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850 Dp vs 1050 AN

mala

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Anyone know how big the Venturi is on a Proform 1050AN (4150)?
Is it flow more than a Holley 850DP (4781) with 1.75 x 1.56 venturi.?

Thanks
 
1.59 on the 1050AN. I build one a few years ago and ran it on my 511 for a bit. Great carb
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Doubt you'll find anyone that has flow tested a carb, but it sure does stand to reason that there will be some, if not 200 cfm more
 
68 Hemi GTS!
Thats good news. I had a Proform 850DP on for a couple of season before I try my old Holley 850DP (4781) which outperformed the Proform 850DP on the track.
I just put on a 1050AN main body on the 850 proform carb, I hope it be a good street and strip carb. I have only take a spin around town for now.

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68 Hemi GTS!
Thats good news. I had a Proform 850DP on for a couple of season before I try my old Holley 850DP (4781) which outperformed the Proform 850DP on the track.
I just put on a 1050AN main body on the 850 proform carb, I hope it be a good street and strip carb. I have only take a spin around town for now.

View attachment 1290917

I can post my calibration if your interested. Car ram 10.90’s in street trim with that carb.
 
You could measure it to be sure, but I’m pretty sure a PF “850” Race carb(no choke) has a 1.450” Venturi........ so the Holley’s 1.562” in the 4781 is noticeably bigger.
I believe the 1050 annular has a 1.590” Venturi........ but the boosters are more restrictive.
 
You could measure it to be sure, but I’m pretty sure a PF “850” Race carb(no choke) has a 1.450” Venturi........ so the Holley’s 1.562” in the 4781 is noticeably bigger.
I believe the 1050 annular has a 1.590” Venturi........ but the boosters are more restrictive.

If I remember correct PF 850DP is 1.40 and the 950PF is 1.45.... But I can remember wrong.
 
Thanks! I would appreciate that. It should save me some time and gas :thumbsup:


Well I have a book full of calibrations from all the carbs I built on the last 5 years. I thought for sure I documented that one but doesn’t appear so. I’ll have to dig it out and see how I ended up on it. I know I put transfer slot restrictions in the main body to lean out the cruise. But I gotta check to be certain where I sized them at
 
Thanks! I would appreciate that. It should save me some time and gas :thumbsup:

I did tune this with an 02 meter as well so it’s not a seat of the pants tube up. I ran it on a ported TM6. I’d probably run a higher number PV, I’m thinking I was scrounging for a high flow and that’s what I had at the time.

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I have 4 emulsion I my block.

Emu 1 Plug
Emu 2 .028
Emu 3 Plug
Emu 4 .028

IFR .034 Low
TSR .081 I will try a smaller one, still on the fat side.

Thanks for you take time and sharing details.

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Yep, the .078 put me in the high 13’s. I usually start the emulsion in the top hole. I’d move everything up. .028, plug, .028, plug.
 
Had som time to look a little deeper and CLOSER in this carb now.... And what I think was my .028 jets in the EMU was a plugg and NO jets in the other holes :rolleyes: I guess Im getting old and don't pay attention anymore :poke:

This is now corrected .028 plug .028 plug. I enlarged the pvcr from .055 to .063 and it was in right direction..... but not enough. Gona drill a new set to .071 and test.

Now the question! Do I need High Flow P/v now to meet the enlarged pvcr?

Thanks!
 
Had som time to look a little deeper and CLOSER in this carb now.... And what I think was my .028 jets in the EMU was a plugg and NO jets in the other holes :rolleyes: I guess Im getting old and don't pay attention anymore :poke:

This is now corrected .028 plug .028 plug. I enlarged the pvcr from .055 to .063 and it was in right direction..... but not enough. Gona drill a new set to .071 and test.

Now the question! Do I need High Flow P/v now to meet the enlarged pvcr?

Thanks!

Yes
 
Some progress have been made......

I had opportunity to have a test n tune day at my home track, so packing the car with tires, jack, jackstand and... Yeah! You know it. One hour drive on highway.

And I was able to do 5 rounds. I had two rounds with 6.94 which is the fastest time slip I have so far. :)

I have done a little more changes on carb:

Iab 70
Hsab 33
Ifr 36
Tsr 77
Pvcr 71
P/v 8,5
On light throttle 2200-2400 is 13.8 - 14.6 and A/F gauge is erratic / bounce on steady throttle and its feels like the engine buck and surge here.
Q: Do I drive on Tsr or Ifr here?

Thanks

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Ok, so they play together. :thumbsup:

I have to see if I can drill a new set of jets.

Thanks
 
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