new to me engine - what to do with it ?

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mikemann00

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Hey to everyone , New here and I know its not an a body buts its a smallblock and I didn't know where else to go , I just picked up an 85' D150 shortbed with the following build , My ? is It runs great and sounds mean but doesn't seem to have the power I would assume it should have , Anyone see anything wrong here or need to change anything , It is a 85 318 block full rebuild with stock replacement pistons (so low in the hole) , rebuilt 340 x heads , summit k6900 cam , edelbrock performer intake and 600 carb , summit headers , 2 1/2 duals to flo-master 40's dumped before the axle , Mopar orange box ignition , rebuilt 904 trans with b/m shift kit , 3.73 rear ,Don't get me wrong she goes just seems a bit off , Wonder what the hp might be as is and im assuming im down on compression so how to fix that without much trouble or just leave it be ? No racing just a daily cruiser is all its for , Thanks in advance
 
You asked,For a daily driver,I would let it be. Check you tune up and play with timing and possible jetting(Edelbrock carb?) to squeeze a bit more.Was the cam installed straight up?Cam specs?The truck is a bit heavy compaired to a car. My 88 D350 Non dually tips the scales at 5000 pounds give or take. It too has a bone stone stock 84 318 with a thermoquad and 4.10 gears.Great for a driver but no powerhouse.
 
What is the tune up on it? TIming curve specifically. What distributor are you running?
 
I did buy it just to drive it really because the price was way too good to pass up and who cant use a truck ,
Darter6 - don't know what you mean by cam straight up ? , edelbrock 600 carb
barbee6043 - it weighs in at 3760 with me in it and half tank of fuel - scaled at a pilot truckstop on the way home
Moper - stock vac dist. with stock replacement items for now - going to tweak the carb with a vac gauge and do an ignition upgrade and then probably just drive it - Hate to pull it apart as it only has 3500 miles on it

Cam specs = Basic Operating RPM Range:1,200-5,000
Intake Duration at 050 inch Lift:204
Exhaust Duration at 050 inch Lift:214
Duration at 050 inch Lift:204 int./214 exh.
Advertised Intake Duration:278
Advertised Exhaust Duration:288
Advertised Duration:278 int./288 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.421 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.444 in.
Valve Lift with Factory Rocker Arm Ratio:0.421 int./0.444 exh.
Lobe Separation (degrees):112
 
Do a search for degreeing a cam and the reason for it.A few degrees advanced or retarded will make a difference for each application.Straight up is when you align the cam sprocket mark (usually a dot on the gear) with the crank sprocket mark.
 
If those are 340 X heads on there that's not helping you @ all! Those big 2.02 valves are really hurting you down low where you need it most! Sell the Xheads & with the good money you get from them put that money into a nice set of 302 casting swirl port 318 heads. It will also give you a bump in compression aswell becouse of the smaller chamber. That will wake it up for sure!
 
The x heads may be lowering the compression more than it was stock, but they will flow better and perform better than the stock heads.


A set of Rhoades lifters part # 2018 may help get the cylinder pressures up. Read the second article on this page for more info....

http://www.rhoadslifters.com/Pages/Articles.html


Or put some higher compression pistons in it. If you put 10.5 compression pistons for a 318 in there, you will end up at 9.2 with the x heads. I've built a 318 like that before and it worked great. .

Here's a link for a Mancini Racing "refresh kit C" that comes with gaskets, bearings, rings, pistons, freeze plugs, and oil pumps for $400. It may be worth it to get the gaskets and pistons alone, much less the oil pump, freeze plugs, and bearings.

http://www.manciniracing.com/sealpowkitc.html


Here's a link to the main page with other "refresh kits" for more options.

http://www.manciniracing.com/enrebkit.html
 
do you have a tach in it? does it rev at least to the 5k your cam card calls for smoothly?

if not i'd think about swapping for a known, good ignition box...the mopar units have never impressed me. I had 2 Mopar boxes only letting my first engine (also a 318) rev to 4000. Threw in a MSD box and it would rev to 6K. Not saying you need to go as far as an MSD box...but at least worth swapping for a known working unit. @ 3700 lbs you surely aren't the heaviest thing on the road, but it is some weight to lug around. The heads are probably a bit much for a mild cam 318, but mopar heads don't exactly flow to the moon in stock form so i don't think they are killing you.

I'd maybe borrow and test another carb, box, and check your timing. If neither of these really wake it up, maybe it's all it has.

I'd buy a test n tune ticket when the tracks open up for $20 and take it down the quarter mile.
@ 3700 lbs, and hoping that engine makes what? 250 HP? you should be well into the 15's

if you run a 18.00....you're making approx 150 crank.

check this link out for giggles

I had an old K10, with a bone stock 305 that ran 18.00 and that engine was 160 rated from the factory, and it was probably 4000 lbs. surely i'd hope you did better than that sled!
 
2.02 +Low comp 318+heavy truck=NO BALLS! down low. Period! Even with higher comp it will need a good 2500-3000 stall to get air flow moven to take advantage of the big valve heads! Ask how i know...
 
Thanks for all the replies guys...
Darter6 - No idea on the cam as po built it , any way to figure that out ?

Hipo65 - trying to decide on a head swap or a piston swap - getting conflicting stories on both.

KrazyKuda - thanks for the links i'll check em out.

Johnymac2k6 - Yes it has a memory tach in it and yes it revs to 5k no problem and pulls pretty good doing so but poor off the line , Plugs , wires , cap , rotor and FBO ignition on the way , then a tune on the carb to see what happens then.

Again daily driver parts getter here not a drag truck at all
 
Nice looking hauler.

The heads are causing the engine to be down on compression and intake charge velocity.

As far as pistons go, suggest using a 67-70 piston. These set highest in the hole.

IMHO the best course of action is to keep what you have and enjoy the truck.
 
2Darts..Thank You! The keith black pistons are pretty nice to. Smaller valve/port heads with small chambers will help bucket loads down low. or go with a reeeeaaaallll loose converter with current combo. Velocity is king with smaller displacement!
 
Get a compression test. Rip the timing cover off. Get the Mopar offset cam key kit. Keep the compression gauge screwed into #1. Advance the cam 4* and recheck compression. If there's not a big difference, advance it 4* more. slap it together and re tune and drive. I bet you add 25 LB FT or more down low. Over and out.
 
I appreciate all the input from everyone , I do believe im going to go with 2 Darts and Darter6's earlier post and just run it as is and enjoy it for now , It doesn't leak , It has no rust , everything works and it turns heads the way it is , Plus it gets 14 mpg with spirited driving , probably do better if I kept my foot out of it a little but that's no fun , Ill keep an eye out for another set of heads and when I feel like tearing it down i'll go for the swap and sell the X's leaving the bottom end alone since its all new anyway , Thanks to all again.
 
mikemann00 said:
here she is
Click to expand...

That's an extremely nice truck you scored. I'm in the process of resto/modding my own '83 D150 318 4 speed.

As you already know your 318 is suffering from low low compression more than anything else. Just drive it or move up to larger cubes-forget upgrading the stock stroke 318. J.Rob
 
Thank Ramm , Ill probably do a head swap in the future but that's it on this one , Just want to keep it a nice dependable daily , Here is my previous 82 , 318 4-speed ,
 

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Dcr. Your Dcr is in the basement.
Sell that teener, get a 360.
Or put those heads on a zero-deck 360 short block. What ever you do throw that cam AWAY. Those lobe ramps are way too slow (278-204=74*), which , with those large open chamber heads,are costing a ton of compression, which is showing up as a soft bottom end. No tune on the planet is going to overcome that problem,on the teener.With a 360 having about 86cc more swept volume, those heads will/might be tolerable.
There is another option. A nice set of closed chamber 318 heads and a new fast-rate cam. That will pull the Dcr up and give that little teener a fighting chance of getting off the line in a reasonable manner.That and maybe a smidge more gear. I too have an D100/teener. Its an 84 reg box.
Sweet truck,yours.
 
Thanks AJ , The heads will be swapped one day in the future but your the first saying to ditch the cam or is that just with the x heads , didn't really want to do heads , cam and possibly pistons on a fresh motor (reason im driving as is for now)
 
Thanks KrazyKuda , I had a 67 Dart in the past and a 70 Cuda but it seems lately ive fell into a few trucks for the right price and they serve dual purpose (Fun and usefull).
 
I ran a similar setup in a mud truck, except with J heads and low compression. Hadl ots of torque but no top end. Put a set of bone stock 318 heads and really woke it up!
 
Im building a d150 also, my trucks stock weight was just under 3600 lbs. Doesnt really seem to bad to me. If its really bothering you, you can pull the heads, measure CCs have them cut down for compression, Get some thin head gaskets. Im not a big fan of the performer intake, Had better luck with the stock cast iron 360 intake manifold, with the divider cut down. Or do magnum head swap, and a new intake?
 
Pauly - 318 heads are what im thinking for the future.

Moturbopar - Its really not that bad as is , waiting on the new ignition to arrive and going to time and tune then and see what happens , po set it at stock specs so that's where that is , I know it needs more timing and my vac gauge just showed up today , next day or so and we will see what happens if the ignition stuff shows up .....
 
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