Ideas? On a drill jig for converting Magnum heads to LA intake

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67Dart273

67Dart273

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I think I'm going to try to build a drill jig to drill Magnum heads for LA intake At this moment, "the plan"

1....Take an LA head for a pattern, doesn't matter so much but MUST NOT be milled!! LOL

2....Two, maybe three flat straps say, 5/16 thick X 2 wide or so, which will sit on the cylinder surface, and locate the jig definitively using through bolts in the head bolt holes, 2 or 3 places. These straps will be welded to the jig, as they will be sticking out past the intake flange surface.

Drill these head surface pieces, provide a method to index them to the head bolt holes

Perhaps some sleeves that are a slip fit in the head bolt holes to provide reasonably accurate indexing, with minimally oversize sleeve inner holes for 5/16 or 3/8 bolts in the sleeves, depending on what I find

3...Suitable piece big enough to cover the intake ports and bolt holes, 1/4 thick X3 wide or whatever.

4..Using the head / cylinder surface as a "height zero" mark the height of the holes on the main jig strap. Then simply mark off accurate distance between intake bolt holes. These can actually be drilled OVERSIZE and actually don't have to be that accurate

5...Obtain sleeves to slip fit bolts for the intake bolts. Install the main piece, install the sleeves, and clamp them to the head with through bolts into the intake bolts.

6....So now you have the main jig piece clamped to the head via the intake bolts, the sleeves clamped to the main piece by these bolts, and you have installed the straps that bolt through the head bolts

7.....Kidnap a friendly TIG welder, and weld the main piece to the head surface straps, and all the sleeves to the main piece.

8....Paint if you really must!!!!

Thoughts/ alterations?

Here is one version:

I found another on here, but it's a photobucket "thing" and I guess you know how that crap went. Almost as bad as the "improved" software on here

Link to the thread:

Post no.20

What to do with my 360 magnum??

100_0339.jpg
 
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If you only have one set of your own to do, and you don't own a welder, it would be just as easy to mark your heads using a gasket as a template and then borrow drill press time to ensure they are drilled straight.
If you have access to a welder, building a jig like the picture you included would be a cool task.
I have one of the dual pattern intakes and may try using it as a template or even a drill guide.
 
Well, LOL, I was even thinking someone might want to rent / borrow it. If successful, this will NOT be a high profit item LOL
 
there was a similiar jig floating around on the internet, same deal: use it and send it to the next guy on the list. I would think a crosswind intake or other dual pattern intake would make an ideal drill guide, then tap.
 
Not sure about that Pishta. I think there is no "straight shot" into the angled LA holes. I don't think you can just mark them, either, I believe the magnum holes "interact." That is I don't believer there's a clean surface for a transfer punch, etc.
 
67Dart273 said:
Not sure about that Pishta. I think there is no "straight shot" into the angled LA holes. I don't think you can just mark them, either, I believe the magnum holes "interact." That is I don't believer there's a clean surface for a transfer punch, etc.
Click to expand...

I have seen that borrow jig around as well, but don't remember where.
 
I thought I remember hearing that it "disappeared" after someone got their hands on it..........
 
67Dart273 said:
I think I'm going to try to build a drill jig to drill Magnum heads for LA intake At this moment, "the plan"

1....Take an LA head for a pattern, doesn't matter so much but MUST NOT be milled!! LOL

2....Two, maybe three flat straps say, 5/16 thick X 2 wide or so, which will sit on the cylinder surface, and locate the jig definitively using through bolts in the head bolt holes, 2 or 3 places. These straps will be welded to the jig, as they will be sticking out past the intake flange surface.

Drill these head surface pieces, provide a method to index them to the head bolt holes

Perhaps some sleeves that are a slip fit in the head bolt holes to provide reasonably accurate indexing, with minimally oversize sleeve inner holes for 5/16 or 3/8 bolts in the sleeves, depending on what I find

3...Suitable piece big enough to cover the intake ports and bolt holes, 1/4 thick X3 wide or whatever.

4..Using the head / cylinder surface as a "height zero" mark the height of the holes on the main jig strap. Then simply mark off accurate distance between intake bolt holes. These can actually be drilled OVERSIZE and actually don't have to be that accurate

5...Obtain sleeves to slip fit bolts for the intake bolts. Install the main piece, install the sleeves, and clamp them to the head with through bolts into the intake bolts.

6....So now you have the main jig piece clamped to the head via the intake bolts, the sleeves clamped to the main piece by these bolts, and you have installed the straps that bolt through the head bolts

7.....Kidnap a friendly TIG welder, and weld the main piece to the head surface straps, and all the sleeves to the main piece.

8....Paint if you really must!!!!

Thoughts/ alterations?

Here is one version:

I found another on here, but it's a photobucket "thing" and I guess you know how that crap went. Almost as bad as the "improved" software on here

Link to the thread:

Post no.20

What to do with my 360 magnum??

View attachment 1715170204
Click to expand...
Just Awesome, Del!!!!!!!!!!!!
Thinking outside, the box !
 
I remember that jig on moparts. I think it was about 12-13 years ago.
 
67Dart273 said:
Not sure about that Pishta. I think there is no "straight shot" into the angled LA holes. I don't think you can just mark them, either, I believe the magnum holes "interact." That is I don't believer there's a clean surface for a transfer punch, etc.
Click to expand...
your right, the holes do share some real estate. I think if you could sink a carbide burr or an end mill into the guide, you could make a pocket that a smaller drill could find and then create a pilot hole. Not something I would try with a cheap bit. If you got the know how, go for it, sounds like you got a good plan.
 
Yeah, that was Moparts, long time ago, and I think his screen name was Ranger-something... Rick maybe? That was before there were any Magnum carbureted intakes for a Magnum engine. It might even have pre-dated the MP intake - so there was "a need".
Honestly the drilling isn't hard for a shop or anyone with a drill press or Bridgeport, or you can buy an intake for less than $250.
 
The holes on the dual pattern intakes do intersect, but there is enough material to use as a guide to mark it, or even a guide to drill the front and rear holes. Once those are drilled and tapped, a simple flat square stock with tubes can be fabricated very cheap and easy to use as a guide.
If you are buying an LA intake anyway, set the intake in place with gaskets, line up the ports, and use the LA intake to mark the heads.
Here is pic of the head-side of a dual pattern intake showing the intersection.
IMG_20180429_111602.jpg
 
67Dart273 said:
LOL!!!! Found that last night doing a search!!!! Thanks for the thoughts tho!!
Click to expand...
No problem! I had it saved somewhere. I’m sure it is pricey. But then again, the E-Z button always is.
 
Bobzilla said:
The holes on the dual pattern intakes do intersect, but there is enough material to use as a guide to mark it, or even a guide to drill the front and rear holes. Once those are drilled and tapped, a simple flat square stock with tubes can be fabricated very cheap and easy to use as a guide.
If you are buying an LA intake anyway, set the intake in place with gaskets, line up the ports, and use the LA intake to mark the heads.
Here is pic of the head-side of a dual pattern intake showing the intersection.
View attachment 1715170345
Click to expand...

Thanks!!

One thing I'm "skeered" of is getting the hole set too high or too low, creating a situation similar to having the heads milled. That is, you set the intake in place and the holes are offset vertically LOL
 
I just sent out a set of Magnum heads that I converted to LA bolt pattern. For those considering using a double drilled manifold as a template, they do not have the bolt holes drilled at the correct angle. Someone must have thought a SB Mopar and a Chevy were the same.

20180309_200144.jpg
 
Thanks for the info. "Marvelous" to the Chineseoationized "machinist"
 
As much as I like home brewed engineering, probably better of just using a magnum intake. Unless you're hell bent on using something that don't come in mag flavor.
 
That’s the problem skrews, there are a limited amount by of intakes (& heads) avalilable and MoPars are now gone. That’s 2 for the carb guys. Then there’s the RPM, Indy and the Chinese knock offs.
 
rumblefish360 said:
That’s the problem skrews, there are a limited amount by of intakes (& heads) avalilable and MoPars are now gone. That’s 2 for the carb guys. Then there’s the RPM, Indy and the Chinese knock offs.
Click to expand...

Plus they cost money The intakes that is. Plus I have a number of mag cores, "a couple of which run" and might be easy to freshen up. Plus I have some experiments I want to do with EFI and that does NOT include "magnum" intakes, beer keg, or otherwise.
 
pishta said:
Do tell.....Im interested.
Click to expand...

Oh, LOL you have already seen the beginnings of SOME of them. My "inventory of EFI crap loosely, here and there

1...Old holley Pro-Jection I think it's a "2D" tuned with pot adjustments on the box

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2...Holley Commander 950

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3...Upgraded the Commander to a Holley HP computer
4...Someone in Spokamentro gave me the stuff off a 460? Ford I think "some of it is" there
5...Member here gave me some stuff which I someday hope to........
6...Various parts and pieces of Mopar EFI
7...Couple of Ebay TBI that were sorta destined for the Commander/ Pro-Jection.........???
8...Bought a used basic FItech..................
9...AND THEN THERE IS THIS............

You guys ARE NOT GONNA GUESS what Del scored!!!

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10......and somewhere along the way I blew about 500 bucks on a Megasquirt just to put together and play with. I STILL DO NOT have it done, either

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When I die, they are gonna think I was either a mad scientist, or a very crazy old guy
 
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