..........power expectations........

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oldkimmer

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..................I have a 1975 duster with 40,000 original miles, factory 360 4bbl, 727 with factory hi stall converter, 3.21 sure grip and dual exhaust......would I expect much of a power increase from just putting in a factory stock 1998 360 magnum from a truck ..........thanks......kim.......
 
Yeah I would certainly think so.
 
Yes, in stock form the Mag makes more power.
With the LA you have its only lacking compression, change pistons and be done with it

Keep in mind the balance is different between the magnum and the la, so more money to spend.
 
The Magnum also has "supposedly" better heads and the roller cam too.
 
True, but he will also need a conversion kit for the cam to run a mechanical fuel pump, and if there is headers on his car, grind the truck mounts off the block.

Also the mag I have, the heads were cracked, but still usable.
I gave them to a friend who bolted them on his truck and he had no issues.

I would go over to magnumswaps web site and read everything, lots of good info.
 
Why not get a set of 273/318 heads and have either 1.88" or 2.02" intakes and 1.6" exhaust valves in them and port them...

Then you will increase the compression about a point without having to change pistons.

Then upgrade the cam.

Why throw away a good 360....
 
krazykuda said:
Why not get a set of 273/318 heads and have either 1.88" or 2.02" intakes and 1.6" exhaust valves in them and port them...

Then you will increase the compression about a point without having to change pistons.

Then upgrade the cam.

Why throw away a good 360....
Click to expand...

Are you saving the original 360,for future use Kimmer? I still like the Magnum., bolt & play.

FWIW : the basic year Magnum you have: is the 300 horsepower M/P crate mill. Same damn long block, add a carbed intake.
 
RustyRatRod said:
The Magnum also has "supposedly" better heads and the roller cam too.
Click to expand...

Better low lift, those X castings outwick them,in overall flow ,Rob. Nice to have a buddy with unported head flow numbers,from the day.
 
Well those pollution era 360s were factory rated at 240hpNet, and Supposedly never even made that. Whereas even the 318 Magnums were rated, Net, at 230, and did make the numbers. I imagine the Magnum 360 would be quite an improvement. By direct inference the 360Magnum should be a minimum of 260Net. But if it is a 300 crank hp crate, the equivalent net hp might be a little more
But the really nice thing about the Magnums is the abundance of low speed torque, and they have loads more potential.I wouldn't hesitate for a moment to make the swap. Just be sure to correctly mothball that low-mileage LA. Someday you might be wanting to sell that Duster, or pass it on to a family member, and then a numbers matching engine will be worth something.
 
IMO, if we assume the car has power steering and alternator I think the 360 Magnum would net out closer to 240 when the '74 components were bolted to it. The Magnum accessories are a slightly lower draw and the mechanical fuel pump will factor in too. I think I would work with what was in there unless it's got issues. A simple bolt in cam, better exhaust, and performance tuning can make an easy 20-30hp and tq more with no other changes with much less effort.
 
Why not keep it all original? If the engines tight and doesn't have blow by throught the rings I would consider a good three angle valve job, and clean up the bowls a bit, maybe mill the heads .020 to .030 and some thin head gaskets. Headers alone will give you 20+ HP. Then a small voodoo 262 type cam.
 
..................OK guys, my daughter ran it at the track for 2 weekends.....ran the best of 16.19 @ 88.9 mph which I think is close to the factory times for it........no issues with the motor at all but its too slow would like to help it out to low 14s or high 13s...I do have headers, 3100-3600 stall, and I could put in an 8.75 with better gearing...I have 3.55, 3.91 and 4.30s........I unplugged the vac line and pulled the timing ahead which helped 2 tenths...............kim.......I also have a set of 302 heads and could get an alum intake......I cant remember what it weighed but I thought it was alot
 
Looks like you will need about another 100 HP at the crank to get to that ET range....is the car on the heavy side?
 
go with the magnum 360, mild cam, old style timing cover and aluminum intake.....you will be supprised how good it will run. Forget all the headswap nonsense on your factory motor. Put that engine to the side compleat and SAVE it...There are guys on here running into the 12s "I think" on junkyard 360 magnum longblocks.
 
You don't need 100hp more on a como that's less about stock economy and emissions and more abouty optimizing for performance.
1. Change the gearing.
2. Change (upgrade) the ignition.
3. Change the exhaust from the manifolds back to something low restriction and at least 2 1/4"ID from manifolds to tips.
4. Tune the carb (or replace it with something new and more tunable)

I don't think you even have to crack it open to get into the 14s. If you want faster -
5. Replace the manifolds with headers.
6. Replace the factory cam with a performance grind that takes the single spring with dampener (Comp 901-16s) and is in the 218-220° @ .050 range.
Those with the above will get you into the 13s with the right gears and properly tuned.
 
The Magnum engine is more then likely in pretty good shape on the inside. Build it on the side. Swap over the old style parts like A/J said and cam it. Stick with the roller. The cam is expensive, but, the swap over to a Hyd. or mechanical cam is nearly as pricey if not more. Since you have to get new pushrods at the proper length along with the cam and lifter set. It starts adding up.

If you all ready have LA intakes, you can have the Magnum heads textiles for them and save money over getting a Magnum intake.

Remember the create engine. It is a basic factory stock long block with performance parts.
Cam, intake and headers reaped a 360/380. These always dynoed over 400hp from many sources. Add 3.91's or better. The roller cam used was in the 230@.050 intake duration.

I have met a few fellas running them into the low 12's. 1 guy had a race weight (AKA- stripped down naked light weight Duster) running in the 11's.) 13's should not be a problem in a full weight car.
 
rumblefish360 said:
The Magnum engine is more then likely in pretty good shape on the inside. Build it on the side. Swap over the old style parts like A/J said and cam it. Stick with the roller. The cam is expensive, but, the swap over to a Hyd. or mechanical cam is nearly as pricey if not more. Since you have to get new pushrods at the proper length along with the cam and lifter set. It starts adding up.

If you all ready have LA intakes, you can have the Magnum heads textiles for them and save money over getting a Magnum intake.

Remember the create engine. It is a basic factory stock long block with performance parts.
Cam, intake and headers reaped a 360/380. These always dynoed over 400hp from many sources. Add 3.91's or better. The roller cam used was in the 230@.050 intake duration.

I have met a few fellas running them into the low 12's. 1 guy had a race weight (AKA- stripped down naked light weight Duster) running in the 11's.) 13's should not be a problem in a full weight car.
Click to expand...

DusterDoug,Walker434,& JoeDust451 come to mind... JoeDust451's combo is super mild, ran mid 12's Kimmer...FABO member thread,of mildly worked Magnum mills...

http://www.forabodiesonly.com/mopar/showthread.php?t=285660
 
Why not just slap some EQ'S on your 360 since that's the main difference and add a mild cam for a little extra punch.
 
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