Mild power upgrade 318la?

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billy

Motor mouth ratchet jaw!
Joined
Nov 15, 2009
Messages
3,935
Location
helifino USA
If i was ever in the right place for a question like this.
Here it is!
I have a 2bbl no name carb on my almost 8000lbs ambulance.
I think it is 500cfm
And going up grades it just doesn't seem to have enough oomph to even keep it at 45mph
(Which with the gearing is approaching max speed)
Since i have no money or skill for cams,headers blabla
Would a pertronix and a slightly larger 2bbl get me the small amount of power i need?
 
Sounds like it might just be tired Billy. I'd do a compression check to see how it compares to stock specs, the rings and valves may have a lot of leakage if it's a high mile engine. The better ignition might help a small bit, but unless your current system is breaking down under load you may never tell the difference.
 
a lot of them sized vehicles have governors built in the carb, see if you can re-machine or add an adapter to fit some thing like a Holley 3310 vacuum secondary carb.

OR change gear ratios to lower the RPM on the road.
 
8,000 pounds may be taxing the 318 however, it should pull it pretty good.
Timing would be a big issue. Check it to make sure it's where it should be. If you have to, advance it more and run premium fuel.
If I remember right, you installed a new carb and to me it didn't look like it had a governor on it.
 
I just pulled a perfectly good 5.9 Magnum (360) out of my '47 Dodge pickup that will slide right in the place of your 318. Just sayin.....
 

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Since you mentioned Pertronix, I assume you have points... if their condition and dwell are off, they can give the "loaded diaper" effect.

Timing would be a big issue.

The best way to remove power is... suck the timing out of it. :mad: Make sure your advance devices work properly, vacuum diaphragm and line, mechanical weights moving FREELY and completely.

.
 
I worked on a job that had a (fairly new then) 72 Dodge 3/4 ton crew cab. It had a stock 318 that could get 3rd gear scratch with 250 gallons of fuel in the back and bury the speedometer with no problem at all. That said, I think you have plenty of engine, just needs to be in good tune. Which begins with a proper compression test to see if it is tunable. Doubt it has 500 cfm and also doubt more carb waould make any difference except using more gas.
 
Wish I knew someone around here that knows anything about carbs.
You do of course willowbilly but
1 you are a ways away
2 you a busy guy
 
I'd move on the the Petronix module then drive it to see if that was the issue.
If you do a bunch of different things all at once, you won't know which one it was that fixed it.
 
Billy, I'll throw my story into the ring.
Years ago I had a 318LA [with two barrel carb] in a single axle grain truck. We routinely hauled three hundred bushels of grain in it and it seemed to be able to handle the heavy vehicle. The motor was just adequate at highway speeds, loaded, but it worked for us.
Good luck getting a little more oomph out of yours.
 
The timing was way off.
We couldnt even see the mark with the light until i rotated the distributor about 3 inches. I disconnected and plugged the vacuum advance
Then
We set it at the 10 mark and it starts instantly and seems stronger.
Going to try the long uphill highway tomorrow
 
Last edited:
Since you mentioned Pertronix, I assume you have points... if their condition and dwell are off, they can give the "loaded diaper" effect.



The best way to remove power is... suck the timing out of it. :mad: Make sure your advance devices work properly, vacuum diaphragm and line, mechanical weights moving FREELY and completely.

.

Where are those and what do they look like?
 
under the distributor rotor couple of fly weights make sure they move freely make sure vacuum advance works
 
if it is a 318LA,

a set of 340 heads and a decent cam, along with a 180 degree hi-rise manifold and 600cfm vacuum secondary Holley will add a bunch of HP to it.

the original 318LA motors had a limp-dick 360 deg. open plenum manifold, that breathed like an asthmatic sled dog.
 

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