I purchase a used set of D1AE 4V quenched chamber heads. They've been rebuilt with what looks like Stainless Steel intakes (because there is no rust on the valve stem tip, see picture) and steel exhausts have a mild rust on the stem tip, all the valves are like this. 

The one concern I have is the exhaust valves, they look to be welded due heat discoloration where the head and stem meet and could have been welded? Can someone confirm? Just want to make sure they are one piece valves.  My thought is if they are a two piece welded valve I will/should replace them?

Also the spring seats have been cut to accept two springs and a damper, so triple springs. I don't know what they are rated at.  I'd like to keep the springs, and retainers.  Is it advisable to get new keepers?

 Also I will change out the seals....the ones installed are Comp Cam Valve Seals, they are supposed to be used with double springs from what I've read, while Vinton seals are supposed to be used with triple springs.  Also I don't believe the Vinton's will fit due to guide diameter needed at .530, the Comp Cam seals are listed at .50 so I assume the guide had to be cut down.  Therefore, I may be forced to stay with the Comp Cams seals which then may force me to go with double valve springs, and not sure I can do that since the spring seats in the head have been machined flat?

My goal is to get my motor back in the car, have a dependable driver I can take most anywhere, including longer trips. I have a 72L, flat top pistons, may go with a little hotter then stock cam grind with hydraulic flat tappet lifters.

Steps: #1, decide which parts I keep and which I toss and replace. #2, If I keep these valves have the valves and seats ground, #3, have guides checked, #4, have the head gasket surfaces cleaned up, #5 decided on valve rockers. 

Thanks in advance for suggestions.

exhaust valvevalve stems with single grooveValve stemsComp Cams valve sealsValve heads


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Original Post

I can't help you on the valves, but do you have the pedestals cut for stud mounted rocker arms?  Are they 3/8" or 7/16" studs?

If you are considering doing that (modifying the posts for studs), here is the info on cutting the pedestals down...

Then again - there are methods that don't require machining the slotted pedestal..



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It would be best to replace everything with known  items.

Triple springs suggest very high rpm roller lifters. You would only need them for something like an 8,000 rpm engine with solid rollers. Those do not appear to be stainless valves to me.

You need to be concerned with your pushrods with those springs and you could be putting yourself into needing a rebuild every 500 miles or so using that much pressure. If that's the type of engine that you want, then go for it.


7/16", screw in rocker arm studs are what you want and I would say that neither the intakes or exhausts are what the current configuration of high performance stainless valves look like. They look like TRW replacement valves. The entire mix of specs is screwy.

Most now are going to have some form of cutback stems in the valve pocket area and have indication of full machining on the tulip portion of the valve.

Many manufacturers stamp or lazer cut part numbers into the stems near the tips. Look there for numbers.


If it were me, I'd replace the entire valve train and install new guides as well.

It would be advisable to take them to a shop that is familiar with high performance Fords.

Also, using triple springs with bolt down rocker arms seems a conflict of terms. That's only a 5/16" bolt and the rocker arm fulcrums are cast. That combination is just a disaster waiting to happen. Mahem is hiding in the wings.

Doug, thanks  for the input. I agree with a number of your points. I was hoping I could replace just the exhaust valves, and makes sense to toss the springs.  I had planned on upgrading the rocker arms to something with a roller tip and possible a bearing falcrum and makes sense to go with a 7/16 bolt. I'm surprised they machined the spring seats and didn't put in rocker arm studs.

Hi Doug -

Anyway - I took a quick look at these - what controls the cutting depth? 

I guess their purpose is different than a "pedestal mill", but... are they primarily for spot facing, or flattening out the area for the spring seats, and depth control isn't supremely critical?

Thanks -



You control the depth of the cut. If you want to be accurate to .001" then do it on a drill press or better yet a mill but I can tell you that the machining from Ford on cylinder heads isn't terribly accurate to begin with.

Don't go trying to measure angles of the rocker arm studs using the bolt holes as a reference. You will be very upset in the findings. Even the center lines of the rocker arm bolt holes are not right on center.

It COULD be why that particular set of heads were left with the bolt down pedestals but had spring height work. Certainly the PC stem seals are the right thing to do.


I never tried to put bigger valves in a 351-C head but have on Windsor heads. The valve guides are so off on them that it's typical that on the same head you can get a 2.02 in two of the combustion chambers but only a 1.94 in the other two.

These things are just production heads designed for lo-po applications and in most cases would never go over 5,000 rpms anyway.

I would expect Cleveland guides to be as inaccurately placed as the Windsors although I have never measured them so can't speak to the commonness of the occurrences?



Even on my factory Boss heads with which I had nothing to do with the cuts, the studs hardly line up perfectly.

As long as you stay with basically with the cutter just kissing the pedestal bolt height, they work fine.


In addition to the cutter, you need a guide so by the time you total up the parts you would be better off paying the shop $150 to $200 to do it for you anyway.

On a mill in the shop, all you are going to do is put straight edges on the pedestals as reference points and use a square to get the cut "plumb".

The cast pedestals didn't need to be highly accurate because of the hydraulic lifters. Solids with guide plates is a little different.


My converted heads worked as well as the factory Boss heads did. So my procedure was accurate enough for a .600 lift  solid lifter cam, with guideplates, 7/16" studs and roller rocker arms.

I know from using Jessel shaft mounted rocker arms that you had better be right on it because there is no play in their operation at all. Although typically you have to shim the rocker arm seats for height and they usually come with an assortment of various thickness hardened shims as a result. In other words the manufacturer is aware of the heads being not machined accurately enough.

In fact you might NEED aftermarket heads to use with those? So far for me, the aftermarket heads have been right on the numbers but you really can't tell until you go assemble everything and check. You can't mess around with them at all. Your first indication probably would be to immediately bend all of the push rods at start up?




Doug, I found valves at SI Valves (someone here recommended them). Seems like Cleveland valves are getting tougher to find. A lot of places show them out of stock. The ones at SI Valves won't be in until late December. They are Server Duty racing stainless once piece for $160, very reasonable. As a side note as others have mentioned BBC valves will work in a 4V head.


I think I'll go with Scorpion Rockers with a 7/16 bolt or stud. Their rockers seem to be pretty stout and will handle up to 950 lbs of spring pressure (double of what I'll be running I believe), also they give a lifetime warranty.  So now I just need to decide on a cam specs, springs, and push rods . I've been looking at the Lunati Voodoo cams. I believe they also sell lifters with it, so I'll get their best surface finish as Mr. Pence recommends. Thanks for the suggestions and experience Doug!  I really appreciate the help!

Are you going to take the heads and valves to a shop to get a valve job or are you going to attempt a homebrew lap job?

I am stewing over whether to have mine machined or just stash them in the attic and buy aluminum replacements.  I will have aluminum eventually, but I'd like to know what the car was like with the original heads.  I just don't know how bad I want to know that.

Perry I wish I had the tools at home to do my own valve grind. When I was in high school I took two years of diesel mechanics as a transfer student to the local college...learned a ton. Got to use their equipment and the teacher let us build a few race engines with three angle valve grinds. Unfortunately I will have to send the heads out for a valve grind, and to have the heads surfaced to clean up the mating surface. I'll also have the guides checked. 

I think you would be happy with the stock heads. I know another Pantera owner with a 408 with 4V heads that had some "minor pocket porting" done, he dyno'd it and is making 590 hp at 6200 rpm. If they will flow that well for a 408, they should do great for a 351+. 

tomsealbeach posted:

The one concern I have is the exhaust valves, they look to be welded due heat discoloration where the head and stem meet and could have been welded? Can someone confirm? Just want to make sure they are one piece valves.  My thought is if they are a two piece welded valve I will/should replace them?

A good quality two piece valve is fine.

The stock valves fail because the heads are brittle … not because they are made from two pieces. When valves fail they crack and separate from the stem below the weld, not at the weld. Most valves in the world are made from two pieces, but they don't fail. 

A possible source for you would be Precision in Nevada, 702-263-6300 . They make the bronze guides that you see in seemingly all of the aftermarket aluminum heads.

They make severe duty stainless valves which are used by just about everyone (Edelbrock, AFR...pick your manufacturer, etc).

The only issue is that you need to establish a business account with them. That only takes a minimum order of $100.

These are the components that you want. Everyone just repackages their products and marks up the prices. All are made in the USA.

I don't have their web page link.


I have my own "valve job" equipment since there aren't many local shops that will do a real three angle valve cut. Some race teams go more angles then that but on a street car that is huge overkill.

Cleveland heads really respond well to a high quality valve job. They are worth the effort. Most aftermarket heads already have them and are using Precision's components. My AFR's came with a 5 angle out of the box and CNC ported.

Building your own can be fun but it is time consuming and if you had to pay someone to do it you would be triple the cost of buying an aftermarket head already to bolt on.


The Ford iron head pockets to me are controversial. They have cast in "reduction rings" just under the valves. Those were put in to increase throttle response on street cars like the Boss 302.

If you look at the cross section of the port in the Boss 302 competition booklet, "Off Highway" , I think that you will see that they recommended removing that ring for competition.

On a 300hp 351c on the street, especially with an automatic transmissioned car that is used as a commuter also, leave them in. In order to get the big numbered horse powered engines, you need to take them out. Then the heads start to flow ridiculously big numbers but you need to match them with a camshaft and that doesn't match rush hour bumper to bumper traffic characteristics at all.

It depends on what you want out of the car? I would think that there aren't many Panteras left that need to be worried about being used constantly in that type of traffic? The original equipment engine would still fit that bill.


The 351 Cleveland is pretty easy to get 500hp out of even with the original (worked) heads and in a Pantera with the short exhausts, make sound like a Formula 1 car bleeping the throttle.

It MIGHT be the safest bet to have an original set of iron street heads that you keep on the shelf and a nice set of aluminum high port heads to make this thing scream, and scream they do with relatively  little effort.

Stock 4V Exhaust Seats vs. Hardened Seats?

The shop I found who is likely the one to do my 4V head machine work (valve grind, clean the head surfaces) on my heads is recommending replacing the OE Exhaust Valve Seats with hardened seats. What is the consensus? Is this needed?

This gentleman has a lot of experience racing 351C's in drag racing so is well versed on them. He says due to the unleaded fuel we run, he recommends this?  

tomsealbeach posted:

Stock 4V Exhaust Seats vs. Hardened Seats?

The shop I found who is likely the one to do my 4V head machine work (valve grind, clean the head surfaces) on my heads is recommending replacing the OE Exhaust Valve Seats with hardened seats. What is the consensus? Is this needed?

This gentleman has a lot of experience racing 351C's in drag racing so is well versed on them. He says due to the unleaded fuel we run, he recommends this?  

Hardened seats on iron Ford heads are unnecessary and actually redundant.

Here is why.


Ford uses a harder cast iron in there castings then GM does. It's called nodular iron.

Originally insertable valve seats were invented for use with aluminum heads since you really can't keep an aluminum valve seat functioning for very long if at all.

One of the compromises with using an insurtable seat in any head is that the area you are going to install them in has to be thick enough to seat the insertable ring without weakening the valve pockets and the combustion chamber.

Some can't before eventually cracking down into one of the port walls.

The original Ford iron 351c heads seem thick enough if the cast in "velocity" ring has not been removed by "porting" the pocket opening.

That ring kind of reinforces the pocket walls.


The material used in the insertable valve seat (it's an unfinished ring) is cast iron. It likely will be the same as in most if not all of the current aluminum aftermarket heads.

It is actually softer then the original nodular iron in the Ford head. The original Ford iron seat is BETTER. Therefore you should only use them to repair an existing seat to save the head.


The ONLY exception to the cast iron seats that I ever saw were the stellite seats that Ford used in the aluminum 427 heads. Those were never intended to have street use and were used just for the race cars like the GT40 where ultimate dependability was done at a "cost is no object" basis.

You can't break those things with a jack hammer but the trade off is they are terribly difficult to cut the seats on.

You will go through an entire set of stones and will be going nuts resurfacing the stones.


SO, any knowledgeable engine builder is going to know this. So if he is trying to sell you a set of insertable valve seats, he's trying to just make you spend more money with him because he needs it.

Save your money. You don't need them UNLESS the existing ones have been cut so many times that the valves sit too deep or if you have a seat damaged to the point where it can no longer be cut properly.


Great info Doug!  Thank you for all the details!

I'm not sure if the existing seats are good or bad, I need to drop them off to get the job started. I have to assume they're ok because these heads can go a lot of miles. Although I have no idea how many miles on these heads.  I will post my results.

Thanks very much!

Look at the valve seats as they are. Do you see smooth polished like patterns with no cracks or chunks missing from them?

Drop the valves into the heads. The edge of the valves should be sitting up above  the surface of the combustion chamber. If you have feeler gauges, try and measure how much they are sticking up.

You really only have an issue if they are close to being even with the surface of the combustion chamber. There should be at least something like .030 or .040" of an edge, i.e., the valve surface being higher then the combustion surface.

If they are even or close, then  there is a case for valve seat inserts.

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