Roller LA cam in a Magnum?

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318willrun

318willrun

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I've always built and played around with the LA small blocks, but have never did anything with the magnums. I've owned a few magnums in vehicles, but never attempted to do anything with them as far as installing them in older vehicles.
Here is my question: Can I take a roller cam out of an LA '89 360 (TBI) and install it in a 5.2/5.9 magum?? The reason I'm asking is I would want to run a mechanical fuel pump (it would be carbureted) with the LA timing chain cover. The '89 motor has the fuel pump lobe bolted to the front of the cam, and the magnum cam from what I understand doesn't make provision for it. I also heard that Hughes makes a piece that would allow the fuel pump lobe to work on a magnum cam. Anyone try this piece through Hughes???
P.S. Please do not tell me to "search" past threads. Did this and found nothing. Yes, I've read the articles on LA and Magnum differences. I did not find the answer to my question.
 
I believe you can run a LA style roller cam in a Magnum. I'm looking to do the same thing down the road for the same reasons. From what I have read the Hughes piece gets mixed reviews at best. pretty sure you need to run the Magnum style lifters to provide oiling threw the pushrods to the rockers.
 
you can use any of the retrofit roller cams or la roller in the magnum motor, so that use can use a mech pump
 
To answer your question yes. The 89 roller cam has the long snout for fuel pump eccentric. Also the lift specs for the 89 roller are based on 1.5 rocker ratio, putting it in a magnum motor with 1.6 ratio will result in a poor mans low duration higher lift cam in a magnum motor. Make sure you check piston to valve clearance with any cam change. Also any listed hyd roller retrofit LA cam will have the long snout and will work in a magnum engine using a LA timing cover.
 
Yes, the cams are interchangeable. between the 89-91 engines and the Magnums.


Hughes slipped us a mickey. I ordered a cam with the "snout" for the mechanical pump for our 91 360 and told them that I wanted the proper cam for my application. They sent me the magnum cam (no nose for the mechanical fuel pump) and a "band aid" backwards assed engineered "nose extention" kit for an additional $30 dollars instead of shipping me the proper one with the right nose. (How nice of them to find a way to charge more and not give me what I asked for). I had to rework their "adapter kit" as I wasn't comfortable with the way that they designed it.

So the roller camshafts are the same except for one has a nose for the mechanical fuel pump, and the other doesn't.
 
Yes I did this in my magnum 360 Dart. Had comp custom grind me a cam on a 90 LA core. Works perfect and I run a mechanical fuel pump.
 
True story...it does work but as kuda said-it requires machining to perform it's function (don't ask me why they don't sell it machined to begin with...I already asked Hughes on the phone and they couldn't provide a legitimate answer). IIRC, my machinist took 0.105" off the open end of the cup washer and it all mated together satisfactorily.

). I had to rework their "adapter kit" as I wasn't comfortable with the way that they designed it.
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Yeah...I'm pretty sure they did that on purpose...and like I said above, no idea why.

If I were to do it again, I'd just either buy a custom LA roller cam like Walker did, or have a stock LA cam reground by Oregon.
 
Well that confirms what I've heard about Hughes. I've never used them and don't plan to! Thanks for the info. guys.
 
Thanks for the great info so far on this subject. Of course, the magnum lifters/push rods would be used with the LA cam because of oiling purposes, correct?
 
70 DUSTER CRATE said:
Well that confirms what I've heard about Hughes. I've never used them and don't plan to! Thanks for the info. guys.
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If I were you, I wouldn't allow my soured experience to sway your decision as it's only one of many experiences. The parts worked-but I was pissed because I had to spend another $30 and a two trips to the machine shop to make the parts work...if they sold it ready to use for, say, $40-$45 I would've probably still gone that way at the time...with some mild grumbling. Hughes has other things going for them, and many folks are happy with their products.

Everyone has an opinion, and experience is one helluva teacher.
 
318willrun said:
Thanks for the great info so far on this subject. Of course, the magnum lifters/push rods would be used with the LA cam because of oiling purposes, correct?
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Mag lifters, yes-mag pushrods--not sure if they're the same length as LA roller pushrods...different rockers.
 
OK, just looked it up-the LA roller pushrods are showing as 6.74" length (RockAuto, 91 360, oil through pushrod), sealed power RP3277

Magnum, 6.900" length (RockAuto, '95 5.9 magnum, oil through pushrod), Sealed power RP3333

Lifter are the same though: Both examples, part numbers are the same...Sealed Power HT2269
 
agree pushrods probably not...

look at 89-91 LA engine with hydraulic roller and shaft rockers for pushrod lengths...
 
Ok. So what would I use then, the magnum lifters/push rods with the '89 cam??? Or do I need a specific push rod?
 
reuse the lifters and pushrods from the magnum. basicly change the magnum motor to the 89 roller cam and use the LA front timing cover.
 
If you're running Magnum heads, use magnum pushrods...if you're running LA heads, run LA pushrods...
 
318willrun said:
I would use the magnum heads, so I will run the magnum pushrods.. thanks
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Highly recommend, turning the valve guides down,before installing the springs. You're limited to about .520-ish lift,on a 1.6 rocker. Running a LA "retro roller" cam based on a LA 1.5 lobe lift, leads to high lift numbers.Would still recommend a push rod length check,the stockers are usually too short,on a reduced base circle aftermarket grind. Magnum swap,com,has a listing of a affordable Comp Cams push rod set(30-40 bucks).Hope this helps.
 
Would still recommend a push rod length check,
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Indeed-always a good idea. Ran into issues like this with SBFs with the pedestal mount rockers. They'd always wind up noisy because too little preload.
 
txstang84 said:
Indeed-always a good idea. Ran into issues like this with SBFs with the pedestal mount rockers. They'd always wind up noisy because too little preload.
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Yes. I went with Crane's conversion kit,and Comp's 1.5 rollers. Forgot about the 1.6 ratio,pegged the springs too tight at .550+ lift. (Oops!) I prefer adjustable valve train anyway, lol.
 
I've also read where the older heads (don't know what you are running) don't have enough clearance for the pushrods with a roller cam, because the taller roller lifters change the PR angle through the heads, I believe.

I'm "about to find out" about this if and when I get my J heads back which are going on a roller block. I will however be using the smaller dia. adjustable pushrods, which I hope to be able to shorten myself.
 
302 and 308 heads have the larger pushrod tube openings, 5/8 inch. If you use the j heads you'll need to clearance the smaller openings for sure.
 
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