388 gov spring?

[dpuckett]

It's not a typo- I have a 388 spring that came in the pump in my W350. It had been rebuilt once before I got it, and when I swapped tops a while back, I just put the spring and the whole shebang from the old pump on the "new" pump. I noticed that the number on the spring looked an awful lot like a "388" but thought it WAS kinda faded, and could well have been a 386. But, today, I resealed the top for the "new" pump, and put it back on, and compared the springs, and the 388 is about 2-3 coils shorter. Anyone have any clue what application it is from?

With the fuel screws within 1/2turn of one another between the 2 tops, I can go 31mph in 2nd w/ the 388; about 25mph w/ the 386- a 20% difference in RPM. The 388 seems to split the difference between the 366 (3200) and the 386 (stock).

I put the (stock) 386 spring in, and for the purposes of trying to eek every mile from a gallon of fuel, I am going back to 100% bone stock settings for a reference/ starting point . My green truck never got 20+ mpg after I installed the 366 spring, and I have a feeling the springs may affect the MPGs in some cases. And it may not....

Dan

[Oddfire]

I have a VE off of a skidder next to my tool box at work that has the same spring in it.

[bgilbert]

It's just a stock Dodge or actually Bosch spring. 386 and 388 are both found in our trucks. I would guess cpl or model year might determine which spring the pump got.

[gear jammer 91"]

My non-intercooled pump had the 388 spring in it. I can't remember if my brothers intercooled truck had the 388 or not.

[dpuckett]

The differences in the springs would explain how some guys can reach 3000 pretty easy, and others struggle past 2500.

[GO OVRIT]

My intercooled trucks have all had 386's but RSWORDS non-intercooled truck had a 388.

[Begle1]

So what's better, the 386 or 388?

Maybe I had the better of the two and that's why I hardly noticed anything with my 3200 RPM spring.

[gear jammer 91"]

Now I'm all confused, I just found what I think is the stock governor spring from my truck and it say' 386 . I've done two gov springs, one in my non-intercooled truck, and one in my bro's intercooled truck. I don't know for sure which truck the spring I found came out of. When I put the 366 spring in my truck , I noticed a hug difference, my brother didn't seem to notice as much of a difference as I did.

[dpuckett]

I'd venture to say the 388 is a higher RPM spring than the 386- it is shorter. With the 386, I have slightly less top end in each gear- 45mph is about it in 3rd now, vs 50 coming easy with pedal left over with the 388.

Daniel

[90FIRSTGEN CUMMINS]

I did my gov spring not all that long ago and my truck had a 386 spring. My truck is a non intercooled 1990.