Holley Sniper

[dwomby]

Thanks for the detailed results.

I think, given our lower US full prices and my low annual mileage, the investment is not worth it to me. I will keep tinkering with the carb and Pertronix ignition once I get the car back on the road.

David

[David C]

Great to hear all well. Thank you for taking the time to share.

[David C]

I have just spotted that Holley have released the Sniper 2 EFI kit. Hopefully this deals with most of the issues they had with the original. Really tempted now but will wait for a few home user reports.

[Green411]

It will be interesting to see how much of a real improvement the Sniper 2 offers. Do let us know if you get one, and what it's like. Although my first one failed (dead ECU after an hour or so's total running time from first start) I get no interference issues with my Sniper, for instance, and the basic connections are genuinely easy to follow. Possibly the major new thing is easier connection to their electronic distributor?
I haven't got to that bit on mine yet - am still using the stock distributor albeit with Pertronix kit installed. I haven't even mapped the advance curve yet.....hmm.....perhaps I should stop typing, put my laptop away and get my timing light out..........

[David C]

I think you definitely should!

I'm not sure about the 411, but the Poly engine in the early V8s has the distributor at the rear of the block so I don't think interference would be a big issue. Ford engines with the distributor right next to the ECU seemed to be the worst offenders.

The big issue for me was the number of reports of failed ECU on the original Sniper. I very much hope version 2 is more rugged. V2 also supposedly has improved throttle geometry.

The main reason I am considering a Sniper is that fitting overdrive brings the engine speed so low at motorway cruising speeds that a standard distributor doesn't have the timing range to cope. Also the Weiand inlet manifold that I have presents mixture issues at low RPM that are hard to accommodate with a standard carb and distributor. These are both marginal issues but adding a Holley Hyperspark controlled by the Sniper should bring everything into line. Add a decent tubular manifold with ceramic coating and I very much hope to have an original engine and nearly original transmission with the drivability and economy of much more recent cars.

[Green411]

Re using a Holley Hyperspark distributor: the Sniper 1 can drive the Hyperspark but I can't remember how easy the connections are. Or you can lock out the mechanical advance on the stock distributor and get the Sniper to run that. In both cases you tell it to run the distributor in the hand-held terminal's base settings menu.
Re throttle bracket geometry, Holley sell a small Mopar/Chrysler extension bracket, (Hly-20-7) which I used, to get the geometry right. Apparently Torqueflites use rods & bellcranks for managing the upshifts and kickdown and the added width of the Sniper vs a carb, plus a bit more still from the adaptor bracket meant that it seemed best to get a new top rod (the cranked one from the throttle bracket to the top bell-crank) made. This was a mirror image of the original ie the bend was in the opposite direction, but it was the same length & number of threads. It took a bit of internet research followed by a bit of playing about to get the adjustment right. Probably easier if you remember to count the visible threads on the stock setup first, which of course I forgot to do!....d'oh....

Here's a list of all the parts I used - hope it helps:
Holley: Sniper Classic gold (550-516), Drop-in Returnless Fuel Module with 255 lph pump and Hydra-mat (12-131), throttle lever extension for Chrysler (20-7);
Weiand: sealing plate 9006 for spread-bore manifold-to-square bore carb/Sniper;
Felpro: intake/lifter valley pan with blocked exhaust heat riser 1214;
Merlin Motorsport: 1/8 NPT Smiths temperature gauge sender CB-TS-18;
Bespoke: top throttle rod in mirror image of original
Bespoke: exhaust diverter housing on UK driver's side between exhaust manifold and downpipe
Small assortment of -6AN (9/16 UNF) and ¼ NPT blanking plugs and hose barbs; ¼ NPT-to-1/4 BSP adaptor if you use existing fuel feed pipe which came from the main/reserve valve; 2m of R9 fuel hose; 6 good quality efi fuel hose clips; can of Chrysler Orange engine paint; assorted gaskets; lots of tea. Then more tea. Total cost was c.£2k.

[David C]

Really useful information, thank you.

I have done a bit of reading about it and there seems to be general agreement that it's a good idea to have a post pump filter even if you are using a Hydramat.

I'm torn as to whether to go for the Hydramat. It looks brilliant if making a tank from scratch but since the Bristol tank has baffles and a sump I wonder how much advantage it gives. I think the size you have chosen along with how often the car is used will give a good few years before it clogs but I'm more inclined to let some of the small particles go through the pump and collect in a 10 micron post pump filter that can more easily be replaced. By no means a criticism of your choice. I may well decide on a Hydramat but haven't made my mind up yet.

My shopping list currently looks like this:

Sniper 2 550-510 3xx $1300
Hyperspark distributor 565-344 $400
Fuel pump 12-169 $490
Coil 556-153 $45
Filter 162-554 $120
Filter brackets 162-574 $45

Total $2400

These are not confirmed choices that will definitely work together, just the best I can do for now after a bit of on line research. I am waiting to see how well the overdrive gearbox conversion works. If it's a success I think the Sniper will follow soon after.