Billet Meter blocks for 850 DP... your thoughts?

[mbaird]

I have a 850 DP that I am installing Quick Fuel billet/Adjustable metering blocks on . These come with blank bleeds for emulsion / PV and fuel restrictors.

My research indicates Drilling air bleeds to .028 to start with .

Anyone install these before with success ? Where did you start as a baseline ?

 

[yellow rose]

I have a 850 DP that I am installing Quick Fuel billet/Adjustable metering blocks on . These come with blank bleeds for emulsion / PV and fuel restrictors.

My research indicates Drilling air bleeds to .028 to start with .

Anyone install these before with success ? Where did you start as a baseline ?
View attachment 1715590058

.028 emulsion is a good start. Use them in 1 and 3 from the top and block 2 and 4.

Move the idle feed restriction down. You’ll probably have to tap the lower holes.

Depending on carb size and what your doing, the IFR can be from about .026-.034 and the IAB should be in the .068-.072 range to start.

I check the T slots and see how wide and long they are, but I haven’t found any yet that I wouldn’t use a T slot restricter on. I start at about .078 and tune from there.

 

[mbaird]

Thx...
this is going on a fairly mild 5.9 with a 221/229 @ .050 cam and Brians IMM ported EQs.
It is a bit of overkill but this is more of a learning experiment .
I am having trouble cleaning up the 1800-2400 rpm range with the current 750 VS aand I bought these blocks cheap so I thought it would be fun to try them out on the 850.

 

[yellow rose]

Thx...
this is going on a fairly mild 5.9 with a 221/229 @ .050 cam and Brians IMM ported EQs.
It is a bit of overkill but this is more of a learning experiment .
I am having trouble cleaning up the 1800-2400 rpm range with the current 750 VS aand I bought these blocks cheap so I thought it would be fun to try them out on the 850.

That makes sense. The RPM range you are having issues with is because you are at the end of the transfer slot, and the main is delayed by a small MAB. I have fought this before, especially on TR stuff and/or stuff with lower gear ratios.

It finally dawned on me that Holley and all the clones are using a MAB that is too small to DELAY the booster because the rest of the tune up is so wacky.

FWIW, a smaller air bleed DELAYS the mains starting, and makes the fuel curve richer at RPM.

A larger air bleed STARTS the mains sooner, and makes the fuel curve leaner at RPM.

Holley carbs are notorious for being pig rich on the bottom, lean in the middle and pig rich on top. Been that way since I started driving in 1980.

Why Holley sends out a tune up in their carbs like that, I can’t say. But that is the defacto tune up they and most every clone I’ve seen is done.

 

[mderoy340]

This setup works for me at sea level, 750 proform street strip, tight converter, [email protected] cam, 4.10 rear gear.
I have found it better to extend the idle circuit and delay main feed on my car.
IFR .035 bottom feed, .067 IAB, idle mixture 4 corner 3/4 turn area, TS restrictor .081. If I go any leaner than .081 the 60' gets hurt.
PMJ as lean as you can get without surge. I run 72s .077 diameter, PVCR .063, PV 9.5 4 hole feed, MAB .026
Cold air sealed intake air is a must and adjust idle mixture ONLY when engine is at operating temp.
A motor with no choke that cold starts and runs with no need to feather the throttle for a little bit is going to be pig rich at operating temp.
IMO an 850 at your elevation is going to be a bit much.

 

[mbaird]

The 850 just happens to be what I have left on the shelf. Again....this is more of a learning excersize. A properly tuned 750 VS would be optimal for this engine. I guess I could use one of these plates to modify my current 3310-2

 

[Dana]

Nice: straightforward, well informed question, no BS well informed responses. Very nice.

 

[yellow rose]

This setup works for me at sea level, 750 proform street strip, tight converter, [email protected] cam, 4.10 rear gear.
I have found it better to extend the idle circuit and delay main feed on my car.
IFR .035 bottom feed, .067 IAB, idle mixture 4 corner 3/4 turn area, TS restrictor .081. If I go any leaner than .081 the 60' gets hurt.
PMJ as lean as you can get without surge. I run 72s .077 diameter, PVCR .063, PV 9.5 4 hole feed, MAB .026
Cold air sealed intake air is a must and adjust idle mixture ONLY when engine is at operating temp.
A motor with no choke that cold starts and runs with no need to feather the throttle for a little bit is going to be pig rich at operating temp.
IMO an 850 at your elevation is going to be a bit much.

I can certainly see that TSR being about as small as you can go with your combo.

BTW, I use 10-32 for the T slot restricters. I know some guys use 8-32 but I’d put need bigger than about .078ish (IIRC) the drill gets into the hex of the brass.

 

[mderoy340]

I can certainly see that TSR being about as small as you can go with your combo.

BTW, I use 10-32 for the T slot restricters. I know some guys use 8-32 but I’d put need bigger than about .078ish (IIRC) the drill gets into the hex of the brass.

Agree. I'm using 8/32 and the .081 is max for me when center drilled. I would need to go with the 10/32 to go bigger. I'll add that the TS diameter change is very sensitive, .076, .078, and .081 are big steps.