it appears the overall width of the 454 TB venturi is wider than the width of the weiand manifold top mount width by about 3/8 inch. the adapter plate is exactly the width of 454 venturi. so the air/fuel flow will hit the top lip/mating surface of weiand manifold and apparenly puddle on lip. idealy the adapter plate (1/2 inch) should have been machined for the manifold width to be less than the TB width at that small eliptical area. but that is custom machining and each application is different.

maybe this is no big deal? comments...

 

That is a typical problem and a little fab work to the intake is necessary. A machine shop should be able to modify and radius the intake inlet.

 

that was my only thought. BUT the gasket surface is soooo limited. if i cut out eplitical 3/16 by say 1.50 inch thumbnail with dremel( manifold mounted with new felpro) i may be in danger of a vac leak as that is about 66% removal of manifold gasket surface at edges. is this really a big deal keeping in mind the old plenum xram had terrible fuel distribution/ puddling and convoluted passage into manifold?

 

Ron,

I made my own adapter and I didn't bore out the side that hung out. I left a flat and then put some bevel into the adapter and some bevel into the plenum. That way the gasket area was not reduced too greatly. You could have a welding shop put a couple beads of aluminum filler into that side of the bore and then grind/file it to the shape you want.

 

now that is a good idea. i have machine shop that i did biz with that can most likely handle it and do it right..

 

Ronny, you could have the machine shop just make you a new adapter that has the bores at an angle so as not to overlap the top of the manifold, or have someone weld up the adapter you already have an then recontour it to not overlap. I would also contour in between the bores to give you all the room and flow needed.

Steve

 

do you think it worth the bother and cost? the area is about 1/8 to 3/16 inch by 1 3/8 inch long. i bet $50-$100 cost.

 

Take a dremmel rotory tool and contour the invading areas on the intake, you don't have to go the limit but any thing you can remove would help. I have the same problem on my rpm airgap manifold. I'm like you I don't want to remove anything I don't have too.

Steve

 

The holley adaptor I use is about .75" thick and it its cut at an angle so the tbi sits on it fine, but the bottom .50" is just open, not the 2" bore of the tbi, so the bottom fits square on the edelbrock intake, thats how they get around the problem. Look at z28boy.cz28.com 's website he has a picture of his air gap with the sides machined to accpet the 2" tbi with a flat 2" plate. Hope that helped...