Hypothetical - Cheap 360 Magnum Rebuild

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Logan Haun

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Gentlemen,

I recently purchased a 1971 duster from another Fabo member. With the duster came a disassembled 360 magnum engine. I would like to build the engine for at least 300 hp and for under $1750 if possible. I am going to run it with a 3.55 limited slip rear end and it will be street only. I was told the cylinders only need honed. The block has been hot tanked and cam bearings have been installed. The heads are complete. They were magnafluxed and no cracks were found. The following parts also came with the engine: Pistons, Windage tray, Piston rods, New double roller timing chain, holley 4 barrel 750 cfm carb, long tube headers, camshaft, lifters, rockers, push rods, timing chain cover, freeze plugs, harmonic balancer, and flex plate.

I figure, figuring all the parts are good, that I will buy at least the following:
New high volume oil pump
Hughes whiplash cam
Main Bearings
Gasket set
Crankshaft(junkyard find?)
Crosswind intake
Machining work?
Valve covers
New Valve springs and retainers for the magnum heads
Ignition
Water pump
Belts, pulleys, etc...

This is my first build ever so I am reaching out for some direction that way I do it right.

Thanks

- Logan
 
Def can be done for under $1750.
My crank just needed a polish, and I had a regrind done on the cam for cheap. If you can find a good JY crank and cam, you'll save some coin. Oil pan?
 
Oh yeah, It did come with a mid sump oil pan and pick up - thanks for reminding me. What do you think the chances are of me pulling a decent crank from the junkyard?
 
Build it back stock. There's your 300 HP.
 
If you have the stock lifters, then IMO add a cam ($330 or so) and valve springs ($100 or so) and light a little fire under the hat.

A very mello grind can add 30 hp and drive like it was stock. A cam duration under [email protected] will not require a stall converter. A cam under [email protected] will operate super close to dead stock. It would be excellent with the 3.55's.

Been there doing that now. And in a heavier '79 B body.

Save your pennies
 
rumblefish360 said:
If you have the stock lifters, then IMO add a cam ($330 or so) and valve springs ($100 or so) and light a little fire under the hat.

A very mello grind can add 30 hp and drive like it was stock. A cam duration under [email protected] will not require a stall converter. A cam under [email protected] will operate super close to dead stock. It would be excellent with the 3.55's.

Been there doing that now. And in a heavier '79 B body.

Save your pennies
Click to expand...
Speaking of,Robert....how's ,the gas mileage?.
 
rumblefish360 said:
If you have the stock lifters, then IMO add a cam ($330 or so) and valve springs ($100 or so) and light a little fire under the hat.

A very mello grind can add 30 hp and drive like it was stock. A cam duration under [email protected] will not require a stall converter. A cam under [email protected] will operate super close to dead stock. It would be excellent with the 3.55's.

Been there doing that now. And in a heavier '79 B body.

Save your pennies
Click to expand...
An excellent statement,here.....
 
Abodybomber said:
Speaking of,Robert....how's ,the gas mileage?.
Click to expand...
I've been plagued with multiple problems with the car. I had it out a total of 3 times this entire year. (Grooooooan & BOOOOO!)

What I have noticed but not recorded is only a guess at this time but I'm thinking maybe 15 mpg's at 70 mph with the 355's and a 245/60/15. It is reasonable around town. Hwy. driving at 70 sucks it down a good bit. Broken tach. (Grrrrrr!)

Trans is a freshly rebuilt (again!) 727 w/a 2200 stall.
The rest of the engine (for everyone else) is a 5.9,'00 magnum with hooker super comps at 1-3/4 into 2-1/2 exhaust. (Which as been an issue.)
An RPM & 650 Thunder AVS triggered by a MP chrome box. (Distributor is an issue.) '72-340 air cleaner up top.
Stock cam.

It does take off good. Not so easy to spin the wheels though. (Timing issues at the distributor)

There was a mishap at the transmission shops garage. The car was up in the air and the lift had a failure dropping the car. There was an "object" under it denting, Er, I ment, destroying the gas tank. A FBBO member to the rescue!

Just two days ago I replaced the transmission lines.
Exhaust parts on the way.
I also have to take out the seats and fix the mounting area for the drivers seat. It needs some metal and a welder.
Then I get to play electrician again.
Nothing light tail lights working, then not working, then working.....

Someday... I'd like to get a cam.
(And actually have time to put it in!)

I'd like to sell the car.
I just have to much.
 
Hey Ted, whats up?

You knowthis is a Magnum engine right? Just a mentioning....

Hows that Duster doing?
 
Thank you all for the prompt replies,

As for a cam, hughes engines will regrind my stock cam for $100 after the core charge refund. The cam, after regrind, would have the following duration @.050
Intake - 208
Exhaust - 214
They also quoted me for new valve springs, retainers, and locks. So a reground cam from hughes and the spring upgrade would cost me roughly $303
 
Logan Haun said:
Thank you all for the prompt replies,

As for a cam, hughes engines will regrind my stock cam for $100 after the core charge refund. The cam, after regrind, would have the following duration @.050
Intake - 208
Exhaust - 214
They also quoted me for new valve springs, retainers, and locks. So a reground cam from hughes and the spring upgrade would cost me roughly $303
Click to expand...

Sounds about right.
I think it was about 325 for mine with about the same , and that was a regrind Magnum snout roller cam 214/224 and a 110 LSA.
I was even able to run the stock Mag pushrods, which surprised me.
 
I see you were using a melling high volume oil pump, I saw on magnum swap they said not to? Anyone have more info on this, also, something about the shaft on the pump is an issue?
 
Dont put a high volume pump in it, use a good brand of stock pump and you will have 20 at idle and 50 above 1500. A LA 360 crank is the same as the 5.9 magnum crank...
There is a better cam grind out there, more on intake and less on exhaust.
If you put it back together with a good cam you will have 300-325 HP.
 
Remember too, when throwing horse power figures around that most people in the hot rod community speak in GROSS horse power terms, not net.

The stock 5.9 Magnum easily has 300 gross horse power. Possibly more. I agree about there being better grinds for a cam.
 
RustyRatRod said:
Remember too, when throwing horse power figures around that most people in the hot rod community speak in GROSS horse power terms, not net.

The stock 5.9 Magnum easily has 300 gross horse power. Possibly more. I agree about there being better grinds for a cam.
Click to expand...
Yes. On a dyno, I watched one with headers, 650 carb, airgap mani make like 235.
 
Big diff between CHASIS dyno and ENGINE dyno. 300-325 at the crank(ENGINE dyno) is easy with just a cam swap. 235 would be chassis dyno with standard drive train loss with a stock 5.9 turd stick or a very ill 5.9 on an engine dyno.
 
So, im trying to reach 300 net hp at the flywheel. Thats only 55 hp over the stock 5.9 magnum. If I build the engine back to stock with the modifications being a reground cam, headers, intake, carb, windage tray, and valve spring upgrade I think I will achieve 300. The car doesnt have ac or power steering. I was planning on getting my rebuild parts from summit racing. Yay? Nay?

Thanks for the help,

- Logan
 
Logan Haun said:
So, im trying to reach 300 net hp at the flywheel. Thats only 55 hp over the stock 5.9 magnum. If I build the engine back to stock with the modifications being a reground cam, headers, intake, carb, windage tray, and valve spring upgrade. I was planning on getting my rebuild parts from summit racing. Yay?

Thanks for the help,

- Logan
Click to expand...
Dang. I was gonna ask about windage trays. I just ordered a new LA pan, and noticed I didn't see a tray...
 
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