mcmopar
Well-Known Member
Since I've been off work the last couple of weeks I decided to do a few things around the house and also work on the car. I've had a Holley 850 Double Pumper carb sitting on the shelf in the garage for awhile now and decided now is the time to rebuild it and install it. I got the rebuild kit about 10 days ago and started the rebuild on Wednesday. Everything went a-ok but when I put in on the car I had some "technical difficulties". A quick call to my buddy Jim verified my suspicions so I made the necessary float adjustments and tried again today. I got it idling ok but it stumbled as soon as I touched the gas pedal. I called a local speed shop to see if they had some pump squiters and found a pair of 40's to try (the carb had 32's on it). A quick swap and the stumble still remained. The guys at the speed shop said that if the squiters didn't solve the problem I'd need a new pump cam. Well, the one on the 750 I had on the car worked great so I swapped out the pump cams and 
it worked just like down town! No more stumble. Then I swapped out the 35 squiter on the primary side of the 750 to see how it would do and it also works fine. I may go back to the 40 or get a pair of 37's as the 35 seems just a touch too small. With the 40 squiter on there it feels great off-idle but it may be just a tad too big.
At any rate, the car now idles a bit more aggressively than it did with the 4 corner idle 750 (the 850 DP only has 2 idle mixture screws) but it now pulls 3-4 more inches of vacuum at idle. Another benefit of the 850 DP is that it smells far less "dirty" at idle. The 750 seemed to run just a bit too rich at idle causing it to really be tough to be near. It really was bad. Now, it seems a whole lot less rich and "dirty" smelling. Now maybe the crowd at Old Town won't need their gas masks as I cruise on by!
I've yet to road test it but if the weather holds (40% chance of rain later) I'll run the 24 miles on down to Old Town tonight and shake it down. :cool: All I have to do is be a good boy and keep my foot out of it. Don't want any trouble with the local constabulary! :drive:
it worked just like down town! No more stumble. Then I swapped out the 35 squiter on the primary side of the 750 to see how it would do and it also works fine. I may go back to the 40 or get a pair of 37's as the 35 seems just a touch too small. With the 40 squiter on there it feels great off-idle but it may be just a tad too big.At any rate, the car now idles a bit more aggressively than it did with the 4 corner idle 750 (the 850 DP only has 2 idle mixture screws) but it now pulls 3-4 more inches of vacuum at idle. Another benefit of the 850 DP is that it smells far less "dirty" at idle. The 750 seemed to run just a bit too rich at idle causing it to really be tough to be near. It really was bad. Now, it seems a whole lot less rich and "dirty" smelling. Now maybe the crowd at Old Town won't need their gas masks as I cruise on by!
I've yet to road test it but if the weather holds (40% chance of rain later) I'll run the 24 miles on down to Old Town tonight and shake it down. :cool: All I have to do is be a good boy and keep my foot out of it. Don't want any trouble with the local constabulary! :drive:
