I own a 1964 Oldsmobile 394 engine and recently purchased a 3 bolt 3 carb offenhauser intake for it. Now my question is what 3 bolt carbs do you guys recommend? Holleys, Strombergs, Ford? And which model? Please forgive me if this is a dumb question. If I dont ask I will never know.
Those carbs are small for a 394. Try to find a manifold with four bolt carbs, or a two four manifold to let it breath.
I would tend to agree with them being too small for that engine. I'm running 2 straight 97s on a 255 CI and a 259 CI. I once had a 3 bolt Chevrolet 3-2 manifold and discovered that it could be re-drilled for the Rochester carbs. Some of those manufacturers made one casting and drilled it for whatever the customer wanted. Lay a Rochester base gasket on it and see if it can be re-drilled. I think you would be better off in your case.
No. What they are saying is that a proper carb for that size engine in a 3 deuce set-up would be a Rochester 2G series carb (2GC is the center carb). But to make it work you would need to add a fourth hole by drilling your existing manifold in order to bolt up the Rochesters because they are 4 bolt carbs not 3 bolts. Use a 2G base gasket to get the proper hole spacing. Actually I thought their answers were pretty simple, guess that's because I have a Olds 371 J2.
Measure the width of the 394 against the aftermarket manifold. The more I think about this one, the more I think your manifold is for an earlier olds and is to narrow.
You could spend the ca$h for the new Barry Grant 98's....200 CFM each and would bolt right on and no fuel pressure issues. Or Stromberg 48's...@ 175 CFM ea....3 or 'em would probably be close to what the factory carb woulda been..... Remember....alot of these bigger engines had 2bbls from the factory at @ 250-300 CFM....so even 3 97's gets ya to 450......so unless ya plan on buzzin' the motor to 6000 all the time, you don't need a whole lotta CFM.....
Yeah Im not going to be flooring it every chance that I get. Does anybody have any tips on how to tap 2 holes in the intake for some rochesters? Or should i cut my loses and sell this 3 hole intake and buy a 4 hole intake?
What they were saying earlier about checking to make damn sure it fits first was that the small carb setup seems to indicate that it might be accidentally labelled a 394 intake instead of a much more common 303/324 intake. They're close, but the 394 intake's actually wider...
If you decide to re-drill it, be sure to set up the intake so that the drill is perpendicular to the carb gasket surface. The gasket surfaces are slightly slanted to make up for the angle of the engine when it's in it's mounts.
Actually, there is no real reason to redrill for more holes in the intake as the front two now in it will NOT fit a 2G. Just get a trio of Holley 2110's and you will have more than enough fuel going to your motor. I don't want to step on anyone's toes but it is a big misnomer that all you have to do is redrill and tap 2 rear holes in a 3 holer. Not so, as the front holes are not the same as a 97 or 94 and to redrill the front means you have 2 choices........fill the existing holes then redrill and tape or blow 7/16" holes in the front base of your 2g carb. You will see what I mean when you lay the 4 hole gasket on the 3 hole pattern. Just trying to save you a hellava lot of work and grief down the road.
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