is only one aspect, how efficiently each powerstroke is between **** and recovery points the flatter the power curve the faster the acceleration. One way to measure is lbs-ft per cid 2 408 making 450 hp but one making 1.15 lbs-ft per cid and the other 1.3 lbs-ft per cid the 1.3 lbs-ft will make power at a lower rpm being more efficient per powerstroke and will have a flatter higher average overall power curve. Plus heads that choke the engine power falls off rapidity after peak needed to shift sooner and drop further down in rpm per shift probably leaving you further outside the main powerband top 10% of hp slowing down acceleration.
Using horsepower to determine port size might not be be the most accurate way to determine port size but it's the only information provided so far. I think it will work for starters until more details are known about the crate motors they will be used on. Comprises will have to be made. What is optimal for one version of crate motor offered by Blueprint may not be optimum for another version.
All that said the process to think about how it can be made so that it could be tailored for individual engines and at the same time meet the requirements Johnny has laid out for his engines can still happen.
All that said the process to think about how it can be made so that it could be tailored for individual engines and at the same time meet the requirements Johnny has laid out for his engines can still happen.
He clearly stated parameters to work within, however, unless Blueprint comes up with something different than others offer, it might not be worth all the trouble, EXCEPT to simply supply THEMSELVES with heads for their own engines......and that'd be ok, too. I welcome anything new on the Mopar front, it would just be nice if someone offered something a bit different than what is already available.
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