When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I recently bought a 71 F250 camper special. I found out it has a 1961 Thunderbird four barrel intake manifold and according to a friend o the holy on top of it was a ford version. I remove the holy and installed an Edelbrock performer 1406. Earlier pictures I posted someone noted that I had a spread bore to square bore adapter and that it may cause issues. So I have purchased a square bore 1 inch spacer. I'm wondering if it's even needed and if it is I have two ways to install it and I'm hoping someone with more experience could chime in with their thoughts. Should I use the four hole or the open insert? Or do I even need a spacer?
What you have there is a spread bore adapter for an open plenum manifold. The correct adapter should have been a 4-hole spread bore adapter. Just to note, a 4-hole square bore adapter is OK for use on an open intake plenum but not vice versa.
I suggest a 4-hole square bore adapter for your 4-hole square bore intake... one-inch max.
Ok. I'll switch over to the square adapter pictured using the 4 hole design. Is there any need for a spacer if my linkage works without? Also regarding jetting I'm hearing the extra space between carb and manifold might require larger jets.
Ok. I'll switch over to the square adapter pictured using the 4 hole design. Is there any need for a spacer if my linkage works without? Also regarding jetting I'm hearing the extra space between carb and manifold might require larger jets.
My 70 (360FE/TKO) has a one-inch spacer and no mods to the linkage was necessary but it uses a Dentside linkage... no funky 'trapeze" set up anymore.
Yours should be okay.. the angle change isn't significant.
I don't think a 1" 4 hole spacer would require fatter jets. Headers and a high flow exhaust system yes. I don't have a 360/390 in my rig, but I've read on here numerous times that they like the spacers for more power. Spacers make the intake track from carb venturi to intake valve a bit longer. Which changes the power band. Mini version of a Tunnel ram intake or the 60's Chrysler Cross ram intake. To an extent, the longer the runner the higher away from idle the power band kicks in.
