Ram Air manifolds on 7K3 heads
 

Has anyone put ram air manifolds on 7K3 heads. I want to use the manifolds instead of headers cause of the no end holes on the 7k3 heads but some pictures i see of the ram air manufolds doesn’t have the inner end bolt hole. Imagine the pass side manifold. From left to right They have the outer most hole, inner outside hole. Left side inner hole, no right inner hole cause of the sharp turn, no right side inner hole and but has outer right side hole. If that makes sense. So to use the manifolds I would have to make brakets anyway. Did anybody else notice this. Ill try and get a pic. If im wrong let me know.

Sorry looks like drivers side

Pretty sure Paul Spotts makes a bracket for those heads that gives you the outer most bolt holes to attach headers or manifolds to

Oops. Not for manifolds. Sorry!

I ran them on my ‘72 GP. Never had an exhaust leak but I did use two gaskets on each manifold.

So from what i see is on the drivers side the manifold is only going to be held on by only two bolts? The second and third bolt. No first, fourth or fifth. I have no problem making my own brackets but I thought that was the whole point of using the manifolds.

If you grind a bit of a flat where the needed end holes should be you can very carefully start off and drill and tap the area for 3/8" fine thread and use studs at those 4 locations.
Be very careful when you drill the holes and use a bolted up Manifold as a guide.
Shim up the Manifold hole with Brass tubing when you drill so you stay in good alinment

when you tap leave inperfect threads so that you can't bottom out the stud on the head bolt.

I put RA manifolds on my 455/7K3 motor and did what Steve25 suggested. I had the heads off and bolted the manifolds to each head, then drilled all the way through to the head bolt hole. Tapped and installed 3/8" Helicoils and used studs/nuts when I bolted the manifolds on. I put the studs in hand tight until they touched the head bolt, works great. I don't like the "L" brackets, they look like they could bend.

When i get home later I’ll check to see if i have enough material to tap a hole. Also is there a difference between the 64-67 and the 68-72 ram air manifolds or is it just a parts number difference. So can i fit a 68-72 manifold on a 65 chassis or is it a different mold. Also is there a measurable difference between the 2 1/4 and the 2 1/2 manifolds. Seems like the 2.5’s are a little harder to find and about $50-$100 more. Going on my 455, 7k3, roller cam motor, Richmond O/D trans W/3.73 rear. Just a street cruiser.

He does have. Look at the box under the L brackets listed for headers.
http://www.spottsperformance.com/headLbracket
"Head L Bracket (for RA manifolds)
2" Long studs. Set of 4.
#HLB02 ..................................... $75.00 set of 4"

If Bobby's heads don't have enough metal for good thread engagement. And he has to make some brackets. I'd grind on the head and make clearance for a triangle shaped brace to go in the corner of the 'L'. And would probably still make them so they come up just a tad short of the mounting surface. That way if they do try to bend you'll still get plenty of clamping force.

Clay

the only difference I can discern is that the 67 manifolds are 3 bolt flanges on both sides vs. 3-2 on the 68-72. Text I've read on it says there's a change in the "runner design" between them but I can't see what's different. I have 67 manifolds on my 69 without a problem so I can't see why going the other way would be an issue.

Just Because
 

On F body cars it was steering box location that caused fitment issues. 2nd gen (front steer) will not fit 1st gen (rear steer) cars. Now that's with the round port RA exhaust manifolds.

Thinking yall's cars went to front steer in 68. Not positive, just thinking. If so, the older working on newer makes sense. But may not be able to go the other way.

Just something to think about
Clay

okay, I'm only talking from an A body perspective, I don't know crap about F bodies!