300 Sniper Install and Core Support Replacement

As she sits!  Core support came from LMC.  Had to do a little custom work with it so that radiator would mount in.  The old radiator perches had to be cut from the old CS and I bolted them into place.  Also, the top radiator mount holes did not exist so my dremel came in handy.

BTW, I have determined that if you decide to "upgrade" to the FI manifolds, you will have to create a custom exhaust "y" pipe or have one made for you.  The one I bought off Rock Auto for an '88 doesn't fit... save yourself the $$ and have a shop make yours.

Drilling a 3.25" hole in the gas tank is a little scary.  Make sure you filler completely up with water if using a tank that had fuel in it. I also used some 30W oil while cutting to fend off sparks, just incase there was a bubble of fuel vapors in there (and there was).

Cool!  A Sniper on a 300 six!  I don't think I've seen one of those done, so am anxious to see what you think of it.

On the radiator support, apparently LMC's support is the 1980 - 84 version.  You can see on our page at Documentation/Cooling Systems/Radiator Support that you have to make mods to an earlier support to fit an '85 or '6 truck.

So, when will you get to drive it - and report back?  

I have to do that exact core support modification this week. I'm installing a 1994 radiator in a 1980. I hope it fits...lol.

My brain was drawing a blank wondering why you had to drill that big hole in your tank, but I see it is for your new fuel pump/sending unit?

Rembrant wrote

I have to do that exact core support modification this week. I'm installing a 1994 radiator in a 1980. I hope it fits...lol.

My brain was drawing a blank wondering why you had to drill that big hole in your tank, but I see it is for your new fuel pump/sending unit?

Yes, I bought the in-tank retro fit Holley fuel pump kit.  It has connections for a return line.  One tip though, if you only have a 16 gal tank the only place you can put the Holley pump is at the rear where I have drilled.  This puts you in a precarious situation when driving downhill for prolonged periods of time with less than a half-tank of gas.  I did a little experiment with a few gallons of water and I estimate that if you are at a quarter tank, you'd be risking starving fuel with just a few degrees of down angle.
So...Holley has a solution.  Of course!  Hydramat.  Well, I bought some but it ain't cheap.  Conveniently, they make a few pieces that mount directly to your drop-in pump.  The youtube videos are pretty neat to watch.

Gary Lewis wrote

Cool!  A Sniper on a 300 six!  I don't think I've seen one of those done, so am anxious to see what you think of it.

On the radiator support, apparently LMC's support is the 1980 - 84 version.  You can see on our page at Documentation/Cooling Systems/Radiator Support that you have to make mods to an earlier support to fit an '85 or '6 truck.

So, when will you get to drive it - and report back?  

There are a few of them out there.  As for mine, I am working on the wiring and then have to get towed to a shop to build an exhaust with a O2 sensor bung in it.  Then, I can start it up for the first time.  Exciting for sure.  I took an Edelbrock 500 CFM 4 barrel off it, put on a 4-2 barrel conversion plate and got Holley's 2bbl Sniper.
I'm itching to get back on the road.  This summer, I pulled the six and had it completely remanufactured with a slightly better breathing cam.  It was down for about a month and a half and I haven't even put 3k miles on the motor yet.

I'll be sure to keep you guys posted.

Gary Lewis wrote

Cool!  A Sniper on a 300 six!  I don't think I've seen one of those done, so am anxious to see what you think of it.

On the radiator support, apparently LMC's support is the 1980 - 84 version.  You can see on our page at Documentation/Cooling Systems/Radiator Support that you have to make mods to an earlier support to fit an '85 or '6 truck.

So, when will you get to drive it - and report back?  

Here you go Gary https://www.ford-trucks.com/forums/1557261-holley-sniper-efi-install.html

Tyler,
So what was the deal with the Y pipe not fitting?
I think that is where I got mine and had no issues with how it fit the manifolds.
Not even where the 2 pipes meet up the hole was big so I did not have to mess with it.
I have heard of some Y pipes that hole is not vary big and needed to be opened up to work.
Dave ----

Dave,
First, I tried to install from the bottom and couldn't get the tail end to clear the transmission mount crossmember.  Then I went in from the top, which required removing my heater core hoses and vacuum lines from the intake manifold and I removed the starter.   The tail end kept getting hung up on the crossmember.  So I cut off about 4 inches and tried again.  The flanges finally lined up....but the end of the pipe was hitting the heat shields on the cab and also the side was contacting the bell housing where the starter mounts.
What a mess....I spent a lot of time looking at and attempting a different approach with no success.  It seems like the first bend with the O2 sensor bung is too aggressive.   The pipe is flattened out in that bend, way more than the IBR...  but I didn't have anything to compare it to.  And Rock Auto doesn't have a person I can explain this to so they want to charge me for another part then ship the old one to them to be assessed.  I thought that since I bought the exhaust for an 88, maybe it doesn't fit an 85 and I somehow missed this in my research.   Whew!
I've already lost the money for the part but would rather drive to a local exhaust shop than get towed there if possible.

Tyler, I'm not certain if the Y-pipe has changed.
*** not sure what pipe you're using there ***

As I remember the one ***Walker 45166*** we put on Josiah's truck fit right up to the manifolds and had no clearance problems.

(I went back and checked his thread on FTE)

I think that's your best bet.  Tell them what's up and that if it is the same then it won't fit and you don't want it.  But if it is bent correctly it'll solve the problem and you will certainly want it.

Hey Tyler where did you mount the lower brackets for the rad? I did the top mounts today but it seems like the rad will be on quite an angle if I swing it inside more...

<quote author="Rembrant">
Hey Tyler where did you mount the lower brackets for the rad? I did the top mounts today but it seems like the rad will be on quite an angle if I swing it inside more...


I thought I had more pictures but this is the only one.  I used the existing holes that lined up with the bracket tack welds that I had to drill out.  On the passenger side (pictured) I only put a bolt in the lower bracket and used the battery tray connector sheetmetal bolt on the top.  I didn't have to drill any new holes in the new core support after making the top radiator mounts and was able to put my radiator exactly in the same place as the old support as far as I can tell.

Also, I had to shave the corner off the bottom of the support sheetmetal in this pic so that it didn't contact the bolt head on the other side of the core support.



And I just snapped this one for you:

After trying to shut my hood, I found that my number of shims required to align everything will have to be adjusted.  BTW, how many shims do you have on the core support bushings on the framerail?  I had 7 on each side...  Now I will have many less.

Tyler,

Thanks for the pics. Is the radiator tipped in on the bottom quite a bit? I mean is the bottom further forward than the top? If so, how much?

Each side of my radiator touches or nearly touches the raised lip of the core support.  Close to parallel with the contours of the air louvers (if that's what they're called).

Perfect, thanks

I don't remember how many shims but it was what ever it took to get the line of the fender to doors straight.
Dave ----

Before the install, I measured the dimensions and it seemed like it would be pretty much a bolt-on.  I recently just figured out that I'll need to correct body panel alignment after the new core support.  ZERO EXPERIENCE.  I have removed nearly all support bushing shims and now the rock guard is just touching the frame rail.  The hood still sits a little too high. (sigh)  Time to learn something new!  
The obstacle IS the way...

IT'S ALIVE !  Fired up the truck last night and performed the first ECU grooming tests and operations.   The throttle response is outstanding.

Big lessons learned  (pictures on page 2 of this thread):

SAFETY FIRST!  If drilling/cutting holes in a fuel tank that has had fuel in it, COMPLETELY FILL IT WITH WATER.  COMPLETELY. Even a small amount of fuel vapor can ignite and become a scary situation.

Make sure to get all of the metal shavings out of the tank. Dish soap and a lot of sloshing and rinsing with water worked very well.

It helps to have help with fuel tank removal and install (should be empty).  Use 2 floor jacks if nobody wants to come over at 8pm on a Tuesday and help you because they have a family, LOL.  

The Mr Gasket 4bbl to 2bbl conversion plate comes with capscrews that are too long for the Offy DP intake mounting holes.  Go buy 1in normal hex head screws and grade 8 washers and bridge the recess where the capscrews would have gone.

The Sniper may not come with the exact fuel fittings you need or want.  Also, it does not come with a fuel pressure gage.  I used Amazon to source these loose ends.

Disconnect your starter and fully verify that you have a 12v source in run and crank BEFORE you cut a wire for splicing.

Rollover valve and grommet: check LMC.  I didn't and paid way too much for a grommet that didn't work and the company won't post my respectfully dissatisfied review (Fillerneck Supply).  $33 for grommet and valve...

Fuel pump block off plate: I bought a beautiful blue anodized aluminum one from broncograveyard.  The included bolts were too large in diameter so I got some from Lowes.  Looks pretty though...

If converting to the Walker y pipe, and you have an Offy intake do not install the intake manifold until the exhaust pipe is in place.  Install order: gasket, FI exhaust manifolds, then the Offy.  I found the Walker pipe to go in easiest from the top, not fed upward from underneath thanks to the transmission crossmember for my T18.

I had to buy 2 y pipes because I didn't go with my intuition when the first one seemed bent too far.  Consider using a different unit like Bosal.  Also I expended 2 hours and 4 grinding bits making one of the holes match the pipe ID for the rear bank.  The O2 bung also had to be cleaned up in order for the sensor to screw in.  There are pictures on another thread in this forum concerning y pipe install.

I have a double belt 1G alternator.  When my lights are on (they are LED) my blinker is very very slow and sometimes fades away when I have the blower running as well.  Looks like my next project is the 3G conversion...

Don't forget that the carb 300s have a different gasket than the FI 300s!

The new core support may require you to readjust fenders and hood alignment.

Junk Yards have cool stuff!  Especially all those little pieces you can't buy anywhere else.

Have patience and enjoy the process!