This is supposed to be a 1971 455 in a Riviera. What is that thing on the intake next to the valve cover that runs the length of the intake? It looks like a tube or something. My intake does not have this.
Yup, my '72 engine has the same thing on both sides of the intake. Supposedly, it doesn't hurt anything. o No: but the '71 manifold has a cleaner look.
In a word, NO I may be wrong here but it might if it were a late year build and the factory was out of the non-smog type manifolds. Did your X have a smog pump on it?
That intake is either a 73 455(with an air pump) or newer or could have been ordered on a 1972 California emission equipped car.If the distributor is the correct one,it is not a 74 or newer.They would have had a HEI distributor.If you notice about 2/3 back,they plugged the top of the tube where the fitting was that hooked to the AIR pump.Also,notice the EGR valve to the right of the carb under the hose.And NO your 71 X didn't have that either so it wouldn't be right. Pat
The intake I have for my 73 has that and it is UGLY!! If I find one at the right price, I may put an older one on there just so I don't have to look at it! It really is a GOOD way of doing the air pump compared to the rust prone external metal tubes used on most engines. I have heard these are some of the hardest parts to find when doing some restorations because they usually ended up taken off and thrown away!! Ken
Yep, air pump passageway. Started in '72 (except for Stage 1). Air from the A.I.R. pump is sent to the exhaust chamber to inject oxygen to help complete the burn process of unburned hydorcarbons. While definitely not an attractive setup and adds to clutter, it's also probably the least intrusive emission control.
A earlier intake will not fit on the smog type heads. This because the earlier intake will not block off the air holes in the heads and the heat cross-overs have such a different shape that they also will not be completely covered by the intake. I also wondering if this smog type intake is realy a flowkiller. Sure you can grind the tube a bit in the intake runners (not to much!!) Bram
Some people just block it off. It's not intrusive and there was no change in performance from '71 to '72. If you really dislike it, get a set of '71 heads and intake. Quite honestly, it has zilch to do with performance - just an isue with looks. Air pump blows into exhaust ports, but in '73, they introduced E.G.R., which definitely DID have an effect (zapped 20 horses, or so). By the way, my understanding is that the the intake manifold, even for '72 with the A.I.R. is the best manifold for low end torque. The Edelbrock B2B is a great choice if you want to cut some weight, but I haven't heard that it adds that much to performance. I think Adam Martin runs a B2B, but he has a '71, which was pre A.I.R. I left my A.I.R. system intact for originality, and I'm not complaining about performance.
I believe they make a B4B which is suitable for post 72 motors...basically, the flange covers up the AIR holes. Oh, when I switched to the B4B, I was able to squeek out some 2nd gear chirps from the rear tire. Of course I can't do that now, since I've added a posi. It takes some power to get them to rip in 2nd gear. And a shift kit..
Gee, I feel better...my 350 LeSabre will nearly always squeal the right rear when going to 2nd...but I've got a shift kit...and the posi is still in the barnwith the '72 455 (with AIR manifold). o No:
Yeah, since I've put the posi in, I haven't been able to scratch in 2nd. The shift points and stiffness of shift makes a big difference though. I am probably gonna get a shift kit, since they're so cheap...plus adjust the vac monulator to shift at a higher RPM. That should help it out:Brow:
Yup, shift kits work well, but be careful, you can overdo it, and some kits just screw things up. I forget which one I did (15 years ago), I think it was the B&M kit, I went for the "RV" (lightest) setting. I like it, it's not harsh at light throttle, but at wot, it GRABS the next gear something fierce! :3gears:
This air passage has a corresponding bump down into the top of the intake port in the manifold that does impede air flow. All 72 big block intake manifolds have this passage with no EGR, 73 has an EGR valve along with this passage
From what I have read in the past, the heads with these holes are just as good as the 71 heads. I think any of the heads, 71-73 will perform the same. I think I read where someone poured the holes full of molten aluminum and smoothed them out where they enter the port and the flow made no difference at all. I have the 73 heads and if I use them, I think I'll just plug the holes with some pound in style plugs like a freeze plug with some JB weld on them. That way, no matter what intake I use, these heads should work OK. I think the exhaust crossover has also been blocked off with the molten metal trick but I guess the old steel shim material would work too. If I was working with a build up that didn't have to be kept stock and money wasn't an issue, I wouldn't even mess with the steel heads these days! Ken
I blocked the EGR and AIR passages on my 72 455. Just made small plates out of 1/4 inch steel. When the motor has a fresh coat of paint on it you really do not notice the runners. I added a TRANSGO kit to my TH350. Nice shifts on light throttle. Spins 2nd gear and will even chirp 3d on a good day. Stock motor, Mild cam, 3.23 posi JP
