[SOLD] 273/318 Offy Dual Four Barrel intake
- Thread starter Mtn Thunder
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So this will fit the later 273/318 heads?
superdart426
Banned
no..not without modifications of the mounting holes
Jim Lusk
Well-Known Member
Depends on what you mean by later...
Hmm, ok the 64 273 heads have a steapear grade where the head and intake meet up.
1965-1969 273; 318-340 all bolt together the same way. Only difference is the intake port openings on 273 and low compression 318 are smaller........
Not sure why the mounting hole would be different
LA heads 1965 and above. 1964 273 and poly 318 this will not work.
Just googled this and summit sells them new for 414.99. These will not fit the 318 without modifications just the 64/65 273.
superdart426
Banned
this is true just fits 64/65 273 unless the modifications are made to the mounting holes
Mtn Thunder
Well-Known Member
I set the manifold on a 340 that has been decked, and everything lines up except for the bolt holes. It is a tight squeeze but I managed to get several bolts started. I would not hesitate to open up the bolt holes to the next fractional size to make this work.
As I mentioned, the port size is 1/4" difference in height and width from a standard 340 intake.
As I mentioned, the port size is 1/4" difference in height and width from a standard 340 intake.
As stated earlier, the angle on the intake face where it mates to the heads is different on the 64-64 273. It will not seal properly if used on a 66 and later SBM.
Mtn Thunder
Well-Known Member
OK!! It's time to make this accurate.
I just took the time to install intake gaskets and a few bolts. There is NO angle difference between the head and the intake. It lines up just as good as my six pack intake. I believe that since I had this block decked, that is the difference I am seeing in the bolt hole issue.
All bolt holes line up and centered. The angle of bolt hole is square to the head.
I agree that there is a difference in intakes for the early engines but in this case I think Offy is off on their description. How many different intakes has MOPAR put out under the same part # and have different configurations to that # ?
I'll leave it at that. If no one wants it, I'll pick up a 360 one day and use it on it. Right now I have a sixpack 340 and a W2 headed 340 so I have no need for this intake.
I just took the time to install intake gaskets and a few bolts. There is NO angle difference between the head and the intake. It lines up just as good as my six pack intake. I believe that since I had this block decked, that is the difference I am seeing in the bolt hole issue.
All bolt holes line up and centered. The angle of bolt hole is square to the head.
I agree that there is a difference in intakes for the early engines but in this case I think Offy is off on their description. How many different intakes has MOPAR put out under the same part # and have different configurations to that # ?
I'll leave it at that. If no one wants it, I'll pick up a 360 one day and use it on it. Right now I have a sixpack 340 and a W2 headed 340 so I have no need for this intake.
pishta
I know I'm right....
Easy guys, MtThunder is correct as there is no difference in the mounting angle of the intake. The early 273 heads used 5/16 bolt holes and the angle of these were slightly different but the difference is taken up when you drill the holes for 3/8 later bolts. You need to use washers under the new 3/8 bolts or the bolt hex catch on the intake during torquing them down. Its no big deal. I ran a performer on a 65 A with the weird bolt size/angle and it sealed fine with washers, also ran one the other way, a Commando 273 4bbl on a later 318, just drilled the holes larger and use washers.
I have this intake on my 340 ,and I raised the intake ports by welding extra alum to the top of all the runners . about 3/8 inch high and back 1 1/2inches then gasket matched them to a 340 intake gasket and went inside the runners and opened them up a little, it worked perfect and yes the bolt were tight . my manifold was new ,block was not decked . I used stainless header bolts for the mounting with 12 point heads. its the one showed in the pic (blue engine)also they sell 2 manifolds /I ordered mine for late style 273/318 heads holes were 3/8 inch with correct angle, they might just drill them out to fit. both have same casting # I port matched it to the 340 gasket but there wasn't enough room to hold the gasket ,it was thin around #1/3 so welded it up on all ports so I could shape the runners better.(the one pictured looks like mine with the late bolt pattern, with larger holes and bolt angle. (also with fit/alignment on the bolt holes being too tight I found if you use a steel intake gasket the manifold fit ,with felt-pro/ victor style about .060 /.040 it raised the manifold up making it hard to alien the bolts. I think they made the manifold to thick/too wide on the flange sides . so you can machine it about .020 on each side or just drill the mounting holes larger .)
How about three LD4b's?
va-mopar
Well-Known Member
Mtn Thunder Is this Offy 5488 intake still for sale? if so, what is the rpm range? I have a 360 bored 30 over with J heads... would this work on it? and if so, what carbs would have to be used? Thanks' in advance.
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