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Ford A460 head differences over the years

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13K views 106 replies 16 participants last post by  600" BBF  
S
#1 ·
I have two sets of the OLD B460 small port heads, I thought I might use them as welding cores
for a more radical port head.
On the evolution of these heads, have the valve locations been changed in different head versions ?
Valve to piston pierce points ?
Spark plug location ? Rocker mounting location ?
I ask because the currently available Trik Flow 360 heads have 2.400 / 1.880 valves which I don't
think will fit in my old heads. I suspect the seats/guides have been moved a bit.
Thanks for any history lessons you can school me on !
 
6
#8 · (Edited)
My first set of A heads were purchased in '91. I could have gotten a set B heads at the time. Same head and architecture with a much smaller intake port.

(something Paul Kane wrote about them on the 460Ford.com site

Paul Kane


If you have the B460 Truck heads, they are very much like the TFS/Motorsport A460 heads except that the B460 heads have a much smaller intake runner (the intake bowls are the same between the two heads in question). They were essentially made for the truck pullers that were often limited to a 470 & Under class, although they can be very useful on other small displacement engines, of course. About 500 were cast (250 pair). In short, the intake port is smaller by way of the intake floor being filled up (relative to the A460 runner), and yes it may be fully opened up to that of the A460 runner size. But please, if you want the A460 ports then buy the A460 heads; there are not as many B460 heads out there
 
#6 ·
I did an old set of Trick Flow A460 heads which, IIRC, became the Ford A460. I did 2.40/1.880 and they were .500" off the seat before they touched. For shaft rockers, T&D had all individual stands for intakes and exhaust and the old trick was to weld tie bars between them tying them all together but I got curious and in the end, I was able to use current A460 one piece intake
stands which had the correct spacing and angles, just had to move the rocker a little (closer or further form the valve...don't remember). T&D made some new stands. The ex stands proved to be a little more of a challenge l but in the end we were able to run the one piece intake and individual ex rocker stands that all bolted together, instead of welding all the individuals together. Turned out to be a MUCH better valve train. So to answer the question, yes, it seems something has slightly changed form the old Trick Flow A460's to the new as far as valve arrangement.
These flowed right at 500cfm with the 2.40 valve.
I know nothing about the B460's other than to say I would guess they would use all the same dimensions as the A head for ease/cost of machining.

Image


Image
 
#29 ·
Steve.k said:
The sr71 has about a 1” longer runner the p51.
Click to expand...
Haven't read fully up on the differences between the P51(D) and the SR71... The SR71's claim to fame is it's SHORTER intake port. It moves the valve towards the intake manifold, away from the cylinder wall. This opens up a lot of flow into the cylinder by not being limited by the bore. Of course, the intake opening is also raised.

Does the P51 also have the shorter intake runner? ...or do you have those backwards in your above post?
 
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#34 ·
Steve.k said:
View attachment 550098 Im wrong its 1/2 longer on sr71. Go to 6:50 mark of video if you dont wanna watch all of it.
Click to expand...
Since the intake port is raised, the head had to be made longer in order to fit a standard dimension intake manifold.
The point I was making, is the port itself is shortened COMPARED TO STOCK in relation to valve location. This was done to unshoud the valve away from the cylinder wall. If the P51D has the valve in the same location as the SR71, then yes... the D head will be a little shorter if it doesn't have the raised intake port.

Compare the deck of a stock 460 head and the SR71. You'll see the intake valve placement is pulled way back towards the intake compared to the factory location.

Image
 
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#37 ·
I could also be mistaken on the amounts. I'm sure I remember him saying the valve was moved back compared to stock to unshroud it from the cylinder wall. I believe the P51 is also moved. I'm having trouble finding out exactly how much. I may have stuck my foot in my mouth in regards to amounts. lol
 
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#48 ·
From Kaase's web site.

The P51

In the intervening years and with ambitions to expand into broader markets, including the street performance arena, Kaase consolidated the gains made in the SCJ heads and continued to refine them. Now, with peak intake flow ratings of around 400-cfm, the new Kaase P51 variants are available directly from the Kaase factory. Of perhaps greater significance is their superb mid-range flow characteristics (see table below).

Commendably, Kaase retained the 72 cc combustion chambers, which allow users to run pump fuel. This chamber size also permits experimentation with different compression ratios: employing slightly dished or slightly domed pistons as desired. Importantly, the P51 chambers are fully CNC-machined, and contain larger 2.250-inch intake valves. The standard size exhaust valves are retained. The P51 heads function with the original rocker gear, but require longer pushrods because of altered valve geometry. For convenience, intake and exhaust port locations are unchanged.

Kaase P51 flow chart (at 28 inches of water) reveals exceptional mid-range flow

Valve Lift (inches)Intake (cfm)Exhaust (cfm)
0.1007252
0.200152107
0.300234151
0.400306183
0.500350202
0.600368215
0.700388229
0.800395239


I hate flowbenches. As you may know, most of our work is with 815″ Pro Stock engines. On these heads the flow bench is almost totally worthless. I think it’s misleading at best. We can port an older aluminum A-429 CJ head to flow 400 & 250. Then we can have a P-51 head that flows the same. The P-51 will dyno75HP better than the CJ. It’s all about sizes, areas, shapes, and valve placement in the bore. I think you’ll find that the more an engine builder uses the dyno, the less he trusts or even uses the flowbench. There are so many flowbenches out there in use that almost everybody thinks he’s an expert.

One of our main goals when engineering these heads was to be able to deliver them with 400 cfm intake ports. We have reasonably well achieved that goal. In high flowing intake ports with the port opening positioned down close to the head gasket surface, the air often breaks away from the port floor and results in turbulence. This usually occurs above .600″ valve lift when the air flow is high. With the P-51 head, some of the intake ports will be smooth and quiet all the way to .800″ lift. Those ports will usually flow over 400 CFM. Some of the ports will go turbulent at .550″-.650″ lift. When it happens, the sound changes and the airflow will drop off about 20CFM. The flow will be the same or better than the well behaved port right up to the lift where it goes turbulent. There are several ways to fix this, all of which are not a good idea. If we raised the port entry about 1″ at the manifold, it would be a big help because the air would not have to make such a sharp turn. Of course none of the manifolds would fit. If we made the port a lot wider or taller at the short turn, that would fix the problem because the air speed would be much slower. But slow is not what you want in a good performance or race engine. When flowing one of these problem ports, sticking a butter knife or blade in the floor of the port will usually straighten it out to flow 400. We have dyno tested engines with heads that flowed 400 and then changed to heads where every port went turbulent to flow 375. They both made the same power. Now, if you ran a set of heads that flowed 375 because of improper porting or seat work, and then reworked them to flow 400, they would for sure make more power.

At the 460FORD.com engine tech seminar in Owensboro, KY, I had a client tell me that he replaced a set of A-429 heads (Ford aluminum Cobra Jet) with P-51’s. He was thrilled to have a 100HP increase! I think this would be on the high end, but I think 75 would be realistic if it was a good, sound engine with at least 256 degrees of camshaft. We have run enough different combinations to be able to say that a well prepared 466 will make about 700HP. A 514-521 will make 800HP. This would be with as delivered P-51 heads, at least 256 degrees of roller cam, an un-modified Edelbrock Victor 460 (or Ford counterpart) and a Dominator type 1150 carb.

jonkaaseracingengines.com

Kaase P-51 Cylinder Heads

P-51 aluminum cylinder heads for Ford 429/460 big-block engines, the 385 series. Earlier this decade, Kaase demonstrated their considerable engine-design talents when they corrected longstanding fa…
jonkaaseracingengines.com jonkaaseracingengines.com
 
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