Holley Sniper on 1963 Cadillac

[Ben Bright]

I am looking to install a Holley Sniper Master Kit, and mechanical fuel pump and fuel line on a 1963 Cadillac two door hardtop sedan.
Has anyone here ever done this before? and have any possible suggestions?
Thank you

[V63]

The fuel injection would be an electric pump either intank or rail pump. I blocked off the exhaust ports thru the intake ...see olsons gaskets for those.

 I prefer to eliminate the engine clutch fan and opt for a flex fan.

[TJ Hopland]

The fuel pump/tank is one of the common problem areas.  Other than that it seems to be wiring and workmanship issues.

I have not looked close at the Snipers recently but I assume the master kit has an inline pump?  Inlines seem to be the loudest and have the most issues.  If you can find a way to do an in tank that seems cause the least amount of issues.  I don't think anyone makes an EFI tank for any of the Cads but GM tended to have a lot of similar shaped and sized tanks so if you know roughly what yours looks like have a look at what a place like Tanks Inc has to offer.   I got a tank from something like a 66 Biscayne in my 73 Eldo. It was almost a direct fit.   

[fishnjim]

One option maybe to call Holley and see what they say, albeit they're selling.
Trying to find that one needle in the hay stack that's done this is better done on the modified page, too.
I don't see any problem if it's done correctly but more work than a simple bolt on.

[mario]

Ben:
You might want to check this out...

https://www.summitracing.com/parts/edl-36032?seid=srese1&gclid=Cj0KCQjwxIOXBhCrARIsAL1QFCZ4QSsWBRcuxJo3_a25mUS8c0lpgcH4nv1oDHkTiMdMYRr828QBFVMaAlFvEALw_wcB

It gets fed by the factory fuel pump, pressurizes the fuel, then feeds the sniper.  It is an added expense; however, you keep the stock tank and pump.
Good luck.
Ciao,
Mario Caimotto

[V63]

I forgot that option🤦🏻�♂️...mostly because I would not consider it. Mechanical pumps and alcohol blended fuel is just too problematic.

[TJ Hopland]

I ran fuel pump thing similar to that and they are not the perfect solution people hope they are either.  There is a reason 99% of factory systems use and in tank pump.

[mario]

I have installed this in my 49 sedannette tank.

Holley In-Tank Retrofit Fuel Pump Modules 12-133

Was a tight fit and had to dimple the bottom of the tank to add another inch to the depth of the tank. It is feeding the holley xp. The hydromat gets me down to 1 gallon in the tank.
Ciao,
Mario Caimotto

[79 Eldorado]

I installed a Sniper Stealth on my Chevelle. I created my own sending unit from a new stainless stock sending unit. I added a pipe to send the return down so it exits very close to the bottom of the tank and I added a Holley hydramat. The hydramat is very expensive but they are amazing. There's a PN with an elbow which worked great. I essentially have the pump laying on it's side.

I remember seeing a master kit. I would compare exactly what extras you are getting and if they're really the parts you want to use. To get a clean install I ended up extending nearly every wire in their kit. For some I bought replacement terminals and seals and I made my own replacement wires; others I soldered and extended. The relay and fuse for example would need to be located very close to the TB with the wire they provide. I wanted my fuse close to the battery and I wanted to hide the relay and fuse behind the headlight and in front of the battery. I ran my wires through the inside of the fender.

Holley does make a sending unit for some cars with a regulator on the sender. That wouldn't support the combination I have and I didn't want another part which could go bad in the tank. I ended-up mounting an Aeromotive regulator to the place where the mechanical fuel pump normally mounts. That meant I needed a return line which was larger than the one I had.

I built a very nice adapter to quick connect an air line to the AN fuel line fittings with a gauge and ball valve for checking the system and setting the regulator before it ever saw actual fuel. Looking back that was a very good idea as I found some really small leaks and at least one I couldn't believe which turned out to be due to an undersized 1/8" NPT brass plug.

My install cut no corners but I easily doubled the initial purchase price of the Holley kit. One reason is because if you match the color of each wire you'll find that you end-up with a lot more than you need for one car. I also found myself buying fittings for multiple options of doing the same thing. Sometimes when you get into a job like this the best way isn't always initially obvious. That's partially because some fittings you would ideally like are difficult to find. I also ran into some other unexpected issues.

If you need any photos of the parts of my set-up I could post them. I can say that I was glad I got inside the Holley wiring harness because I found some poor connections and one piece of shrink wrap which they forgot to heat/shrink. My IAC internal wiring was also routed incorrectly.

I'm very proud of the finished job but each time I thought I placed the last order I needed something else and the cost kept growing.

Scott

[jwwseville60]

Ill be the cave man Luddite here......

Three excellent professional old car mechanic friends all removed their complicated EFI units and went back to carbs and return lines with an electric pump. (1960s GM cars) They said the time and effort to get it all correct and then keep it that way wasn't worth it. These guys know their stuff.

GM spent untold millions on their modern EFI systems. Given all that LS reliability, putting on a 2500$ "kit" on an old engine is fraught with pitfalls. Have a resto-mod or street rod? Go for it.
An old Caddy? Not me. Too fiddly and fussy.

My suggestion is to save that money and R&D hassle and go for an Edelbrock carb, return line and good quality electric pump. Insulate your engine bay fuel line too. Pertronix will help. (Keep a spare kit in your trunk bag.)

Just because we have modern whiz-bang technology doesn't mean its good for all applications.

No more universal "kits" for me!
All my Caddies run fine, even in humid 95 deg heat.

[TJ Hopland]

John, what vintage were your friends systems?  There have been some real ups and downs with the kits over the last 15 or so years.  A lot of the earlier stuff was quite a lot of work to get and keep running.  Around 5 years ago seemed like a turning point especially for the basic TBI systems like the FiTech Go line and the Sniper.  I think FiTech grew too fast and Sniper was rushed so both of those started having issues especially with the 'supply chain' issues.             

[jwwseville60]

TJ

They installed them in the last 5 years.
I had a 2018 sniper and took it off.

Honestly, 15 years ago they said it was perfected.
But it wasn't.

This might be helpful:
https://www.youtube.com/watch?v=WQx_h5D8PPM

https://www.youtube.com/watch?v=OunZHPaAvgM

Sorry to be a wet blanket, but wow...

[jwwseville60]

Wow....

[TJ Hopland]

What issues were you having with your installation?  As someone who has done a few systems I'm curious but I'm also sure others considering a similar system would like to know what issues you had.