Any reviews on a 360 magnum crate motor P5249499

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shootr2506

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hi all I just bought this Mopar 360 crate motor part number P5249499 from a guy who never got around to putting it in his duster .It’s going in my 71 dart with a 727 tranny and a 8 3/4 posi rear with 373 gears and just wanted to know if anybody used this motor in a A body and where you satisfied with its performance.thanks Also I’m confused about which flex plate to use .mopar tech support says use the external balance one ,but I noticed that some come completely round and others come with the half moon cut out type.l need help on this one thanks all .
 
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Is that the dual plane intake one ~320hp?

Or the single plane ~380hp.?

Ns1rm21, sold a ton of each at Westoaks MP back in the day. IIRC, the 380hp often had a bigger cam than the 100% street driven turn the ignition key type buyers could tune and live with (eyes bigger than their stomachs). Those people expected it to be maintenance free like a new car.

I think their are more evolved street-able cams to get to the same HP on the market today. Or something with same drivability that makes more HP.
 
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autoxcuda said:
Is that the dual plane intake one ~320hp?

Or the single plane ~380hp.?

Ns1rm21, sold a ton of each at Westoaks MP back in the day. IIRC, the 380hp often had a bigger cam than the 100% street driven turn the ignition key type buyers could tune and live with (eyes bigger than their stomachs). They expected it to be

I think their are more evolved street-able cams to get to the same HP on the market today. Or something with same drivability that makes more HP.
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I have the 380 Hp 360 magnum thank you
 
shootr2506 said:
hi all I just bought this Mopar 360 crate motor part number P5249499 from a guy who never got around to putting it in his duster .It’s going in my 71 dart with a 727 tranny and a 8 3/4 posi rear with 373 gears and just wanted to know if anybody used this motor in a A body and where you satisfied with its performance.thanks
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Pull the oil pan and check the torque on all of the mains and connecting rods before installing... They had a problem with loose connecting rods on the crate engines for a while...

Don't loosen them first, just tighten them to check the torque so you don't put extra clamp cycles/stretch in them....
 
Since it has been sitting a while, I would suggest checking almost everything. Many of these were slammed in and run out of the box, but It's easy to check before you install it.
I have Mopar Magnum short block in my truck that has 100,00 miles now with no issues at all.
I also currently have a Mopar short block my brother aquired some time ago and sat around until I recently took it over. This one had a piece of wire from a wire brush or wire wheel stuck under the head of one of the rod bolts. I was taking it apart anyway to enlarge valve notches in pistons and also found the camshaft bearings binding badly enough that the short block was hard to turn over with a long breaker bar. Could not turn it by hand even with timing chain removed.
Finally, the oil holes in the crankshaft are very sharp and are tearing up the rod bearings pretty deep even though it's never been run, just rotated by hand with the breaker bar.
As a side benefit while disassembled, those heads are worth cutting down the guides, since they will be brand new castings, then you can run a much better camshaft. That camshaft was a weird compromise because of the short retainer to guide clearance.
 
If it comes out ok, you can zoom in on the picture after clicking on it and the wire is visible, although very small.

IMG_20170507_185401.jpg
 
This one better shows the bearing damage with zero run time. The lines in the bearing are deep. The wire under rod bolt may be visible too.

IMG_20170507_185820.jpg
 
Are those speedpro pistons flat top? And how deep in the bore where they? That's some shoddy work for sure. That engine wouldn't have lived long :wtf: Ma Mopar charges big bucks for those too!
 
I will have to try to find my notes as I don't remember how far down they were. It was a weird short block that was not well thought out by Mopar, as usual. It was Magnum based, .020" overbore with hypereutectic flat top pistons, balanced like an LA engine, and intended as an LA replacement short block (Magnum block drilled for LA head oiling). The biggest problem was it had valve reliefs that were too small diameter for a 2.02 intake valve size, which I would guess most LA engine users buying this short block would be running or upgrading to when rebuilding their heads. And it came assembled with a hydraulic flat tappet camshaft.
 
The core parts in the short blocks and crate engines were good, so I think the OP has a good engine to start with. Just needs to make sure it's all ok and do a little cleanup on the detail work and will be easy 400 HP with a camshaft change.
 
Hellrats said:
Are those speedpro pistons flat top? And how deep in the bore where they? That's some shoddy work for sure. That engine wouldn't have lived long :wtf: Ma Mopar charges big bucks for those too!
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Yes they did and one of the reasons in addition to the above problems kept me from purchasing a whole engine.

The problem was Ma-MoPar wasn’t doing the work but am outside lowest bidder winning the contract was.

I was unhappy with there 10-1 shortblock. Uneven decks, slugs that went from zero deck to .013 positive.
WTF?
 
shootr2506 said:
hi all I just bought this Mopar 360 crate motor part number P5249499 from a guy who never got around to putting it in his duster .It’s going in my 71 dart with a 727 tranny and a 8 3/4 posi rear with 373 gears and just wanted to know if anybody used this motor in a A body and where you satisfied with its performance.thanks
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If the whole engine checks out OK, then you should enjoy it well. The lift limited head has a long duration camshaft that equals [email protected]. It should be used with an appropriate high stall converter to match and suite the build at hand.
 
B&M 10236 is for LA 360 engines running LA 360 external balance.
If this Mopar crate engine came in the factory blue shipping crate it may have the original paperwork with it, which should tell if Magnum or LA balance flex plate is required.
 
Mine was sitting for years still in the crate.

Less than 200 miles as we speak. Sitting in a 73 duster. I put eddy heads with rollers, ported polished gasket matched

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Heres a dyno of the 380hp create engine.

Mine works fine with a 2800 stall and 2.94 gears a little soft under 2000 rpm. Can't wait to go 4.30 or 4.56 gears though should really wake up the car.
 
273 said:
View attachment 1715228867

Heres a dyno of the 380hp create engine.

Mine works fine with a 2800 stall and 2.94 gears a little soft under 2000 rpm. Can't wait to go 4.30 or 4.56 gears though should really wake up the car.
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3200 Turbo Action 10 tight ,on mine.. and to be honest 27 inch drag radicals really need a 3:91... Throw in together, with the 3:55 's ,see how it reacts. I did a Air Gap , E.Q. heads ,and a 110 lobe center h.d ,on similar 380 /360 crate spec. It's not a smooth 112 242 /252 rat solid lifter cam ,4 sure.
 
273 said:
View attachment 1715228867

Heres a dyno of the 380hp create engine.

Mine works fine with a 2800 stall and 2.94 gears a little soft under 2000 rpm. Can't wait to go 4.30 or 4.56 gears though should really wake up the car.
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Those ratios are high for the 1/4 & the street. You will need a tall tire. Don’t get me wrong here. It’ll stomp *** for that short time.
 
rumblefish360 said:
Those ratios are high for the 1/4 & the street. You will need a tall tire. Don’t get me wrong here. It’ll stomp *** for that short time.
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Next year I want to see whats the best time I can get with the 2.94 then decide which gears to go with.
 
@273 To bad rear center sections aren’t cheap otherwise I’d say, after your done with them, then try 3.23’s, then 3.55’s, then 3.91’s, then.....

Until you max the combo out.
 
rumblefish360 said:
@273 To bad rear center sections aren’t cheap otherwise I’d say, after your done with them, then try 3.23’s, then 3.55’s, then 3.91’s, then.....

Until you max the combo out.
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Im pretty sure my uncle has 3.23 and 3.91 center sections already to go and maybe a 4.10 I could try 1st.
 
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