Holley sniper

[Russtoy]

Hi all, I put a holley sniper on Russtoy, my 69 Charger with a 512 stroker, hughes 232/236 cam, cast 452 ported heads, 727 trans, 2000 stall convert, 356 gears. It runs fine but is down on power compared to the 750 eddy that was on it, I know the 750 was too small, so this holley set up should have been better. My air fuel ratio is 13.8 at idle, 14.9 at cruise and 12.5 at WOT. I just set these AFR and it is better but not as strong. I bought the full holley kit with pump and return line,ect. Anyone have any thoughts? The changes I made did improve the mileage for 6 to 10, I know my mileage will be down from my 383, I get that but it should be way faster. I have a little speed trap on my road, with my 383 I could get 87 mph, with the big 512 I can only get 80 The only changes are engine and converter.

 

[Russtoy]

My speed trap is a rolling 20-25 mph and stand on it for about 600 ft

 

[1967coronet440]

It’s a self learning system it needs time to adjust. While it is known a perfectly tuned carb will out perform a self learning EFI it will Be hardly noticeable.

 

[1967coronet440]

What kind of power are you making with that 512

 

[texas69bee]

Dual plane or single plane intake?

 

[1967coronet440]

Dual plane or single plane intake?

Yup, seen that on engine masters they had big problems when running the dual plane

 

[texas69bee]

Yup, seen that on engine masters they had big problems when running the dual plane

I really wanted to try the sniper. I had bought the electric fuel pump in tank from tanksinc., an extra return line for the efi, installed the o2 sensors. Then I read everything on the Holley forums about the single vs dual, so I bought a quickfuel carb instead.

 

[1967coronet440]

I really wanted to try the sniper. I had bought the electric fuel pump in tank from tanksinc., an extra return line for the efi, installed the o2 sensors. Then I read everything on the Holley forums about the single vs dual, so I bought a quickfuel carb instead.

Good idea, simply doesn’t work with a dual plane, unless you have someone tuning it but the self learning will not work. Unless they have it figured out with a software update by now. I have the fitech 1200 and a super victor single plane

 

[Russtoy]

I have a edelbrock single plane intake

 

[Russtoy]

I am not sure what it is making for power, way more torque then my 383, it will light up the tires at 20-25 mph, no problem, maybe that is my problem, tires slip hahaha. Have actually put over 300 miles on it, cruised 160 miles yesterday.

 

[1967coronet440]

I am not sure what it is making for power, way more torque then my 383, it will light up the tires at 20-25 mph, no problem, maybe that is my problem, tires slip hahaha. Have actually put over 300 miles on it, cruised 160 miles yesterday.

How about some details about your 512, I think the sniper is good to an advertised 650hp

 

[Russtoy]

My 512 is a 440 source kit, 452 ported heads with harden seits, edelbrock single plane intake, hughs 232/236 cam, stainless headers, 1 7/8, 3 in magnaflow out the back, I don't think I am anywhere near 600 hp

 

[1967coronet440]

My 512 is a 440 source kit, 452 ported heads with harden seits, edelbrock single plane intake, hughs 232/236 cam, stainless headers, 1 7/8, 3 in magnaflow out the back, I don't think I am anywhere near 600 hp

Are you sure you’re not just lighting up the tires on the initial punch? I seen a video where they went from a carb to efi and the thing went from a little tire spin off the line with the carb to needing a new set after a launch with the efi

 

[HT413]

Interesting stuff about the dual vs single plane. I'm about to install a new fitech kit on my rpm intake and they say theirs works fine on either.

 

[1967coronet440]

Interesting stuff about the dual vs single plane. I'm about to install a new fitech kit on my rpm intake and they say theirs works fine on either.

I believe it was something with the Holley software

 

[dieseldazzle]

Timing reset?

 

[1967coronet440]

I know it’s a Chevy motor, but it’s an interesting watch.

 

[HT413]

I believe it was something with the Holley software

Interesting

 

[Russtoy]

Timing is 12 at idle and 34 at wot

 

[HT413]

Timing is 12 at idle and 34 at wot

Interesting, the guy who built my 451 recommended 18 initial and go from there.