[QUOTE=RalphP;3341402]Heh.

First source of info would be Hughes Engines, and then Mancini Racing, IMO.

However, I've not seen a high rise intake for the 3.9 .

The pistons are no problem; you can use any 318/5.2 piston / rod / valve parts save for the camshaft. ok gonna see how much its gonna cost to put 3i8 parts in the engine as you said pistons, rods, valves, put a mild cam on it that gives me a good lope, put alluminum heads and run it up to 12:1. Question is is there a 4bbl set up i can put on it or can i use the carb off the 318 and run another manifold for that carb? and what cam can i put in it?

 

If you're just a little adventurous, you could drop a later model Magnum V6 in. You'd get an extra 55 horses from a motor that'll bolt right in, fan and all. The "adventure" part would be that you'd have to grab the Magnum computer and engine bay wire harness, the fuel tank w/pump, the flywheel, and you'd need to put a notch in your bellhousing for the crank sensor.

The result: about 10 more horse power than a stock LA 318, less weight up front, and a multi-point EFI motor that'll give you decent mpg. Add headers and a CAI and increase the fun. Crazy idea right?

 

I'm keeping it carbed, I been going back and forth on rebuld 3.9 or v8. I think we gonna use v8 is too nice not to use too many performance parts. Gonna use original trans just beef it up. Will have to use diff mounts. I know I want to keep org grill and headlights might need smaller brake booster to put engine back further. That or use different waterpump.

 

Quote:

Originally Posted by new_red87

I'm keeping it carbed, I been going back and forth on rebuld 3.9 or v8. I think we gonna use v8 is too nice not to use too many performance parts. Gonna use original trans just beef it up. Will have to use diff mounts. I know I want to keep org grill and headlights might need smaller brake booster to put engine back further. That or use different waterpump.

Take a hard look at moving the motor mounts on a 4wd before you commit to that motor. The mounts tie the front differential to the truck. There is a brace on each side of the motor that goes from the motor down to the differential and back to the transmission. If you move the motor, you are going to have to rework those braces somehow.
Also, if you move the motor back, you will need to move the cross member as well and probably shorten the rear driveshaft and have a longer front driveshaft made.

I know I am beating a dead horse here, but if you use a magnum motor, it will bolt up to your existing motor mounts and the serpentine belt system will clear the radiator.
You can reuse your existing flex plate on the magnum motor
You would need a magnum carbed intake (edelbrock 7577) a sbm distributor, and a carb. With the factory manifolds, you can run a standard dakota y-pipe from a magnum truck. It will all bolt together and with miminal wiring to be done.


As far as building the existing 3.9, here is what I found as problems.
1. no one makes a distributor to replace the one in the truck now. The factory dist. runs with the computer and is not a standalone distributor. Years ago, mopar made one, but its long since been discontinued.
2. No one makes an aftermarket intake manifold.
3. cams, you may find, or at least a regrind.
4. factory heads could be reworked to a degree, but no aftermarket available.

The V8 has many more parts available and there is no replacement for displacement!!


One other thing, ANYONE who suggest running 12 to 1 compression on a street motor, (assuming 93 or less octane fuel) has no idea what they are talking about, especially with a carb, and conventional distributor.

 

93 ragtop broke it down well regarding the advantages of using the Magnum motor. His point on trying to modify motor mounting position is very valid in regard to a 4X4.

I suggest giving serious thought to what you want from this project; a fast 4X4, a reliable 4X4, good mpg, easy swap, lower cost, etc. and then decide which are most important. We're pretty good at answering questions under those topics. Want to know which swap is easiest, we can tell you. Want to know which swap will give you the best power for the least investment, we can help. If a SB Chevy in your ride fits the requirements, you'll get great opinions on that too

 

Wouldn't I have to change the magnum v8 to carbed if I did that? And by small block chevy u mean 350?

 

If you want it carbed, you'd have to swap on a Magnum manifold that accepts a carb, or possibly re-drill the angled holes in an LA manifold (I understand its possible anyway). The Magnum swap has been done a lot by folks who want a somewhat more modern motor in their older Mopar vehicles. The Magnum is a drop-in, pretty much wherever the LA motor was it will bolt right up; and swapping on a carb and manifold is relatively easy given the benefits the newer motor brings. Magnum heads have advantages over LA heads; lighter valves, better port flow, improved combustion chamber design (and I forget what else at the moment, sorry). Horsepower on the old LA 318 jumped from about 170 up to 235 when the Magnum version (5.2) came out in '92.

The SB Chevy option could be any number of displacements, but yes, most of us probably think 350. No shortage of cheap performance parts available in that arena.

 

Here is a link to a manifold. http://www.ebay.com/itm/Edelbrock-75...pYQrj8&vxp=mtr

You can use the same distributor that you were going to use with the 318 la motor. Assuming you were going to use a 4bbl carb with the LA it should work on the edelbrock intake.

 

You may also have some fuel line work if you go with a carbed magnum....you'll need a pressure regulator assuming you are using the in tank electric fuel pump. You have a return fuel system so you'll need the 3 way holley regulator. Your magnum from a junker won't have a mechanical fuel pump cam. Not sure what fuel setup you have now on your 87...if it was already carbed you may be already set up...not too familiar with 87 but I recall it was pretty different fuel wise vs 88 and on.

 

Quote:

Originally Posted by robertmee

You may also have some fuel line work if you go with a carbed magnum....you'll need a pressure regulator assuming you are using the in tank electric fuel pump. You have a return fuel system so you'll need the 3 way holley regulator. Your magnum from a junker won't have a mechanical fuel pump cam. Not sure what fuel setup you have now on your 87...if it was already carbed you may be already set up...not too familiar with 87 but I recall it was pretty different fuel wise vs 88 and on.

Your right, I forgot the fuel pump The 87 has a mechanical pump. I already converted mine to an electric. But I just used a carter 4070. Its single line and does not require a regulator. http://www.jegs.com/i/Carter/180/P4070/10002/-1


BTW The 318 magnum is rated at 225-230 net hp. Id bet that if you could compare it to the older gross hp ratings, it would be closer to 275-300 hp rating.