Once again I have to reach to you guys hoping to learn some more.
I am (still) working on my new engine and have reached the point where the old D0OE 351 W cylinder heads will be fixed. This means new valves, guides, springs etc.
The heads will also be "converted" to new ARP rocker arm studs and guide plates. We have all parts ready but I am having trouble determining how much to mill of the rocker arm pedestal. I have been searching the web and old articles and have seen various numbers fra 0.230" to 0.300". That seems like a big difference and one of the numbers is probably not correct...
Can anyone explain how I should determine the correct stud height for my setup. My first thought was to measure the OEM pressed in stud height (1,63") and match that with the new stud and guide plate. After milling the pedestal they would have the same "overall" height above the valve tip. Would that be the right way to go, or am I forgetting something????? E.g. does it matter that the new rocker arms are roller rockers?
I hope someone in here will guide me a little bit :grin2:
If it were me, unless there was a specific reason to keep those heads I think I would buy these FORD 289 302 347 NKB-190cc ALUMINUM HEADS 60cc STRAIGHT PLUG NKB-FORD-274 | eBay By the time you get done cleaning the castings, checking for cracks, valve guides, guide plates, springs, valves I think you'll have a lot more money spent then the NKB heads. Take a good look at the valve train parts, all Comp Cams and Erson. All well known brand name parts. Sure the heads are China but the parts and machine work is here.
I don't have a dog in the fight with these other then saying for the cost of a simple rebuild on stock heads, these look awfully tempting and they would make a lot more power. I don't know how they would compare to Trick Flow, AFR, Dart and so on, they're not even in the same price range so I wouldn't expect them to perform like them either, I don't think that is the point though.
I milled the rocker pedestals on my Australian 302C heads for a Clevor and .300" was the number for them so that may be where that dimension is coming from.
It is not a matter of cost! I know this is the odd way to go and I would get better performance from almost any other cylinder head....but I need to go with the old Ford parts.
Question is how I will make them work. It should be simple enough - but can't find the information I need.
That's why I was throwing that out into left field. I wasn't sure whether you wanted to keep the factory heads or just didn't think about the option. Definitely have a machine shop do it. Nothing wrong with fixing the stock heads up.
I would trust this to a machine shop. They do not charge a tremendous amount to mill these, if they are any good at all, every one of the stud bosses will be cut true and the threads will need to be opened up to at least 3/8ths. Don't the pedestals generally have 5/16 bolts? It is routine to do this sort of work when they are in there doing the seats and valves.
The other thing I would advise is to get a push rod length checker to make sure you are going to have the correct length push rods for this.
Aftermarket, aluminium, CNC ported heads are wonderful but they may also require work and can't be run right out of the box. I watched a machine shop that was working a brand new set of big block heads that had deformed intake seats. He had to re-cut every one of them because they had 9 thousandths run out. I never caught the manufacturer of the heads. Sometimes, the pressed in bronze guides are not right either. Even with after market aluminum heads, I would and have always bought heads bare and had a good machine shop that I trust set them up locally. While they are there, they can verify that the heads are to spec. I've also never had out of the box heads that would have come with the specific valve springs I needed to run either so. I hate this phrase but, they are what they are, it is what it is, sometimes it isn't what they advertise. All of this kind of throws a bit of water on the bargain aftermarket head thing. Hard to beat the performance though if they are done right. On the other hand, do you need 700 or 1000 horse heads on a 350 horse engine? Just saying that stock worked heads and aftermarket whiz bang heads each have their particular uses.
That's probably fine. Actually, the height is not critical, and whatever you choose will not effect valve train geometry in any way.
Do this: Get the studs. Measure one from the base of the hex to the top of the taper where the stud is straight. Measure the space between the stud boss and underside of the rocker on your assembled and installed head. If the existing space is equal or greater than the hex, no milling is required.
If you are using non-rail rockers, you will need guide plates. Include the thickness of the plate in your stud dimension.
If you are using rail rockers (mid-66 up) you don't need guide plates.
It is a fellow mustanger who will help me do the machining. He is very experienced with all the machines in his shop but just needed to know how much to "take off the pedestal".
I talked to another machine shop, but because it is in Denmark they don't know the american V8 engines too well. Give them a VW, BMW or a Volvo cylinder head and there would be no problems. They will be doing the valves, valve guides and hardened seats - and their work has a good reputation. @sportsroof69 are you sure that it would be enough to take off as little as the guide plates, approx .100"?
Hi again, and thanks everybody for your help! It is greatly appreciated.
I think I get the point now - mill away as little as needed. I will try to measure it to make sure that I get something that works. I found this picture which states that .230" should be fine....when measuring like 22GT explained (from the base of the nut to the stud becomes straight) it looks like it's very close to .230" and then maybe adding the thickness of the guide plate.
The engine is not a race engine under any specific regulations. I just like "the soul of the old Mustangs" and rarely use modern restomod parts unless I can hide them away 0 And I still think that the Ford engineers back in the day did a really good job while creating our Mustangs :nerd:
Notice that those instructions and diagram are specifically for the Cleveland heads.
In the chart it specifically says to mill .230" for 302 and 351W heads. Some screw-in studs have 3/8"-16 threads and some have 7/16"-24 threads. Be sure to drill and tap for the specific size studs you will be using.
Base Thread Length (in) 0.750 in. 0.710 in.
Base Thread Size 7/16-14 in. 7/16-14 in.
Effective Stud Length (in) 1.900 in. 1.895 in
Rocker Arm Nut Thread Length (in) 1.000 in. 1.000 in.
Rocker Arm Nut Thread Size 7/16-20 in. 3/8-24 in.
Z
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