hi, i'm looking for a little insight. i got a 83 f-250 with a 300, offy c, edelbrock 600, efi manifolds, hi flo cat and 2.5'' exhaust. it also has a np435 and 4.11s. it seems to work well on the flat and in all gears but 4th. on even a small highway incline it seems almost gutless in 4th gear. I find this odd with the 4.11s. Any input would be great! Thanks

 

What speeds are you driving at when you have this issue, and what size tires do you have?

 

4.11s should bedoing around 70 at 3000 so sounds like either timing, too much fuel or not enough

 

tires, 235/85/r16. i did alot of messing with the timing, 2nd new distrubtor, 1st sheared off a gear. and speed varies if i am at 65 on a small hill it'll stay there or only drop like 5mph, less it will drop more, almost seems like a dead spot floor it and no change in rpm or speed

 

235 85R16s are the same as 32" tires. That'd put you at 2850 RPMs at 65mph. I agree, you should have plenty of power at that point. (I was curious about tires in case you were getting out of your RPM range with the 4.11s).
What transmission do you have? Is 4th a 1:1 or an overdrive?

How old is the cat? Is it plugged? (I know you said it was high flow so I imagine new-er).

Are you certain the vacuum advance is working?

Is the carburetor tuned correctly?

Plugged fuel filter?

 

np 435 sp it should be 1:1, vacuum advance works, dist. is only 4 months old, it does move when ya give it gas, cats like 2 years old, but 1st carb i used was dumping fuel, could that have ruined it? tuning wise the plugs are light brown and only smokes after several days of sitting. maybe valve seals, but no smoke when running normal.

 

i was thinking, 4.11s were too much gear for the combo of tranny and tire size i have, keeping me out of my ideal rpm range, 3rd gear 35mph i'm at like 3000rpm

 

I'm having the same problem. I have the offy dp with an edelbrock 600. I'm running 31s with the 4 speed and 4.11s and granny through 3rd its beast but when i hit 4th there's low power i can hear the 4 barrel kicked in but not much pull. It's running 2000rpm at 55.

 

yea i hear mine opening to, since ya can't adjust a edelbrock to open how ya want it to. is it opening far enough at 2000 rpm, i noticed in 3rd gear and 3000rpm ya really hear it but at 2000 rpm not so much

 

oh its opening all the way its manual secondaries so when i push it to the floor its all the way open also. when i kick it in third at 1500 it pulls hard

 

Did you recurve your distributor or just throw in a reman'd one?

 

yea me too, great in 3rd not so great in 4th. just wish someone could make sense of this for me

 

reman, no recurve

 

You did a lot of mods to the engine. You need to recurve the distributor to take advantage of the mods.


Here's a good link. It's for a big block but same basic info.
http://www.reincarnation-automotive....ons_index.html

 

i do have a mr. gasket re curve kit, 2 springs.