The Stovebolt Site Forums The Shop Area Engine Shop edelbrock dual intake on 235

Hello all,

I'm in the process of trying to install an edelbrock dual 1 barrel manifold onto the 235 engine in my truck. So far, I've run into nothing but problems and I was hoping someone here might be able to help.

First of all, the edelbrock intake manifold bolt holes - the ones that the exhaust studs would come up through to bolt the intake to the exhaust - are wider than the existing studs. (Weird. I'm beginning to wonder if this intake came off a 235 at all.) So my plan was to remove the existing studs and drill and tap the exhaust in the right places.

But once I got the old studs removed (OK, OK, so I broke them off) and test-fit the two manifolds together I found a new problem: the intake doen't even come CLOSE to fitting up to the stock cast-iron exhaust. With both in place on the engine the two manifolds touch at the firewall side of the exhaust heat flange and have 1/4" of space on the other side. The angles here are way, way, off; In fact, they interfere so badly I would need to grind down some of the exhaust to get the intake to sit correctly against the head. Is it possible for the exhaust manifold to be that warped or am I missing something here?

Right now I'm leaning towards grinding the exhaust down so it's out of the way and trying to find someone to weld a block-off plate over the old exhaust heat port. Anyone have other fixes?

Thanks,
Keahi

Does the intake line up with the ports in the head OK? If it's that far off in relation to the exhaust, I wonder if it's worth the effort to make it fit? Multi-carb setups look cool, but they're a royal PITA to synchronize. If you can get the performance you want from a single-carb setup, don't even consider 2 or 3 carbs. A big 2-barrel with similar CFM to the duals will perform better, and give you a lot fewer headaches. I've done a considerable amount of work with 2 and 3 carb setups on marine applications, and a good single carburetor will work better every time!
Jerry

Thanks for the advice! The intake does line up with the head ports, so I'm not sure what's going on everywhere else. I'll also keep an eye out for a single carb intake, but in the meantime I still need to get something working. I'd like to be able to put the stock intake back on but I think I've butchered the stock exhaust to a point that it won't work.

Keahi

Some of the aftermarket intakes (clifford, offy, etc) arent meant to work with stock exhaust manifold. Most 235 "go jobs" ('50s hotrodder slang) used split manifolds or the fenton headers with custom manifold clamps to fit correctly.

Hotrod,

I agree with you that the more carbs you have, the more problems you might encounter. However, I haved synchonized multiple carbs on VWs and English sports cars that had separate intake paths for each carburetor. Most multicarb intakes for 216/235/261 engines have the carbs mounted on the same (shared) intake path/journal. In this type of set-up, are you synchronizing the carbs or just trying to equalize adjustments of idle speed and mixture (tuning them)?

Maybe my understanding of the term "synchronization of carburetors" is wrong: balancing the fuel intake (actually the fuel combustion) in each cylinder (or each pair/set of cylinders).

Nonetheless, no matter what the terms refer to, and no matter that a single-carb intake might not have the same appearance as a multi-carb intake, I agree that a single 2 or 4 barrel carb would be easier to install, set-up, and tune (and would most likely run more economically).

Tim

I started out working with 3-carb setups on flathead F_rd V-8's on 1/4-mile round track cars, running Stromberg 97's and alcohol. No problem with idle or midrange settings, because we were either wide open or off. On a street engine, the throttle plates must be synchronized exactly, to assure that all the carbs on a single intake plenum get equal venturi velocity. Otherwise, one carb will go from idle to midrange before another, creating rich or lean spots in individual cylinders. Ditto on power valves. On the old Buick and Hudson multi-carb engines, the second carburetor acted like a 4-barrel, going from closed throttle to wide open in a very short time, and those ones had no idle or midrange system. The second carb was for wide-open operation only. The Corvair 4-carb system, and the Pontiac and Olds 3-2 setup worked the same way, with the secondary carbs being vacuum-operated at full throttle. With 2 or 3 times the parts to deal with, the possibility of problems increases exponentially. My Suzuki GS550 motorcycle has 4 carbs, one for each cylinder, and must have all the throttle plates synchronized, plus idle adjustment for each cylinder. That's an all-day job sometimes!
Jerry

Going to have to disagree in some areas on this thread. Comparing PROPERLY SELECTED multiple carbs to PROPERLY SELECTED single carbs:

Ease of installation - definate edge to single carb

Cost - definate edge to single carb

Problems (after installation) no difference or a minute edge to single carb

Power - definate edge to multiple carb

Fuel economy - edge to multiple carb

The only way a single carb is going to beat the performance (both power and economy) over multiple carbs (remember - properly selected) is on a single cylinder engine.

The major question becomes: Do you want the look, power, and economy of the multiple unit badly enough to spend the time to do it, or to pay someone else to do it.

Jon.

Getting back to tkeahi's problem - right off the top I would say you have either a 216 Edelbrock intake with your 235 exhaust, or , possibly a 216 exhaust on you vehicle. :confused: Don't think it's impossible! PO's change things out and those parts can be interchanged!

I have just completed installing an Edelbrock on my 261 and discovered in the process that the intake was a 216 intake. Needless to say, it would not match up to the 261 (like a 235) exhaust. The studs are spaced differently, the angle of the match up of the two pieces is different and there is really no way they will fit together.

Base on your description of what's going on with your project, I would say your "235" intake is really a "216" intake. Betchya!

I would suggest you find out what you have got first and, if you want to use the Edelbrock, get the proper exhaust manifold, or Fenton headers , to match up. You can still find some Fenton headers available with a "heat box" in the "Parts For Sale" of this site or EBay. You can always use Fenton headers with a "tube" set up for heat.

6cylindersovertexas,

I think you're right! I knew I was missing something here. I'm new to these engines and didn't realize the 216 intake would be that different from the 235. Unfortunately, there's nobody I can really ask to see if it was meant for a 216 - my father bought it from a guy who claimed it was for a 235 and that's as much as we know.

I had a muffler shop weld up the exhaust heat riser hole today - I'm thinking that Hawaii weather should be warm enough, huh? Then my father and I finally got the intake and exhaust on the truck, and lo and behold it fired right up and idled better than it ever has before.

I still have some details to tweak: the throttle linkage needs to be adjusted and one of the column shift rods hits the intake, but it looks like it should all work out. Thanks!

Great tkeahi! I knew you could work it out! All you got to do is "want to do".
Good luck!!

Glad it is working out for you. I think you will like your setup.

Jon.

Good job on the multi. carb set-up! any in-line just lookes RIGHT with more then one :p . lol. and i agree, they are a pain, as i plan on doing a 2x1 for my 250, but..i'm willing to sacrafice the time to do it, for the look and fuel economy.

once again, congrats, its good to hear about thigns going right for pple..it gives hopes to us all!

Later. SamWise.

Good job on the multi. carb set-up! any in-line just lookes RIGHT with more then one :p . lol. and i agree, they are a pain, as i plan on doing a 2x1 for my 250, but..i'm willing to sacrafice the time to do it, for the look and fuel economy.

once again, congrats, its good to hear about thigns going right for pple..it gives hopes to us all!

Later. SamWise.

Yes, I agree with that 6 cylinder Texas guy, 216s and 235 manifolds are different. Easy way to tell a 235 intake, looks like a big gorilla twisted the thing vs the straight 216 unit. Also the intake runners on the 216 are a bit smaller. I used a 216 dual intake with my 261 for a long time, with Fenton headers. These manifolds will interchange 235 to 216 as long as you stick with the same intake AND exhaust, as a set.

Temporary fuel lines and the exhaust still needs to be hooked up...

[img]http://img.villagephotos.com/p/2004-7/772736/carbs005.jpg[/img]

Keahi

Wait... I thought the port diameters were smaller on a 216 than a 235. Meaning the intake rings for a 235 wouldn't fit the 216 manifold???