|01-12-2014 08:20 PM|
No dyno or track test but here's my experience with my B150 with a 318. Bone stock 318 2 bbl ran ok and was getting just under 11 mpg on the hwy. Previous owner had stated a local Vo-Tech had rebuilt the engine at 105,000 because they forgot to tighten the oil drain plug after an oil change and the plug came out. The engine always started with a puff of smoke but was clear that it was only the short block that got rebuilt.
I pulled the heads and did a valve job. While it was down I installed a white box RV cam, 204@ .050 int, 214 @.050 ex. Don't remember the lift but it was .420-.430 ish. The valve guides needed shortened slightly for retainer clearence. Added a performer intake and a 600 vac sec holley out of my collection of old carbs. The van was much peppier and best jetting yielded 12 mpg. A switch to an out of the box Edelbrock 600 also got 12 mpg. Best jetting efforts gave 13.5 mpg. This was 3 steps lean on the cruise an 2 steps lean on the power. The step up springs had to be changed to allow for smooth part throttle accelleration. Seat of the pant performance felt the same as with the holley.
This combo was a daily driver over 10 years until I sold it. Below 0 weather or over 100 degrees. Slight problems with vapor lock in warmer weather was solved by adding a thermostatic controlled electric fan and electric fuel pump.
|01-12-2014 12:29 PM|
I'm looking forward to your reports. I have a 1984 W150 with a 318 that I will start a rebuild on in a couple of months and I'm interested in the Cam information comparison to help me make a selection.
|12-23-2013 03:44 AM|
|631604hemi||im doing a 318 on my 90 w 250...took the 360 out...302 casting heads and a 4 barrel...trying different cams on a dyno....looking for mileage and torque...|
|01-10-2013 02:30 PM|
TBI systems can provide a benefit. However if your altering the base engine with larger valves and such, a carb is so dynamic and freindly. I would chose a edelbrock AVS or afb around 600-650 cfm. The AFB/AVS is easy to tune, rebuild, and very staight forward. The intake for pulling would stick with the performer 318 to keep continuity of the small head runners. It will stimulate the low end for pulling and towing.
If you want more on the Magnum swap look into Moparts.com, and make this post. You can get a pair of magnums around $179.
|01-10-2013 10:29 AM|
Thanks for all the great informations!
As much as i would like to upgrade the entire head i most likely will stick with my 318 heads.
Since i need new valves anyway i think i can go bigger.
So what about the TBI or carb option?
Does anyboy know if the TBI is capable to deliver the fuel for my mini upgrade?
How about tuning that all in?
just keep all the information coming!
|01-09-2013 03:01 PM|
|spinn||Which mopar performance porting template did you use as a port guide? Not one set of templates will flow those numbers on a 2 bbl 318 675 head.|
|01-09-2013 02:01 PM|
common 318/two-barrel valve sizes of 1.78/1.50-inch and in stock trim flow about 135 cfm stock on the intake side
The fully ported heads with larger valves installed showed an intake flow improvement of nearly 60 percent to a respectable 215 cfm at a peak of 0.500 lift.
Its a stretch but the heads "can" be modified.
not sure its worth it if you pay someone for the porting...
|01-09-2013 01:26 PM|
Whats needed for a magnum swap.
Magnum Head Assembly MP# P5007086 (two required)
Magnum rockers, stands, guide plate, and bolts: MP# P4876050 (eight required)
Special length Pushrods: MP# P5007477
Mopar/AMC lifters: Comp Cams #822 or MP4529220
Magnum head bolts: MP# P4876759
Magnum valve covers (desirable, maybe not required)
MP Magnum intake OR
Modified LA intake OR
Bushed and re-drilled heads (to adapt LA intake)
Spark plugs for Magnum heads - I used Autolite #3923
Standard LA gaskets
Throttle cable bracket from MP (only used with vertical drilled intakes)MP# P4876850
Throttle return spring bracket from MP (only used with vertical drilled intakes): MP# P4876313
Some mopar heads info
The 675 is a small 318 head Not closed chamber.. The 587 heads are the 340/360 heads used in 1973/74 up through in some cases 1976. Most OEM 915/587/596/974 CC'd in the area of 72 CC's. None of the above heads are closed chamber heads.
-302's are closed chambered sbc heads. 051's ase closed chamber. Both are poor performers. Might flow 170cfm intake.
323LA RPM type intake and 340hp cam, mopar 360 magnum head swap made 237rwhp at 6100rpm, and 4000rpm 319lb/ft of max torque. Before magnum head swap had 278lb/ft of torque at the same 4000rpm, and 211hp at max 5800rpm with 318 port 051 Heart shaped LA heads.
|01-09-2013 01:12 PM|
No , they dont.
318 heads are terrible.
|01-09-2013 01:10 PM|
|vinniekq2||Some 318 heads work very well with 2.02 valves and mild porting. 380 hp in the carbed version is common.No idea what part numbers for dodge applications.Let us know which direction you follow? I would love to see a mild 350 HP 318 in a dodge truck.|
|01-09-2013 01:00 PM|
A magnum head swap is very effective. You get better chambers, the 1.92 valves, and they bolt on. Mopar makes the pushrods needed for the conversion.
The 340 hp mopar performance cam .430/.443 lift, is great for a driven vehicle.
|01-09-2013 12:50 PM|
Chrysler 318 rebuild in Dodge RAM W150
Im going to rebuild my 88's engine and transmission.
Im not looking for too much of an performance upgrade but like to get ur opinion.
Im looking to build a stock motor with a rebuild kit from summit (Part# MHP152-322). Comes with sealed power cast aluminum pistons (Part#Z285AP30) that would bring compression to around 9:1.
I like to open up the valves to 2.02 intake and 1.60 exhaust and run Comp cam part#20-220-3 with grind XE250H.
I believe that would work nice in a 4500 pound truck that I like to use as a daily driver and to pull trailers.
As you can see this will be a budget built and Im aware that the performance will be limited.
Now, do you think that will work or is there better combos for similar cash?
Will it make sense to use bigger valves or is that not helping much?
Also since this is a 88 engine it comes with the TBI fuel system.
Im debating if I should convert to a carb or if it would not be worth the effort. Did anybody do that already? What is all involved?
And if I go carb what manifold would be good?
Any help will be greatly appreciated!