Posted By: JeepJimmy
300hp magnum crate 360 convert to 380hp? - 03/28/10 10:43 PM
has anyone converted the magnum 300hp 360 MP crate motor to the 380 hp model. from what i can find its only the cam and to a single plane intake. any ideas??
300hp magnum crate 360 convert to 380hp?
Posted By: Rapid340
Re: 300hp magnum crate 360 convert to 380hp? - 03/29/10 12:21 AM
Are the pistons/compression the same?
Posted By: BigDawg72
Re: 300hp magnum crate 360 convert to 380hp? - 03/29/10 12:29 AM
Everything I have seen quotes the 380hp engine at 9:1. I am using the 380HP recipe to build my 360 and have done a fair amount of research. The stock magnum engines (according to my Haynes manual) are listed at 9:1 so I would ASSUME the pistons would probably be the same? I haven't seen a compression figure for the 300 or 320 versions though.
Posted By: chache876
Re: 300hp magnum crate 360 convert to 380hp? - 03/29/10 12:46 AM
I'm pretty sure the pistons were 9:1 in the 300hp version
Posted By: HotRodDave
Re: 300hp magnum crate 360 convert to 380hp? - 03/29/10 04:05 AM
The pistons are different and slightly higher compression, the 380 HP motor I saw come appart had pistons with 2 valve releifs instead of the soap dish production pistons and 300hp pistons. They were below deck but I don't know how much but they would give a slightly higher compression.
Posted By: goldmember
Re: 300hp magnum crate 360 convert to 380hp? - 03/29/10 04:16 AM
Quote:
The pistons are different and slightly higher compression, the 380 HP motor I saw come appart had pistons with 2 valve releifs instead of the soap dish production pistons and 300hp pistons. They were below deck but I don't know how much but they would give a slightly higher compression. [/quote
Posted By: DaytonaTurbo
Re: 300hp magnum crate 360 convert to 380hp? - 03/29/10 07:36 AM
I thought the 300 horse 360 crate came with stock truck 360 pistons and regular magnum heads where the 380 horse crate 360 came with the magnum r/t heads. Not sure on the pistons on that one.
Posted By: ZIPPY
Re: 300hp magnum crate 360 convert to 380hp? - 03/29/10 01:54 PM
Change the cam, springs, retainers, and intake and you're done.
Here's the evolution of those two engine programs:
300 and 380 initially came with a stock long block right from the Saltillo Mexico engine line. Both had stock magnum heads. 380 got the cam, springs and retainers changed....300 did not.
Then MP ran Chrysler completely out of OE magnum heads, the OE supplier wasn't interested in making them anymore, and it probably would have cost 500k or more to modify the tools to fit a different foundry line.....So, enter the R/T heads and plan B:
320 and 390 had R/T heads and started out with stock Saltillo shortblocks.
That worked fine for awhile, but it wasn't long before MP ran Chrysler completely out of new OE shortblocks...and it was time for plan C:
They both got .020 over reman shortblocks with FM hypereutectic pistons, R/T heads, and otherwise the same specs as before.
380 had a stock piston.
390 in it's final, .020 over form had a better piston with a couple vavle reliefs.
390 in it's very first form had a stock piston.
Here's the evolution of those two engine programs:
300 and 380 initially came with a stock long block right from the Saltillo Mexico engine line. Both had stock magnum heads. 380 got the cam, springs and retainers changed....300 did not.
Then MP ran Chrysler completely out of OE magnum heads, the OE supplier wasn't interested in making them anymore, and it probably would have cost 500k or more to modify the tools to fit a different foundry line.....So, enter the R/T heads and plan B:
320 and 390 had R/T heads and started out with stock Saltillo shortblocks.
That worked fine for awhile, but it wasn't long before MP ran Chrysler completely out of new OE shortblocks...and it was time for plan C:
They both got .020 over reman shortblocks with FM hypereutectic pistons, R/T heads, and otherwise the same specs as before.
380 had a stock piston.
390 in it's final, .020 over form had a better piston with a couple vavle reliefs.
390 in it's very first form had a stock piston.
Posted By: JeepJimmy
Re: 300hp magnum crate 360 convert to 380hp? - 03/29/10 10:13 PM
Thanks Zippy, i could not get a correct answer from anyone. trying to find a PN breakdown of the motors. i know i saw one years ago.. Wonder how it will work keeping the dual plane. its not a drag car.
Posted By: Noblewk
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 12:00 AM
Quote:
Change the cam, springs, retainers, and intake and you're done.
Here's the evolution of those two engine programs:
300 and 380 initially came with a stock long block right from the Saltillo Mexico engine line. Both had stock magnum heads. 380 got the cam, springs and retainers changed....300 did not.
Then MP ran Chrysler completely out of OE magnum heads, the OE supplier wasn't interested in making them anymore, and it probably would have cost 500k or more to modify the tools to fit a different foundry line.....So, enter the R/T heads and plan B:
320 and 390 had R/T heads and started out with stock Saltillo shortblocks.
That worked fine for awhile, but it wasn't long before MP ran Chrysler completely out of new OE shortblocks...and it was time for plan C:
They both got .020 over reman shortblocks with FM hypereutectic pistons, R/T heads, and otherwise the same specs as before.
380 had a stock piston.
390 in it's final, .020 over form had a better piston with a couple vavle reliefs.
390 in it's very first form had a stock piston.
Plan D. While making the 402 stroker the R/T heads were adapted to "Big valve" heads. The remainer of the R/T "Big Valve" heads were used in the last production run. All crates were put together my Cummins. You will find a Cummins Date tag/Serial# on the blocks "pass side on the Bell mount"
Posted By: HotRodDave
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 01:11 AM
Quote:Quote:
The pistons are different and slightly higher compression, the 380 HP motor I saw come appart had pistons with 2 valve releifs instead of the soap dish production pistons and 300hp pistons. They were below deck but I don't know how much but they would give a slightly higher compression. [/quote
Thanks for the aditional insight there, very helpful
Posted By: BigDawg72
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 01:48 AM
Zippy... Thanks for a very informative post!
To the OP, I am using the Professional Products Airgap RPM knockoff in my build and was told by someone knowledgeable on the magnum engines that it should produce more HP than the Mopar M1 single plane intake. They stated that the M1 wasn't a great intake.
If my Flamethrower distributor would hurry up and get here I would fire mine up and have some real feedback on the combo. It does make me feel confident that my 400-425 HP goal is attainable since the same cam was/is used on the 380, 390, and 435 horse crate engines. I know it's all in the heads, but I hope to see the high side of 400 with my slightly cleaned up plain magnums. Maybe I' m too optimistic...
To the OP, I am using the Professional Products Airgap RPM knockoff in my build and was told by someone knowledgeable on the magnum engines that it should produce more HP than the Mopar M1 single plane intake. They stated that the M1 wasn't a great intake.
If my Flamethrower distributor would hurry up and get here I would fire mine up and have some real feedback on the combo. It does make me feel confident that my 400-425 HP goal is attainable since the same cam was/is used on the 380, 390, and 435 horse crate engines. I know it's all in the heads, but I hope to see the high side of 400 with my slightly cleaned up plain magnums. Maybe I' m too optimistic...
Posted By: PAINT IT BLACK
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 03:19 AM
I'll confirm that my 380 horse Magnum didn't have the R/T heads. I reused the block when I stroked the motor after it spun a bearing on me... sold the heads on ebay in favor of Eddys.
Posted By: goldmember
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 03:52 AM
Quote:Quote:I was picturing you looking at the valve reliefs and doing the math in your head,then the distance down by eyeball and more speculating. Thats real helpful!Quote:
The pistons are different and slightly higher compression, the 380 HP motor I saw come appart had pistons with 2 valve releifs instead of the soap dish production pistons and 300hp pistons. They were below deck but I don't know how much but they would give a slightly higher compression. [/quote
Thanks for the aditional insight there, very helpful
Posted By: patrick
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 11:03 AM
upgrading a 300HP mag motor for a street car, I think I'd use a cam like a hughes 1828, not something as big duration wise as the 380 horse motor. Zippy, I thought the 300HP motors got the upgraded springs, too.
the dual plane isn't a bad piece, it's on par with a stock LA 4bbl intake. an edelbrock air gap would probably be worth an additional 15-20 HP...
the M1 single plane is a good intake, probably makes about the same or a touch more HP as the air gap, but like most single planes, is probably down 15-20 lb ft of midrange torque over the air gap or the dual plane....
the dual plane isn't a bad piece, it's on par with a stock LA 4bbl intake. an edelbrock air gap would probably be worth an additional 15-20 HP...
the M1 single plane is a good intake, probably makes about the same or a touch more HP as the air gap, but like most single planes, is probably down 15-20 lb ft of midrange torque over the air gap or the dual plane....
Posted By: Alikazam
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 12:59 PM
Quote:
Zippy... Thanks for a very informative post!
To the OP, I am using the Professional Products Airgap RPM knockoff in my build and was told by someone knowledgeable on the magnum engines that it should produce more HP than the Mopar M1 single plane intake. They stated that the M1 wasn't a great intake.
If my Flamethrower distributor would hurry up and get here I would fire mine up and have some real feedback on the combo. It does make me feel confident that my 400-425 HP goal is attainable since the same cam was/is used on the 380, 390, and 435 horse crate engines. I know it's all in the heads, but I hope to see the high side of 400 with my slightly cleaned up plain magnums. Maybe I' m too optimistic...
My 360 is putting down 340 whp on a dynojet chassis dyno, so with 20% drive train loss comes right at 425 hp (727 transmission, ford 9" rearend). I run Edelbrock heads (not ported, out of the box), RPM Air-Gap, 10.2:1 compression ratio, holley 750 VS carb, headers and dual 2.5" exhaust, and a crane retro-fit roller cam (112 lsa, 107 installed, 230/238 @ .050, .528/.538 lift). If your combo is close to this you should be able to see similar numbers I'd think
Posted By: ZIPPY
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 01:57 PM
The 402 really didn't enter into the conversation but since someone mentioned it, it was not really a plan D relative to the 360-380/390. It was sold at the same time the 390 was available.
There is a new low cost 4" stroke, reman-style, magnum head MP crate engine hopefully coming online this summer. I'm not going to post the part number until it's been activated, however the directional MSRP is currently $5419 so that's a good sign. Given the pieces in it, it should run as hard (or better) than the older version.
On the intake....for a 3.58 stroke combination using a dual plane instead of a single plane really isn't a huge handicap, depending on the car. Usually the dual plane will outrun the single plane on a street oriented 3.55 gear, 2400 stall type of car.
There is a new low cost 4" stroke, reman-style, magnum head MP crate engine hopefully coming online this summer. I'm not going to post the part number until it's been activated, however the directional MSRP is currently $5419 so that's a good sign. Given the pieces in it, it should run as hard (or better) than the older version.
On the intake....for a 3.58 stroke combination using a dual plane instead of a single plane really isn't a huge handicap, depending on the car. Usually the dual plane will outrun the single plane on a street oriented 3.55 gear, 2400 stall type of car.
Posted By: Noblewk
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 02:10 PM
The plan D had to do with the "Big Valve" R/T heads on the last group of 360/390 crates. The earlier versions of the combo received the standard R/T head combination.
Posted By: ZIPPY
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 02:32 PM
True, point taken and that's correct.
Posted By: Venomvpr900
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 04:29 PM
Quote:
There is a new low cost 4" stroke, reman-style, magnum head MP crate engine hopefully coming online this summer. I'm not going to post the part number until it's been activated, however the directional MSRP is currently $5419 so that's a good sign. Given the pieces in it, it should run as hard (or better) than the older version.
That would be better then the $10,000 they have the 405hp 360 listed for. What a rip
Posted By: Mr.Yuck
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 05:26 PM
cam, intake and headers I think.
Posted By: ZIPPY
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 06:04 PM
Quote:Quote:
There is a new low cost 4" stroke, reman-style, magnum head MP crate engine hopefully coming online this summer. I'm not going to post the part number until it's been activated, however the directional MSRP is currently $5419 so that's a good sign. Given the pieces in it, it should run as hard (or better) than the older version.
That would be better then the $10,000 they have the 405hp 360 listed for. What a rip
The race block, aluminum heads, forged crank/rods/pistons, and race quality build/dyno facility (none of which are really "required" for a 405hp motor but that's debateable) drove the price way up there, there's no doubt about it.
Posted By: JeepJimmy
Re: 300hp magnum crate 360 convert to 380hp? - 03/30/10 11:04 PM
i found a old 02 MP catalog. says both motors used the P5249464 valve springs. so i guess i dont have to change them??? 
now im confused
now im confused
Posted By: ZIPPY
Re: 300hp magnum crate 360 convert to 380hp? - 03/31/10 03:39 AM
Though the older marketing says otherwise...in practice, I've seen and heard of them both ways. Sorry, just passing it along.
Though Mopar specified the parts and marketed the engine...the better springs were not really required for the 300 to run well, and Cummins was known to deviate from the bill of materials at times.
Pull one spring and pressure check it, compare to the recommended spring and go forward
Though Mopar specified the parts and marketed the engine...the better springs were not really required for the 300 to run well, and Cummins was known to deviate from the bill of materials at times.
Pull one spring and pressure check it, compare to the recommended spring and go forward
Posted By: HotRodDave
Re: 300hp magnum crate 360 convert to 380hp? - 03/31/10 03:45 AM
This just got me thinking and so I called up my friend with the crate motor that is supposed to be a 380 he said it does have the R/T heads so I informed him it is a 390 hp motor. Also he measured the pistons for me and they are .069 down and I measured a stock 5.9 here at my house and the pistons are .071 down and I can promise you the soapdish in my pistons are bigger than the 2 valve releifs in his pistons but he don't have a CC measureing device so I can not give you a number.
Also not that it matters to this discussion very much but the valve springs on his heads are cylinderical not behive.
Also not that it matters to this discussion very much but the valve springs on his heads are cylinderical not behive.
Posted By: Venomvpr900
Re: 300hp magnum crate 360 convert to 380hp? - 03/31/10 02:50 PM
Heres the specs on mine?
Specifications:
• Thermocycled Block Is Bored to +0.020" Oversize
• New Magnum R/T Big Valve Cylinder Heads
• Mopar Cast Aluminum Valve Covers
• High-Strength Stainless Steel Valves — 2.02" Intake, 1.62" Exhaust
• Heavy-Duty Valve Springs
• Hydraulic Roller Camshaft — 288°/292° Advertised Duration (230°/234° Duration @ .050") 0.501"/0.513" Lift
• Pistons — 9.0:1 C.R.
• Single Plane, M1® 4-bbl Aluminum Intake Manifold
• (Includes Bosses for MPI Conversion; Taller than Stock — Check Hood Clearance)
• Double Roller Timing Chain and Sprocket
• Mopar Performance Electronic Ignition Kit with Distributor
• High Volume Oil Pump
I now know that "Thermocycled" is mopars marketing term for reman 
I have no complaints with the product I received. It runs great and has every bit of 390 hp
I do question how the new improved version with the race block, aluminum heads, 10:1 compression ratio, forged everything, and the tuning and dyno testing can only make 15hp more for $10,000 I would think I could take my other stock r/t block and build a 500+ horse small block
Specifications:
• Thermocycled Block Is Bored to +0.020" Oversize
• New Magnum R/T Big Valve Cylinder Heads
• Mopar Cast Aluminum Valve Covers
• High-Strength Stainless Steel Valves — 2.02" Intake, 1.62" Exhaust
• Heavy-Duty Valve Springs
• Hydraulic Roller Camshaft — 288°/292° Advertised Duration (230°/234° Duration @ .050") 0.501"/0.513" Lift
• Pistons — 9.0:1 C.R.
• Single Plane, M1® 4-bbl Aluminum Intake Manifold
• (Includes Bosses for MPI Conversion; Taller than Stock — Check Hood Clearance)
• Double Roller Timing Chain and Sprocket
• Mopar Performance Electronic Ignition Kit with Distributor
• High Volume Oil Pump
I now know that "Thermocycled"
is mopars marketing term for reman I have no complaints with the product I received. It runs great and has every bit of 390 hp
I do question how the new improved version with the race block, aluminum heads, 10:1 compression ratio, forged everything, and the tuning and dyno testing can only make 15hp more for $10,000 I would think I could take my other stock r/t block and build a 500+ horse small block
Posted By: patrick
Re: 300hp magnum crate 360 convert to 380hp? - 03/31/10 04:27 PM
Quote:
Though the older marketing says otherwise...in practice, I've seen and heard of them both ways. Sorry, just passing it along.
Though Mopar specified the parts and marketed the engine...the better springs were not really required for the 300 to run well, and Cummins was known to deviate from the bill of materials at times.
Pull one spring and pressure check it, compare to the recommended spring and go forward
easier visual reference is the MP .525" springs the crates are supposed to have are 1.4" OD straight springs, the stock mag springs are behives with a ~1.1" OD retainer...
Posted By: patrick
Re: 300hp magnum crate 360 convert to 380hp? - 03/31/10 04:38 PM
Quote:
Heres the specs on mine?
Specifications:
• Thermocycled Block Is Bored to +0.020" Oversize
• New Magnum R/T Big Valve Cylinder Heads
• Mopar Cast Aluminum Valve Covers
• High-Strength Stainless Steel Valves — 2.02" Intake, 1.62" Exhaust
• Heavy-Duty Valve Springs
• Hydraulic Roller Camshaft — 288°/292° Advertised Duration (230°/234° Duration @ .050") 0.501"/0.513" Lift
• Pistons — 9.0:1 C.R.
• Single Plane, M1® 4-bbl Aluminum Intake Manifold
• (Includes Bosses for MPI Conversion; Taller than Stock — Check Hood Clearance)
• Double Roller Timing Chain and Sprocket
• Mopar Performance Electronic Ignition Kit with Distributor
• High Volume Oil Pump
I now know that "Thermocycled"
I have no complaints with the product I received. It runs great and has every bit of 390 hp
simple, the MP aluminum mag heads shroud the valves really bad in stock config, flow about the same as untouched R/T's....no additional flow makes no additional power.
the additional point of compression should yield 3-4% more power, or 12-16 more HP on a 400 HP motor...
Posted By: ZIPPY
Re: 300hp magnum crate 360 convert to 380hp? - 03/31/10 05:03 PM
Quote:Quote:
Heres the specs on mine?
Specifications:
• Thermocycled Block Is Bored to +0.020" Oversize
• New Magnum R/T Big Valve Cylinder Heads
• Mopar Cast Aluminum Valve Covers
• High-Strength Stainless Steel Valves — 2.02" Intake, 1.62" Exhaust
• Heavy-Duty Valve Springs
• Hydraulic Roller Camshaft — 288°/292° Advertised Duration (230°/234° Duration @ .050") 0.501"/0.513" Lift
• Pistons — 9.0:1 C.R.
• Single Plane, M1® 4-bbl Aluminum Intake Manifold
• (Includes Bosses for MPI Conversion; Taller than Stock — Check Hood Clearance)
• Double Roller Timing Chain and Sprocket
• Mopar Performance Electronic Ignition Kit with Distributor
• High Volume Oil Pump
I now know that "Thermocycled"
I have no complaints with the product I received. It runs great and has every bit of 390 hp
simple, the MP aluminum mag heads shroud the valves really bad in stock config, flow about the same as untouched R/T's....no additional flow makes no additional power.
That might be true if the newer crate engines used the older MP aluminum magnum heads in the old configuration, but unfortunately they don't. They now use an Edelbrock magnum head with a MP logo on it.
Unfortunately HP ratings are conservative marketing, not actual data.
An average 380 really made about 408, an average 390 really made about 410, and so on....I have no idea about the new one.....other than it should be better than it's rated at, given the E heads that are on it.
If you're very resourceful and very patient, you can make
7, 800HP or more for 10 grand. Small block crate engines aren't marketed towards the kind of person who would spend years waiting for good deals on parts, who would spend many hours massaging everything, etc.
Posted By: patrick
Re: 300hp magnum crate 360 convert to 380hp? - 04/01/10 12:05 PM
I didn't realize they have moved to an eddy based heads vs. the small port commando based aluminum magnum heads....
yeah, that 405 horse is probably a real world 420-430 with eddie heads...
yeah, that 405 horse is probably a real world 420-430 with eddie heads...