Avanti fuel injection and 200 r 4 transmission conversion

[bensherb]

I have the sniper on my 427 cobra replica. It works pretty well. If I had it to do over I might just go with a Holley carb.

Why? I'm thinking about going to injection on my GT. I haven't been completely happy with any of the carbs I've tried on it with the crap for fuel they sell us here in CA for over $4 a gallon. Granted, I've only tried the AFB, the Edelbrock and the Holly Demon, all fall short in one area or another (not all in the same place). I havn't tried a good old 4150, they worked good when we had real gas.

[PackardV8]

FWIW, Holley is now on their fourth generation EFI system. BTDT and know first hand, the Holley technical support is only good when the version you buy is fresh on the shelf. In a couple of years there'll be a new one and Holley will tell you, "We don't support your version any longer."

jack vines

[JoeHall]

Why? I'm thinking about going to injection on my GT. I haven't been completely happy with any of the carbs I've tried on it with the crap for fuel they sell us here in CA for over $4 a gallon. Granted, I've only tried the AFB, the Edelbrock and the Holly Demon, all fall short in one area or another (not all in the same place). I havn't tried a good old 4150, they worked good when we had real gas.

Was the Holey a Street Demon? If so, what did you dislike about it? I have a Street Demon, with phenolic bowl on the 56J. Yes, you will not find a more, "incorrect" looking carb to put on a Stude, but its performance is second to none. Even after setting a month, I let the pump run for 30-60 seconds, pump the pedal twice, crank the motor and ir fires up after 2-3 turns, and idles smoothly. NO hot restart problems in the summer. Only complaint is the MPG is as poor as I ever got in the 56J, around 17-18 on the road, IIRC.

[bensherb]

Yes Joe, It is the Street Demon I have. It's currently still on the car, and you are right about it starting relitively easy and running smooth right off. It also works GREAT for putting around town or easy crusing on flat land. It may be particular to just my carb, but it falls flat as I reach the secondaries, a bit past 1/2 throttle, so just going up a hill , that was no problem with other carbs, the car slows to limping by time I reach the top. If I romp on it, it seems as though the secondaries just aren't working, yet the throttle valve is mechanical and I know it opens. I've changed jets 3 times , and needles at least 6 times and it has gotten better but still not right. That's the first issue, the second is if I'm running down the freeway at 70 mph and slow to say 10 mph quickly , which happens a lot here, it acts as if I'm running out of gas. Same thing happens on large "cloverleaf " exits, and when this happens it will buck and sputter while limping along for miles. The only way I've been able to to get it running right again is to shut it off for a few hours; when I start it again it's back to running great. I've heard these carbs often have a problem with floats sticking. Evidently the end of the float can jam against the accelerator pump housing inside the carb and either jam closed or open. I just haven't had a chance to remove and dismantle the carb to check it. Unlike any other carb I've had, on anything, this carb requires total removal to access the screws from underneath in order to get inside it. This Demon carb is by far the best running before getting into the secondaries, but far worse once you hit them. No other carb I've had has had these problems this has.

[JoeHall]

Yes Joe, It is the Street Demon I have. It's currently still on the car, and you are right about it starting relitively easy and running smooth right off. It also works GREAT for putting around town or easy crusing on flat land. It may be particular to just my carb, but it falls flat as I reach the secondaries, a bit past 1/2 throttle, so just going up a hill , that was no problem with other carbs, the car slows to limping by time I reach the top. If I romp on it, it seems as though the secondaries just aren't working, yet the throttle valve is mechanical and I know it opens. I've changed jets 3 times , and needles at least 6 times and it has gotten better but still not right. That's the first issue, the second is if I'm running down the freeway at 70 mph and slow to say 10 mph quickly , which happens a lot here, it acts as if I'm running out of gas. Same thing happens on large "cloverleaf " exits, and when this happens it will buck and sputter while limping along for miles. The only way I've been able to to get it running right again is to shut it off for a few hours; when I start it again it's back to running great. I've heard these carbs often have a problem with floats sticking. Evidently the end of the float can jam against the accelerator pump housing inside the carb and either jam closed or open. I just haven't had a chance to remove and dismantle the carb to check it. Unlike any other carb I've had, on anything, this carb requires total removal to access the screws from underneath in order to get inside it. This Demon carb is by far the best running before getting into the secondaries, but far worse once you hit them. No other carb I've had has had these problems this has.

Wow, sorry to hear that. Initially, the 56J's 352 would stumble if the secondaries were opened much below 3000 RPM, but anywhere above 3000 and it pulled like a freight train. The SD has an air velocity (AV) valve above the secondary butterflies, and a tension spring to adjust when it will begin to open. It's the 2nd set of butterflies above the mechanical butterflies. Max adjustment for the AV is one turn more than the factory setting, and that's where I wound up. Now, no more stumbling because the AV valve will only allow air to gradually flow through the secondaries. Even though the mechanical secondaries will whack open with the throttle, the AV still controls air flow and gs flow through the secondary jets.

I have not experienced fuel starvation under any conditions, nor changed any jets or springs. But may experiment with jetting someday, for more MPG. But really like the performance exactly as is, so probably should leave well enough alone. LOL

If you have not done so yet, I recommend playing with the AV spring setting. If set to max tension, the 289 probably could not pull the AV open below 4000 RPM. But you could dial it down from there, to wherever you want them to come in.

Good luck!

[bensherb]

Yeah, I've adjusted the "auxillery air valve" to it's lightest position to no avail. I'm considering removing it and giving that a try. It was pretty common to do with the carters way back when.

[JoeHall]

Yeah, I've adjusted the "auxillery air valve" to it's lightest position to no avail. I'm considering removing it and giving that a try. It was pretty common to do with the carters way back when.

What I am suggesting is to adjust it to its HEAVIEST position, to delay the mechanical secondaries dumping too much fuel into your motor at low RPM.

[bensherb]

What I am suggesting is to adjust it to its HEAVIEST position, to delay the mechanical secondaries dumping too much fuel into your motor at low RPM.

I guess I missunderstood your statement "If you have not done so yet, I recommend playing with the AV spring setting. If set to max tension, the 289 probably could not pull the AV open below 4000 RPM." I very rarely get over 2500 rpm. To do so I would need to floor it and stay on it, don't think it will even get to 4000 at that, or lock out the automatic shift. Even when I have floored it through 3 gears it still didn't act as though the secondaries were opening. With the AFB it did, but it would fall on it's face off idle, and I could not get that to go away (the Edelbrock was the same). By the way, this is an R1 bored to aprox 298ci.

[PackardV8]

. . . . tried the AFB, the Edelbrock and the Holly Demon, all fall short in one area or another (not all in the same place) . . . . . . . I very rarely get over 2500 rpm.

Then absolutely the last thing that engine needs is a 600 CFM or larger aftermarket 4-bbl. It would be more responsive and easier to tune with a Dave Thibault-rebuilt Stromberg 2-bbl.

jack vines

[JoeHall]

I guess I missunderstood your statement "If you have not done so yet, I recommend playing with the AV spring setting. If set to max tension, the 289 probably could not pull the AV open below 4000 RPM." I very rarely get over 2500 rpm. To do so I would need to floor it and stay on it, don't think it will even get to 4000 at that, or lock out the automatic shift. Even when I have floored it through 3 gears it still didn't act as though the secondaries were opening. With the AFB it did, but it would fall on it's face off idle, and I could not get that to go away (the Edelbrock was the same). By the way, this is an R1 bored to aprox 298ci.

Yes, my point about 4000 RPM is that the range of adjustment is more than adequate for the 289. If you have already experimented with lightening the spring tension, try increasing it to delay (versus advance) the secondaries. Max tension gives a sharp enough contrast to decide if somewhere in between is gonna work. That's just the way my brain works, and maybe hard for others to relate to. LOL. Seriously, adjusting the spring only takes 30 seconds, so not much to lose in playing with it.

In the 56J, I usually shift around 3000, and cruise at 2000-2500. I ran AFB/Edlebrock for years, and liked their performed on 56J, but they seemed too large for 259/289, even the 500 CFM. I disliked the hot re-starts. My favorite carb on 259/289 was the 450 CFM, "baby Holley", model 4360, a.k.a., "Economizer". The first one I stumbled onto was at the LA Winter Meet, in the 1980s. The seller promised I'd like it, and he was right. The hot restart problem was greatly reduced, and it was hard to beat in performance and MPG. Not sure how the Street Demon would work on a 289 for me, but with HFI on both GTs since 2012/13, guess I will never find out.

If you decide to go EFI, there's a learning curve to climb, but I understand the aftermarkets are trying to make the later kits more "idiot proof". I went for several years with the HFI and only recently discovered I had screwed up, "phasing" during installation. (The distributors came pre-phased, but I disassembled them for a look-see, and then improperly reassembled them.) That the cars still ran pretty good that way is a testament to the computer's ability to compensate for tuning problems. Moral of the story is, try not to mess with any of the components, and just follow the directions to a 'T' for installation.

[Buzzard]

Hi Keith,
I posted quite a bit of my experiences with FiTech on this posting: FI Tech in '56 C cab w/ 259

There were several assorted applications we were playing with including Tri-Power on a Chev 383 Roller.
But for the record, I plan on using on my Jack V 308 CID performance motor, a Jeff R custom intake with a Quadrajet mounting flange with a Holley 650 CFM Double Pumper Spread bore and a Racer Brown performance camshaft which I have successfully used previously on my R4 clone. Once underway I'll post my findings.
Cheers, Bill

[t walgamuth]

Why? I'm thinking about going to injection on my GT. I haven't been completely happy with any of the carbs I've tried on it with the crap for fuel they sell us here in CA for over $4 a gallon. Granted, I've only tried the AFB, the Edelbrock and the Holly Demon, all fall short in one area or another (not all in the same place). I havn't tried a good old 4150, they worked good when we had real gas.

Sorry I just saw this. I had a new from the box edelbrock on it... it ran good until I tried to autocross it. When I did a hard 180 turn it would starve. I assumed it was a shortcoming of the carb finally and bought the holley sniper. In getting it to run right we found a suction leak so that may have been all that was wrong with the edelbrock. The Holleys were what they used on the 427 cobras and gt 40s back in the day. …..so maybe that would have been fine for me if we had found the air leak sooner.

I run nothing in it with ethanol too. I recommend that especially if the car will sit over the winter or other periods of time.

[RadioRoy]

I have used the Holley Sniper system . Works well, and simple to hook up. Get the complete system with the fuel pump and lines. Ran a new line, and used the existing line for the return. It has to be large enough to handle the return volume. 1/4" isn't large enough. Only drawback is removing the tank for added fitting.

Wow! Fuel injection and a blower. That car must be a screamer.