high altitude (9,000ft) QJ on a '86 Dodge 360

[v737d]

Howdy All,

  Apologize up front if this should be in a different forum.

1986 Dodge 360, 4x4 auto. QJ 17085408.
8.5:1 compression, 252 duration on intake and exhaust with 33deg of overlap, do not know lift.
This engine is stock and is used as a snow plow and for runs into Denver in the summer.

The QJ has had a stock rebuild following advice in Cliff's book. Bushed throttle shafts, both sets of plates open exactly 90 deg now, power piston and accel pump all polished. This carb did not come with this truck it was bought as a spare from a "good running" Dodge down in Denver

72 jets
primary rods 54v (that was stamped on them)
.033 (maybe .034) idle tubes
secondary air door spring is 1/2 turn past touching
I didn't note the other parameters like idle down channel or the upper and lower bleeds
if those become important I can get them as the carb isn't on the truck yet.

Looking in Cliff's book in chapter six, he has some very mild changes listed for a Chevy 350 with an "RV" cam 9:1 comp and a cam 204/214 @.050.

so my question is (finally!) is, with this thin air up here is it necessary to change anything and what do you all think of the primary jet/rod combo?

Any and all feedback is appreciated

Cheers

Chris

[Cliff Ruggles]

You've really got to go by how well it works.  If it's heavy on fuel consumption, lacking power, black-sooty pipes, and you can't get a lean "tip-in" with the APT system, I'd drop back one jet number and test it again.

Typically, we take out one jet size for every 5000' elevation.  Lots of other things effect this deal however, including float height, fuel inlet seat diameter, fuel pressure, etc.

Did you install one of our kits for the rebuild?....Cliff

[v737d]

Howdy,

  Yes, I used your kit including the new air door cam plus two new brass idle tubes as I drove them too far down during extraction!

  Float height was set to 15/32, it was easier to get a reading at that height than 13/32, probably a rookie move!

I didn't measure the fuel inlet but it does have an external electrical pump so in theory We should be able to dial in the fuel px.

Stock fuel px is 5.75-7.25 psi using a stock mechanical pump

I admit I was being lazy and hoping for an easy quick solution! I will install and get back here with results.  I can then get whatever jets are in the current QJ


Thanks


Chris

[Cliff Ruggles]

Float level is too low, I'd raise it up since you have a regulator to control the pressure.  This will leave more fuel in the bowl to offset evaporation between uses.....Cliff

[v737d]

Will do!  So far it seems to running fine at idle, and part throttle, haven't tried anything more rigorous yet.

Really appreciate all the help

Cheers

Chris