I should not have provoked an argument. My bad.

I'm sorry,no need to feel bad. Lot's of things are possible and I've tried alot along the years but when giving advise to someone I would rather give advice that works 100% of the time than info that has much less chance of success. If this combo was for a 3000lb car I might suggest something different.For fuel I'd guess the poster would like not to be locked into buying 91(or better) octane fuel,but thats a guess on my part. Again no offence intended.

we're good

I appreciate all of the input I have alot of different options to look at now. At the local pick a part yard I know thier are a couple Rams vans and dakotas with 318 magnum engines I dont remember seeing any 360's last time I was there. I have heard that they are prone to crack around the valve seats are there any other problem areas? I'm hoping to get down thier this week and see if there is anything worth taking. What is a fair price for a junk yard set of magnums?

I paid $350 for a complete 1999 5.9 Magnum from a Dakota R/T, in running condition. It has 80,000 miles, no sign of blowby, some coking on the inside, a full quantity of slippery dark oil in the pan, the full serpentine setup less A/C compressor and the magnum exhaust manifolds. I bought an airgap style polished intake used for $100. The rest of the package will come from the original LA 360 in the car and some new gaskets. That's my definition of on a budget. Hopefully it will be the equivolant of a 300 hp magnum crate when it's complete. Why pay for machining when it's still good?

New hemis are 10.5 compression 205 thermostats and run fine on 87 octane with very short duration cams and brittle pistons. Magnums have better chamber and being stuck on 91+ octane is not a big deal. More compression means more efficency and makes up the differance in price. I would shoot for 10 to 1 with magnums and that is conservative. The LD 340 runs out of steam at 6500 on a 340 and a touch less on a 360 if you had a regular performer you would shift the power down a tad but really not much. It will start makeing power around 2000 where even factory converters are just stalling any how. Get a small tube longest length you can find or some early magnum ex manifolds.

I just don't have a comeback for the logic in that!

Just as a point of reference to how good the magnum head is;

I have a LA360 block with KB107 pistons at zero deck, an 0.039" thick head gasket and magnum heads which cc'd at 64. This gives me a static compression ratio of 10.6:1. I am using a Comp XE268H cam (224/230 @ 0.050, .509/.512, 110). With this cam I have 180-195 psi of cranking pressure.

I run the engine on 89 octane and in a pinch I have used 87 but have to be careful getting on it below 3000 rpm.

The engine pulls strong from 1500 rpm and runs out of steam just over 6500 rpm and I cruise in 4th of an A833OD/3.55/27" combo at 1300-1400 rpm. It accelerates away smoothly and cleanly. Based on 1/4 mile trap speeds I am making about 370HP with this engine and Comps Cam quest estimates the power at 410 HP.

This is in a 68 Barracuda that weights about 3600 lbs with me in it.

For a torque monster one of the smaller Comp XE cams or euivalent Voodoos would be the hot ticket but they will raise the cranking pressure to. Maybe enough to warrant starting with a slightly lower static compression ratio. Keith Black has a step dish piston just for the magnum head that will allow you to maintain the tight quench of zero deck on the closed side of the chamber with a dish area under the plug and valves for lower compression.

I have a 10 to 1 318 with a factory 273 2bbl cam and it has a 195 t-stat 2.76 gears LU trans and it does not ping on 89 octane even under a load going up big mountain passes and a 6x12 enclosed trailer. With slightly bigger cam, 180 t-stat and better chambers than even my heads (302s) have he will be fine. I have a thermo quad carb set very lean and uncoated headers putting off a lot of under hood heat too boot and have knocked down a best of 29 mpg with this car. Higher compression equals higher engine efficency from thermal expansion rates being higher and higher compression gets more exhaust out to make a less diluted intake charge and by squeezing the mix tighter it burns faster (DUH) and will do more work on the piston instead of continueing to burn as it goes out the ex valve. This is the reasoning that you need to get through your thick skull. You will get higher miledge from higher compression assumeing you don't get the dome in the way of a fast complete burn, that is why flat top pistons are better than dishes or domes. And that is how higher efficency of the higher compression makes up the 20 cents differance in a gallon.

Here again the guy has the LD340. Why spend the money for another intake when this one will work fine. Sure it has a little higher RPM rating and performance but there is nothing wrong with its low end performance either.
As for in the first post the poster also states that he is thinking of putting on an Airgap in lieu of the LD340. No point in that, there is so little difference in performance (if any) that the swap out would be money down the drain.
Very probably get the best low end out of the OEM cast iron intake of the standard Performer which is not much more than an aluminum version of the cast manifold.

The point is it's the combo! It doesn't mean a thing that you could get away with something if everything falls into place,I know from experience,not reading a magazine and false assumtions. The poster is putting this in a truck! Not a much lighter A body. I don't think Spending the higher price for 91 octane is at all logical for the application. I built 360's with near 11 to 1 comp using magnum heads in the mid 90's and yes I agree they will tolerate slightly more comp I won't tell someone building for THIS APPLICATION that it's the smartest thing to do,Period.

If anyone has the skill to build carbon fiber intake manifolds please get it touch with me. I can design what I need but have no experience with the constrution of. Thanks

I've also been hanging out under the hood since 1969 and my comments aren't directed at you. Seems there are alot of good people on moparts trying to give good advice,again my message to the original poster is don't get caught up it out tricking yourself,this is easy to get right or easy to get a headache.

I think if your pushing over 160+ cranking cylinder pressure you may be pushing the limits for pump fuel on an older iron headed engine?

Lot's of factors come into the picture,the cranking number is just a part of the picture. I've run alot more with open chamber heads without issue,but without the whole picture I'd be wrong to tell everyone to run 190cranking and you'll never have a problem,or compare my combo to any late mode engine would be a real waste of peoples time. JMHO.

A stock 5.9 Magnum IS the 300 hp 360 crate motor. Check the part numbers. Cam, crank, heads, and everythign else is the same. Add your own intake and go.

Get a 5.9 Magnum. Add a carbed intake and electric fuel pump. Hit the road.

If you want a little more pulling power, you can swap to an RV type cam but that's optional.

If you really want torque, swap in a real 5.9 (read: Cummins) and drag all the gassers sideways.