Putting a spacer between your carburetor and intake manifold can often times result in significant power gains as well as improving throttle response and air-fuel mixture. The problem however is determining which spacer type will yield the best results for your particular engine combination. Open hole spacers increase plenum volume and can help extend the powerband. Spacers with holes and tapers can help improve fuel atomization, building torque and offering better throttle response.
To figure out which spacer works best for your engine you minimally need two or three different designs. This can often be a turn-off since no enthusiast wants to purchase three carb spacers to find the one that works best.
ProForm has made things easier with an ingenious new spacer design that combines three popular spacer types into one affordable kit (About $70.) The ProForm Trackside spacer kit uses a 1-inch thick outer frame which slips over the carburetor mounting studs. The included open hole, four hole, or cloverleaf spacer inserts can be easily dropped into the frame to change the spacer type.
You’ll need to replace the stock carburetor studs with the longer studs provided in the kit. Then place a new gasket (supplied) over the studs followed by the spacer frame. 
Note the sides of the frame are marked “UP”. If the frame is installed the upside down the inserts cannot be placed into it.
The desired spacer insert can then be dropped into the frame. There is no need to seal the insert, as a gasket will also be placed between the spacer assembly and carburetor. If you desire greater than 1″ of spacing you can stack additional TrackSide Spacer kits.
The key advantage to the ProForm Trackside spacer kit is in changing out the spacer inserts. The inserts slip right in between the carb studs without having to fully remove the carburetor. 
Assuming you have enough slack in your fuel line, you can simply lift the carb up 1″ and replace the spacer insert as shown.
The best way to test the effects of a spacer is on a chassis or engine dyno. The next best thing is to go to the track and make several passes with each spacer type. More at www.proform.com
Yes, that would be nice to see a real world test of this unit. I guess the only project car for it to go on would be the Torino as everything else if EFI I believe. Hey Fordmuscle can you test this for us?
By ga289stocker. April 7th, 2007 at 12:30 pmTesting at the dragstrip with various styles of phenolic, wood, and aluminum…1″ and 2″ proved out that with my particular combo the 2″ phenolic tapered HVH was the best way to go for optimum speed and et.
By FlashBack. March 18th, 2007 at 10:39 amThe 4hole designs helped the low end, the open style helped the top end and the tapered versions were across the board better.
G.
I used to have the $25 one from Autozone, and it was junk. The inserts didn’t fit well. This one just looks better from the pictures.
By Jimbo. March 5th, 2007 at 6:51 amYes, I agree a dyno test it needed to see gains might be there by using these spacers and where they occur in the RPM range.
By Morgan. February 27th, 2007 at 9:15 pmI bought one like it several months ago for around $25.00 from AutoZone. Looks like the same kit.
By Retyler. February 21st, 2007 at 6:25 pmNow I don’t have to haul my box of spacers to the track, those inserts will fit in my glovebox!
By Jimbo. February 21st, 2007 at 6:10 amSo Fordmuscle should test this out right away so I can tell if I need one
By Tim. February 20th, 2007 at 12:26 pm