EFI conversion on a Magnum 360 crate motor

[blkmagnumgt]

[FONT=Verdana, Arial, Helvetica, sans-serif]Back in 2005 I bought this crate motor from Summit for $3499. Its a new, not rebuilt, Mopar Magnum 360. ( It was classified as a Magnum 380, This is the 380 hp, 411 torque) It recommended a 750 carb, and is not recommended for A/C. Keeping it tuned has been a chore, going through a set of plugs every few months. Plus it has a nasty, nasty cam when timed to where it runs correctly. My question is, I've thought about converting to EFI. Either getting a stock EFI manifold from a newer Magnum engine, or getting one of the EFI kits, that either replace the carb, or the intake. Question, If I do the conversion, will it run LESS radical with the cam, since the timing will be controlled by the unit, and if I used stock engine configuration, any chance I might be able to run A/C? The Mopar intake on it now has the thermostat housing closer to the passenger side, thus making stock A/C location unusable. Since this IS a production Mopar performance engine, any chance their is a set up designed for this specific engine?[/FONT]

[FONT=Verdana, Arial, Helvetica, sans-serif]PS [/FONT]
[FONT=Verdana, Arial, Helvetica, sans-serif]Bottom line, I removed this engine, and swapped a mild 360 ( Much to my friends surprise ) because using premium fuel, I get valve clatter if i stomp it, and diesels at idle if the RPM's rise. Don't get me wrong, its the most powerful motor i've ever owned, as my brother calls it, A race motor.. Can it be a little more civilized? [/FONT]

 

[dpstark2]

Hi,

Hopefully others will chime in here too- but in general, EFI will not drastically change the character of the motor. In fact, in order to run EFI effectively at all, you'll probably have to do a cam swap. To that end, you could probably get half way to your goal with just a cam swap. Do you know the cam specs for your motor? There is conflicting info on the internet. If it is indeed a 108 LSA, going to 110 or 112 would calm it down a bit. Depending on your compression (another unknown), you might not be able to reduce duration much without affecting dynamic compression too much. And depending on the EFI conversion you choose, it may not control your timing at all- you might be stuck with a distributor.

Overall, if your goal is a less radical motor and A/C, you might just consider a cam/intake/valve spring swap for a lot less effort and similar effect. More knowledgeable people here can suggest a specific cam. I just had to chime in on the EFI aspect...

 

[blkmagnumgt]

Thank you for your input, what you said makes since. The only way to mellow the engine is to de-tune the power from the engine. I was looking for my OLD summit catalog to see the cam specs., but at the moment it seems to be missing. I think it would be a sin to break the motor down and remove what Mopar put together, as a performance engine. Perhaps I should think of getting another Mopar project going that I could use this engine unmolested.

Thanks again for your reply!

 

[RustyRatRod]

How can it be new in 2005 when the last Magnum engine was made in 2003?

 

[blkmagnumgt]

How can it be new in 2005 when the last Magnum engine was made in 2003?

Bought it January 2005 from Summit racing. The motor was on back order, and I had to wait 3 weeks. The Mopar magnum with 320 hp was in stock, but my 380 took some time. claimed to be be a NEW production performance block from Mopar Performance. 380 hp with 411 torque

 

[blkmagnumgt]

Based on the production Magnum 360, the 380-horse crate is built with all-new parts, not the usual rebuild. Inside the bottom end you'll find pump-gas-friendly 9:1 pistons, a hydraulic roller cam, and a double-roller drive. The roller is a fairly stout stick, with a long .288 intake, .292 exhaust duration, and .501/.513 lift-much more than any production small-block. The specs don't hide the fact that this cam will have some bark, so if the lope, rumble, and top-end power aren't the goal, consider backing off to the milder 360/300hp version.

Topping the short-block is a set of Mopar's now-familiar high-swirl closed-chamber Magnum cylinder heads. The 1.925-inch intake valves are slightly smaller than those of the early 340, while the 1.625-inch exhaust valves are slightly larger. As with all Magnum engines, 1.6:1 rockers are standard. This is a tenth of a ratio point higher than the traditional 1.5:1 small-block rockers of old.

The major benefit of the Magnum heads over the old 340/360 castings is the nicer form in the exhaust port. The old small-block Mopar heads had a definite flow-inhibiting area in the most critical portion of the exhaust port floor, right as the port departed from the valve seat. Also restricting the exhaust flow was a big kink in the port roof. The Magnum exhaust port is much improved. On the intake side, the port window is narrow through the pushrod area, owing to the larger clearance hole used in conjunction with the hydraulic roller cam's valvetrain. Toward the valve, the Magnum head's ports take a nice form. The most significant departure from the Mopar small-block heads of old is the combustion-chamber design. The best features of the old heads were retained, including the valve angle and favorable opening axis to the centerline of the bore. The chamber has been redesigned to take advantage of the better combustion characteristic available from a modern closed-quench chamber. This chamber design alone should produce a worthy increase in output over the old-style open chamber heads.

The Magnum crates are shipped with a large cross-section single-plane M-1 aluminum intake manifold, which appears to be a nice design, utilizing a modern sweeping runner. Bosses are cast into the intake, allowing for a multi-port fuel-injection system, although a standard four-barrel carburetor is the induction of choice for most installations. The Magnum crate is fitted with a center-sump oil pan, which is compatible with traditional Mopar body styles. Rounding out the package, the crate comes equipped with MP cast-aluminum valve covers, a damper, the dipstick and tube, as well as the water pump. A complete Mopar Performance electronic ignition system and thermostat housing are included. Add a carb, headers, and accessories, and it's ready to run



Read more: http://www.moparmusclemagazine.com/...ate_engine_buildup/viewall.html#ixzz2Ke8u5nEV

 

[blkmagnumgt]

You got me curious if I bought an older ( as you say 03 ) Magnum block, but I haven't found anything saying they ended in 2003. Where did you hear that?

 

[RustyRatRod]

From Wiki:

"Following suit: 5.9L Magnum V8

In 1993, Chrysler Corporation released the next member of the Magnum family: the 5.9L V8. This was based on the LA-series 360ci engine, and included the same upgrades and design features as the 5.2L. The standard 5.9L created 230 hp (170 kW) @ 4,000 rpm and 330 lb·ft (449 N·m) @ 3,250 rpm. However, Chrysler came out with the performance-oriented R/T version in 1998. This engine was provided with a more aggressive camshaft profile, and it was rated for 250 hp (190 kW) and 345 lb·ft (469 N·m). The 5.9L R/T came factory-installed in 1998-2001 Dodge Dakota R/T pickups and Dodge Durango R/T SUVs. It was also installed in the Jeep Grand Cherokee Limited 5.9, only available in 1998. The 5.9L Magnum was available until the 2003 model year, when it was replaced with the 5.7L Hemi V8 engine.[11]

Although the pre-Magnum ('71-'92) and Magnum versions of the 360/5.9 are both externally balanced, the two are balanced differently (the 360 Magnum uses lighter pistons) and each requires a uniquely balanced damper, flywheel, drive plate, or torque converter. Bore size was 4.00", stroke was 3.58"; compression ratio was 9.1:1."

 

[arizona satellite]

How can it be new in 2005 when the last Magnum engine was made in 2003?

the "production run" ended in 2003, not production of the engine. the last magnum installed in a production model vehicle was in 2003 that is all that means. your engine WAS a NEW engine when you purchased it. it is now 2013 and you can still buy a NEW 426 HEMI and they stopped production in 1971. now to your efi question, I have sold a few profession products EFI kit ProJectionIII ,and the cars have had large roller cams( not a mopar engine, pontiac 462 with a 656" lift roller and 9.5-1 comp) the engine behaved much better then with an 850 holley, strart up and idle quality went through the roof. we also picked up some ET at the track.

 

[RustyRatRod]

It clearly says the 5.9 was available until 03 when it was replaced by the Hemi. It's talkin about the engine, not the car.

 

[blkmagnumgt]

Not wanting to sound disrespectful, but you said, (How can it be new in 2005 when the last Magnum engine was made in 2003?) Then you explained it was production Magnum engines installed at the factory that ended in 03. When I clearly showed a pic of a crate engine, that WAS new in 2005, so WHY even say it wasn't new, when It ACTUALLY was....

 

[RustyRatRod]

I never said it was not new. I simply asked a question.