Modifying the Holley HyperSpark distributor 565-315 (made for the "small block") to work with a "big block " Ford 240 six or 300 six

Baxsie

Baxsie

Well-known member
Spoiler alert: Just get a ford EFI distributor and save your money.

So I did not know about big vs small for sixes, so I ordered a Holley HyperSpark distributor 565-315 thinking it would fit in my 240.

It is pretty obvious that it is not a drop-in replacement:

comparing_distributors.jpg

The hole in the block is ~1.4". The Holley 565-315 is ~1.3". Plus the gear is different. And the oil pump drive shaft needs to be longer.

First I turned some sleeves to expand the Holley 565-315 to 1.4":

Turning_Sleeves.jpg

I started with 1.5", 0.125 wall aluminum tubing. Turned the inner diameter to slightly less than 1.3", and turned the outer diameter to 1.4"

Then carefully pressed the sleeves into position using some bearing retainer to make sure they stay put. I left a small gap between the sleeves for the o-ring to live:

Pressing_on_sleeves.jpg

Here are the dimensions of the parts. For a competent machinist, these should be cake to make. It took me a long evening on my cheesey HFT mini-lathe.

Dimensions.jpg

The oil pump drive shaft needs to be longer. I cut down a 5/16 long-handle, ball end Allen wrench. I re-used the little circlip from the original rod. As far as I can tell, the circlip is only used to hold the shaft in the distributor during installation.

Oil_Pump_Rod_Length.jpg

Here is the finished mod (larger Holley o-ring shown, need a 1/16 cross-section o-ring):

Oil_Pump_Rod_Installed.jpg

I did have to use some emery cloth to get it to fit into the block. Pressing the sleeves on expanded them slightly.

Install.jpg

I have a 1 1/4 ID, 1 3/8 OD, 1/16 cross section o-ring on order, but other than that it seems to work:

Installed_no_o_ring_yet.jpg

I did check to make sure that the distributor shaft has some vertical play -- if there is no vertical play that might indicate that the oil pump rod is too long.

Use at your own risk, your mileage may vary, I have not tested it yet, if this mod spews parts into your crankcase and destroys tour $30,000 hot rod engine build that is on you . . . etc.
 
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Wow that was a lot of work to get that small six Distributor to fit, dose the center shaft extend down far enough to fit into the block lower support pilot hole? It dose look good setting in the engine!

It used to be a common mod to slot the older Carb Mounting Holes so they would fit onto the wider style of mounting studs that ford changed to in about 1969 and that works out quite well. Another way would to be to make an Aluminum carb adapter spacer out of 1/4-to-3/8-inch material with a taper to match to two different hole sizes. I think you could also adapt the 2V Holley Sniper to the stock intake if you wanted to, this has been done by one site member on his 1967 or 68 200 six which is a small Log head with a 2V to 1V carb adapter, he got good results with it. If you do that with the 2V to 1V adapter also open up the intake carb mounting as much as you are able and still have a good gasket purchase. On the Large Log 200 / 250 heads you can go to 2 inches easy, and some have gone to as much as 2 1/8 inches (in this case Bigger is Better) also open up the 1V part of the Carb adapter base to match too. Best of luck
 
bubba22349 said:
. . . does the center shaft extend down far enough to fit into the block lower support pilot hole? . . .
Click to expand...

My ignorance hits again. I guess that you mean that the shiny bit highlighted here is supposed to ride in a bushing of the cylinder block ?

Lower_Support.jpg

I doubt that the found shaft in the Holley is long enough to engage with that hole. I should go measure. I'm guessing that is not going to be an easy fix - I'd have to make a longer shaft that is otherwise identical to the Holley shaft. Bleh.

I guess I could cut off the bottom of the Ford shaft, use the hex shaft to align it, and tig weld it to the Holley shaft, then turn down the weld. That sounds dodgy even for me.
 
Baxsie said:
My ignorance hits again. I guess that you mean that the shiny bit highlighted here is supposed to ride in a bushing of the cylinder block ?

View attachment 10990

I doubt that the found shaft in the Holley is long enough to engage with that hole. I should go measure. I'm guessing that is not going to be an easy fix - I'd have to make a longer shaft that is otherwise identical to the Holley shaft. Bleh.

I guess I could cut off the bottom of the Ford shaft, use the hex shaft to align it, and tig weld it to the Holley shaft, then turn down the weld. That sounds dodgy even for me.
Click to expand...
Yes exactly right the shinny part of the shaft is where it fits into the pilot hole of the block. Yes everything from the block hole collar on down needs to match up fairly closely with those of the 240 / 300 six distributor. I don't think it would be all that bad if the lower section of the 240 distributor was tig'ed onto the bottom of the Holley shaft or a collar made and a couple of pins used to lock it together, seeing how well you made those adapter parts I think you could pull that off, also remember that the distributor is only turning at 1/2 of engine RPM.
 
Yes, you have a little more handy work to do. Is the pilot the same diameter? The gear should be turned around and all measurements made the same.
There Is probably more than one fix. One is If you take it all apart and machine the mounting collar off and the lower area the same diameter as above the collar mount and make a new adapter with a collar and o- ring grove, make it long enough to help support the lower bearing, then if there is space to slide the dist. down the distance you need. This should give you bearing support where you need it.
 
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One other thought on of above. If again there is room to lower the dist. down a custom two-piece split collar adapter would be less fussy machining, just remove the machined collar and lower the dist.
 
The most important piece is that the distributor gear is centered on the camshaft gear.
The gear depth from the bottom of the hold down flange must be the same for both distributors.
 
pmuller9 said:
The most important piece is that the distributor gear is centered on the camshaft gear.
The gear depth from the bottom of the hold down flange must be the same for both distributors.
Click to expand...
Pual do you have that spec? In the Classic Tech page, the small six spec. looks right to me and the big six looks wrong. and yes it must be adhered to.
 
On the Ford big six distributor, I measured the center of the gear from the base of the distributor at 2.4 inches.

The 0.400 long steel spacer is what enforces this dimension on the Holley mod.

Lowering the entire distributor is an interesting idea. At some point, the body will intersect with the engine block.

My first idea was to transplant the Holley electronics and shutter into the Ford body. That would have solved all the mechanical problems, but probably opened up several other new and different problems.

Part of me just wants to try it without a lower support. How much force can there be on the gear to just spin the distributor?

On the other hand, if the gear slips a notch, the engine will stop. If it disassembles itself it will likely destroy the engine.

I'll probably try to extend the shaft so that it pokes into the lower guide. Fiddly but should work.
 
I like the idea of grafting the top of the Holley dizzy to the bottom of the old ford dizzy. There must be a way!
 
Baxsie said:
Part of me just wants to try it without a lower support. How much force can there be on the gear to just spin the distributor?
Click to expand...
It's not the distributor that needs any force to turn, it's the oil pump.
It takes a lot of force to keep the gears engaged at 60 psi of oil pressure at 3800 engine rpm.

I've been hesitant to tell you this, but the 1987 and later EFI 4.9 distributors are Hall effect with the same rotating vane arrangement as the Holley distributor.
There is one vane spacing that would need to be modified so all signals have the same time interval, and it would be good to go.
 
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If I was trying to save it. I would start by measuring the exactly the stock 300 dist, pilot length to gear, not turned around, the distance from the bottom of mounting collar to the bottom of gear the whole part, that is the way ford specs it. Put the gear on the right way on the 200 dist. at the right pilot length. Now figure how much you need to move the collar . A spacer like you made will help, it will be about the difference of the longer 200 pilot length and the shorter 300 factory length, just do not make it to long it will put extra load on the shaft.
 
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pmuller9 said:
It's not the distributor that needs any force to turn, it's the oil pump.
It takes a lot of force to keep the gears engaged at 60 psi of oil pressure at 3800 engine rpm. . . .
Click to expand...

Another layer of my ignorance uncovered. So I need to think of this as primarily an oil pump drive system first, and "oh, right it also drives the distributor". So if I was trying to further modify the Holley, the trick would be to weld the top 2"~3" of the Holley shaft onto the Ford shaft. That way all the oil pump stress would be below the weld, and only the nearly negligible friction of the top bushing and rotor would be above the weld.

This also brings up a nagging concern I have about the Holley design. At the top, there is a nice bronze bushing. But at the bottom (where I now know there is the stress of the oil pump drive) it appears that the distributor shaft just rides in the aluminum bore. Also, inexplicably, there is no path to allow engine oil to lubricate this lower shaft support.

pmuller9 said:
. . . the 1987 and later EFI 4.9 distributors are Hall effect with the same rotating vane arrangement as the Holley distributor.
There is one vane spacing that would need to be modified so all signals have the same time interval, and it would be good to go.
Click to expand...

Knowledge is power - - I try not to succumb to the sunk cost fallacy. Something like this?

1987_Distributor.jpg

These guys are local, for $37 I'll go get it just for parts or reference.

I may have called the Holley sensor a Hall Effect sensor, but I think more properly it is a Variable Reluctance sensor. Minor point -- the 1987 Ford and the Holley probably use the same style.
 
Baxsie said:
I may have called the Holley sensor a Hall Effect sensor, but I think more properly it is a Variable Reluctance sensor. Minor point -- the 1987 Ford and the Holley probably use the same style.
Click to expand...
It uses a Hall Effect Sensor if there are 3 wires, one for power, one for ground and one for signal.
It is listed as a Hall Effect unit.
The Hall effect signal is a 12-volt square wave and is far less susceptible to RFI than the VR signal.
 
The pilot carries most of the gear load that is why that part needs to be as designed.
I asked if the pilot were the same size, are they? If I had a 300 I could help more with out one I am assuming some physical things.
I could carve a block of wood by memory of a 200 and paint it blue and no would could see the difference. 300 not so much.
Looking closer as the 300 dist ,the way it tappers down I assume for clearance, the 200 my not have enough Clearance there ,something to think about.
 
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