Is a 360 EFI out of a Dakota the same as out of a car

[David B]

I have restomoded my 1970 non-numbers matching Barracuda. I use it as a daily driver as well as road trips. It has been to Alaska, Canada, Florida, Vermont, California and all the places in between. The Auto Hut oil pressure gauge reads about 30 psi while driving but less than 5 psi when at idle. Sometimes the the idiot light come on when idling in hot weather. I have no issues with the engine other than the oil pressure. I starts and runs great. I was considering replacing the 340 4-barrel with a 360 EFI from a Dakota. I do not know whether the Dakota engine and EFI system is the same as the ones in a car, ie 2-brl or 4-brl intake manifold, motor mts, or other differences that I haven't thought of. The 4 speed manual xmission has already been replaced with a 5 speed Tremec. The car originally had a 318 that was replaced by a 340 sometime before I bought it. The odometer had 52,000 miles but I don't believe it was accurate. I replaced the speedometer 9,000 miles ago.

 

[gzig5]

Truck oil pan is different but can be changed. Add a Magnum pilot bearing on the rear of the crank. You'd need a different computer to control the EFI on the truck motor, I don't think the truck computer works in stand alone mode. Easiest way would be to put a new intake on the truck motor and add a Sniper or FITech fuel injection. Not much besides that other than ignition. FABO has a dedicated Magnum swap section that probably has all the info you need.

 

[Scoots]

You'll need a lot. 45psi multi port injection pump (recommended in tank, new tank), fuel lines to handle it. Cutout in bell housing for the flywheel sensor, Mag is serpentine belt not V. Mag heads have an extra boss for acc to mount and much more.. it has been done many times its just not near plug and play.

 

[Scoots]

Oh an as mentioned above, a lot of PCM wiring and interface including O2 sensor. Again, as gzig5 said, a pre built kist like Holley, Fast, Edelbrock etc will save you dozens and dozens of man hours. Btw, it should take a weekend to pull your 340 and do an oil pump and main bearings. Then add the new EFI kit to that!

 

[gzig5]

You'll need a lot. 45psi multi port injection pump (recommended in tank, new tank), fuel lines to handle it. Cutout in bell housing for the flywheel sensor, Mag is serpentine belt not V. Mag heads have an extra boss for acc to mount and much more.. it has been done many times its just not near plug and play.

Yeah, I forgot about the electric fuel pump and potential tank swap. Running a Magnum with a carb gets rid of all the complicated stuff, you just need to re-drill your intake (or is it the heads?) or get one of the few models available for magnum. If you want EFI then one of the self learning kits is the way to go unless you are doing a max effort build, in which case you better polish your programming/tuning skills. But any EFI is going to require an electric pump system and the in tank units are going to be the most reliable. You may need to change your fuel lines too to have a return to the tank of the correct dimension.

 

[rbbruno3]

I’d rebuild the 340 like Scoots said

 

[aussiemark]

Do a compression test on the 340 if the compression is within spec you could try a thicker viscosity oil or even remove the engine and check the crankshaft and rod bearing clearances and fit a new oil pump while you have the oil pan off. I once repaired a 318 that had worn bearings but good crank journals by fitting a set of + .001" bearings (I think you can only do it if the journals are standard size) I am sure the 340 could be repaired a lot easier then fitting the 360 as long as it doesn't have excessive blow by and the compression is within spec.

 

[David B]

I thank y'all for your replies, they were very informative. I am already using 20-50 oil so changing to a different oil probably will not change anything but I'll have a compression check done. What would be the best higher pressure replacement oil pump?

 

[aussiemark]

If you are using 20w50 you can't go thicker I thought you may have been using a lighter oil. The loss of oil pressure is usually from worn bearings and oil pump gears. If you remove the engine and put it on a stand (or upside down on an old tyre) you can check the bearing sizes and crank surfaces and slide new bearings in without having to remove the heads. If the cylinder compression is down or the crank journals are scratched up it would be a waist of time but if they are good it would be worthwhile and extend the engine life at a reasonable price. Fit a new std volume and pressure oil pump, neoprene rear main seal (can be done with crank in the block) new main and rod bearings (same size as what's in there or +.001" if std) and new oil pan gaskets. Check your new bearing clearances with plastigauge just to confirm it's all good.

 

[DetMatt1]

If you are using 20w50 you can't go thicker I thought you may have been using a lighter oil. The loss of oil pressure is usually from worn bearings and oil pump gears. If you remove the engine and put it on a stand (or upside down on an old tyre) you can check the bearing sizes and crank surfaces and slide new bearings in without having to remove the heads. If the cylinder compression is down or the crank journals are scratched up it would be a waist of time but if they are good it would be worthwhile and extend the engine life at a reasonable price. Fit a new std volume and pressure oil pump, neoprene rear main seal (can be done with crank in the block) new main and rod bearings (same size as what's in there or +.001" if std) and new oil pan gaskets. Check your new bearing clearances with plastigauge just to confirm it's all good.

Why not a high volume pump? Since I only run my classics in one climate I run straight 30 weight in my fresh engine and straight 40 in my 156K mile 440.

 

[aussiemark]

High volume pumps keep too much oil in circulation so there is less in the oil pan so if you have a standard oil pan the braking and cornering can force the small amount of oil away from the pick up and allow air to be drawn into the oil pump, they also take more power to turn and put more stress on the oil pump drive shaft and if the tip snaps off it's game over. You can add shims to the relief valve spring to get extra pressure but you don't really need more volume, all that extra oil rains down on the crank on the way back to the oil pan making extra drag and wasting energy. If you set up the bearing clearances and connecting rod side clearances correctly you can get good hot idle oil pressure with the standard oil pump as long as it is in good condition.

 

[David B]

Did a compression check 6-cilinders @150, 1-cyl @140, and 1-cyl @120. So it looks like I need an rebuild. Any recommendations around Jacksonville FL. Checking into a 408 stroker replacement. pros &cons? Are the engine mounts, exhaust, and accessory (alternator, a/c, balancer, water pump) the same so that I can use the ones off the old engine? Can I use the same small block bell housing?

 

[gzig5]

Can't help you in your locality. Blueprint has been getting a lot of good reviews lately for their 408's. They have a couple versions and I think may be working on a short block. I think they are using Magnum blocks now because the LA's are drying up. Pretty good power results and they come with a warranty and support.
https://blueprintengines.com/collections/chrysler-crate-engines

 

[Chryco Psycho]

You need to be careful with the Dakota block if that is what you are thinking of using for the stroker , the Dakota Block is unique with different locations for the engine mounts .
It depends what block the stroker is based on , the LA based block will all take the old alt water pump & AC with no issues, The balancer Will be a problem though , often the stroker will be internally balanced which makes far more sense anyway & you would need a neutral balancer instead of the external balance 360 one as well as needing a different flywheel , where it gets more tricky is in the later LA blocks & the Magnums where the sepentine belt system was used , the serp system will bolt to both Magnum & LA blocks but everything is different , I personally like the serp system over the V belts but the water pump rotates backwards & the alt is different & uses a different pulley , the A/C Compressor will be different also .

 

[David B]

Thank you for the information. My AC is OE so I do not wish to change out the compressor.

 

[moparleo]

On a 340, better pull the heads and see if it has already been bored. May not take another bore job. Thin cylinder walls possible, core shift.