gerard

Just wanted to see if anyone had good results with p and p of a carb. I have a q-jet and deburred it and polished it didnt notice a change in power but a slight improvement in gas mileage.

Sonix

iTrader: (1)

what parts did you port polish or deburr? The venturis? huh, figured that would be a bad thing as far as fuel mixing...?

Apeiron

You don't really have to touch the venturis to make improvements, you can radius the entries into the throats, deburr the edges of the boosters, narrow the booster legs, etc.

Nebu

i've done it

nebu.

gerard

Any hp improvments?

Nebu

my buttdyno hasn't noticed much of a difference. maybe a little.

Sonix

iTrader: (1)

oh right, Tony'78Z I think is his name, try searching for a few posts by him. I think he put a 350 in a datsun 240z or something... anyway, in his sig he has a fair bit of info on that on his q-jet, very nice paint pictures as well.

firebirdjones

I run an 850 dp holley on the chevelle and experimented with it. I cut off the choke housing, polished the venturies, boosters, and smoothed the transition into the top of the carb, and it looks much like the carb in the picture above. It was very labor intensive and time consuming, not worth the time and effort it my opinion, because you are still stuck with an old main body that doesn't have adjustable air bleeds, among other things.
In the end, I had the carb apart so many times at the race track for jet changes and what not, that eventually the screw holes started stripping out, The rear squirter was also stripped from removal and reinstall, it basically had met the end of it's life span so I ponied up and purchased a Pro Form main body, (had to go pro form since holley is not making an 850 main body available seperate, Yet anyway) it's a very slick main body that required no grinding/polishing and has adjustable air bleeds as well so it is more tuneable.
Once I had the jetting dialed in the car picked up about a tenth and almost 1 mph from it's previous best.
In my opinion, it's not worth all that effort when you can spend a measly $125 for a nice main body and be done with it,,,and it's better than anyone can do by hand.
With a Q-jet you are pretty much on your own though, as I am not aware of any aftermarket Q-jets that come this way,,which is too bad, I would like to try one on another car of mine if that were the case. Larry.