Holley 870 street advenger - junk?

[Bewy]

You do not mention the cam specs, but using a Super Victor, 11:1 CR & a 5200 rpm c'ter suggests it is sizeable. That is going to require a couple of things: plenty of timing at idle [ 24* is probably ok, but could need as much as 50* ] & increased air for idle, facilitated by bypass air, BPA ].
I only use Holleys for door stops, so not sure if your model has adjustable BPA. If it doesn't & you have a sizeable cam, the usual fix is to drill small holes in the t/blades for extra BPA. You say the t/slots are 'properly adjusted'. How was this done? From your description, it does sound like the t/slots are open too far. Putting 0.014" wire in the IFRs might have reduced available idle fuel such that blades had to be opened further to facilitate idle; hence stinky idle. Screwing the mixture screws fully in should stall the engine. If they don't, it is another sign that blades are open too far & idling off the t/slots.

 

[Retroboy]

You do not mention the cam specs, but using a Super Victor, 11:1 CR & a 5200 rpm c'ter suggests it is sizeable. That is going to require a couple of things: plenty of timing at idle [ 24* is probably ok, but could need as much as 50* ] & increased air for idle, facilitated by bypass air, BPA ].
I only use Holleys for door stops, so not sure if your model has adjustable BPA. If it doesn't & you have a sizeable cam, the usual fix is to drill small holes in the t/blades for extra BPA. You say the t/slots are 'properly adjusted'. How was this done? From your description, it does sound like the t/slots are open too far. Putting 0.014" wire in the IFRs might have reduced available idle fuel such that blades had to be opened further to facilitate idle; hence stinky idle. Screwing the mixture screws fully in should stall the engine. If they don't, it is another sign that blades are open too far & idling off the t/slots.

You do not mention the cam specs, but using a Super Victor, 11:1 CR & a 5200 rpm c'ter suggests it is sizeable. That is going to require a couple of things: plenty of timing at idle [ 24* is probably ok, but could need as much as 50* ] & increased air for idle, facilitated by bypass air, BPA ].
I only use Holleys for door stops, so not sure if your model has adjustable BPA. If it doesn't & you have a sizeable cam, the usual fix is to drill small holes in the t/blades for extra BPA. You say the t/slots are 'properly adjusted'. How was this done? From your description, it does sound like the t/slots are open too far. Putting 0.014" wire in the IFRs might have reduced available idle fuel such that blades had to be opened further to facilitate idle; hence stinky idle. Screwing the mixture screws fully in should stall the engine. If they don't, it is another sign that blades are open too far & idling off the t/slots.

You do not mention the cam specs, but using a Super Victor, 11:1 CR & a 5200 rpm c'ter suggests it is sizeable. That is going to require a couple of things: plenty of timing at idle [ 24* is probably ok, but could need as much as 50* ] & increased air for idle, facilitated by bypass air, BPA ].
I only use Holleys for door stops, so not sure if your model has adjustable BPA. If it doesn't & you have a sizeable cam, the usual fix is to drill small holes in the t/blades for extra BPA. You say the t/slots are 'properly adjusted'. How was this done? From your description, it does sound like the t/slots are open too far. Putting 0.014" wire in the IFRs might have reduced available idle fuel such that blades had to be opened further to facilitate idle; hence stinky idle. Screwing the mixture screws fully in should stall the engine. If they don't, it is another sign that blades are open too far & idling off the t/slots.

The transfer slots are just barely visable from underneath, the engine responds happily to the mixture screws. I haven't drilled the butterflies yet. I have come from mechanical injection on methanol, a 750 methanol carb, and now this petrol nightmare. I regret selling my previous set up's.

 

[Hysteric]

The transfer slots are just barely visable from underneath, the engine responds happily to the mixture screws. I haven't drilled the butterflies yet. I have come from mechanical injection on methanol, a 750 methanol carb, and now this petrol nightmare. I regret selling my previous set up's.

Get an old 650 or 750 DP and be done with it.

That 870 is a street carb.

 

[RustyRatRod]

Get an old 650 or 750 DP and be done with it.

That 870 is a street carb.

With his combo, I tend to agree about the DP, but there are way better, more modern options.

 

[Hysteric]

Get an old 650 or 750 DP and be done with it.

That 870 is a street carb.

Stick it on Gumtree

 

[Retroboy]

I have a foot injury that makes it difficult to operate the secondaries on a DP. I have 30 km's each way to get methanol and my local track closed a couple of years ago with zero notice. My nearest track is 5 hours each way. One of my crew guys has just finished the resto on his 65 Nova super stocker so I only having one regular guy I want to make my life easier so petrol carb. When I started racing in the 1980's I ran a 3310 750 Vac Sec and after it was set up with a secondary metering block, no power valves, wire restrictors etc it had dynamite throttle responce and ran clean as a whistle. I ran 9.70's with that on a very basic small block Ford. The difference was track time
I don't see why this 870 won't work just as well given sorting

 

[Hysteric]

I don't see why this 870 won't work just as well given sorting

I don't either. If you're prepared to keep at you can make it work but it will take time.

 

[RustyRatRod]

I have a foot injury that makes it difficult to operate the secondaries on a DP. I have 30 km's each way to get methanol and my local track closed a couple of years ago with zero notice. My nearest track is 5 hours each way. One of my crew guys has just finished the resto on his 65 Nova super stocker so I only having one regular guy I want to make my life easier so petrol carb. When I started racing in the 1980's I ran a 3310 750 Vac Sec and after it was set up with a secondary metering block, no power valves, wire restrictors etc it had dynamite throttle responce and ran clean as a whistle. I ran 9.70's with that on a very basic small block Ford. The difference was track time
I don't see why this 870 won't work just as well given sorting

I certainly don't know your injuries, but I believe you may be talking about the older DP carburetors that have the semi round slot linkage. They are more difficult to operate, I agree. But the newer ones are just as easy as the vacuum secondary carburetors. Find someone with a newer one and try it before you give up. You'll be pleasantly surprised.

 

[moper]

Hello rather than get into debates about various pros and cons can we hold replies to those who actually have first hand experience with these particular carb please.

I think you've been handed a couple very informed responses. Gale Banks was into turbo and supercharging - I expect that why someone might want a shitload richer mix. As for me - yes - I've run 5-6. Never had any quality control issues. Never needed to mess with any restrictions. Hysteric and YR seem to be dead on it, at least in my less than informed opinion.

 

[Retroboy]

Is this the guy you're talking about?
Who is Gale Banks? | Banks Power

Don't know him personally but his Bio looks interesting. Can you tell us more about the idea and where it came from, was it from a magazine book or research paper?

I had just changed from a 904 clutch auto to a 2 speed trans with torque converter and just couldn't get it right and I was reading something and he said " we have Pro Stock engines in boats that go from idle" and that made me look at how he had these engines set up.

 

[Hysteric]

I had just changed from a 904 clutch auto to a 2 speed trans with torque converter and just couldn't get it right and I was reading something and he said " we have Pro Stock engines in boats that go from idle" and that made me look at how he had these engines set up.

Did he discuss carbs and the calibrations he uses?

 

[Retroboy]

Ran the car on the weekend. .016 restrictors in place, 1/8 holes in the primary side butterfly's. Ran great even while rich at full noise. Still think quality could do with a shake up, I've replaced all 8 threads in the main body for the float bowls and the secondary throttle shaft wasn't installed straight left to right.

 

[famous bob]

Hello. I'm not a novice to engine stuff but can't get this thing to idle properly and it's rich as anything at idle. I have 24 deg timing at idle, 36 total, transfer slots properly adjusted, and .014" stainless restrictors in both idle jets in both metering blocks. I have an EGT probe close to the header flange which is reading high which would normally tell me it's lean but I'm thinking the probe is in the flame so reading high. The air burns your eyes and is stinky as. Bit more info on my set up - It's a .040 over 360 about 11:1 with a Comp Cams solid roller, a Super Victor and a Vertex internal coil Mag. I have a belt drive pump with aHolley bypass regulator with a #70 jet in the return running 6 psi. I'd be happy to have a clean idle at around 1000 rpm.
Anyone used this carb successfully?
Cheers

I alternated one back and forth with an 800 double pumper on a hot 406 sbc in my 92 GMC pick up , had absolutely no trouble out of it , ran a 293 extreme solid roller for a cam too. Truck ran faster with the 800 double pumper, but would get 16.1 miles to the gallon with the 870.
Wish I still had the trukh-------------