Hey everyone,

First time poster here, with a Sunday project that has inevitably turned into a multi-day struggle. I have a 460 in my 1972 F-250 CS that I am attempting to replace the carburetor on. To my understanding, the 770 CFM street avenger I bought has a squarebore design, each butterfly measuring ~43mm but the intake on my 460, I believe is a D4VE thunderjet intake, it's primaries are only ~40mm wide and secondaries are the ~43mm. I cant seem to find any plate adapter or gasket for the thenderjet's "almost sqaurebore" set up. How do I get these two platforms to mate/ function properly? or do I need to just spend the money on a aluminum intake? Any advice or direction is appreciated.

 

That intake would have been originally equipped with an EGR spacer plate between the intake and carb - note the round hole on the passenger side. That exhaust gas passage needs to be blocked off in some fashion. Best solution is to replace the intake manifold gaskets and use a thin stainless sheetmetal shim on the exhaust crossover passage to both heads (some sets used to come with that shim as an 'option'..Exhaust gasses are very corrosive, and will eat through any aluminum spacer/or adapter plate. OR you can use a four-hole stainless plate under some sort of insulating spacer under the carb. (yes, the crossover carries ~600° exhaust gasses through it!) The Street Avenger has an electric choke provision, so you don't need the exhaust crossover to heat those tubes in the 1/8" metal plate on the passenger side - which is why it is better to block those passages off at the cylinder head-to-intake gasket!

 

His 1972 should have no EGR plate
The EGR systems started by EPA mandate in 1977
Yes, get a different manifold
Yes, plug off the choke heat riser
Have fun

 

His truck is a '72, but Ford never put a 429/460 in that generation of F-series trucks, the only big block options were 360 and 390 FEs.. His engine is a '74 or later engine (D4VE intake casting), but by '77 Ford had switched to spreadbore 4300D carbs on 460s (I've had two! - a '77 Country Squire wagon, and a Marquis, both with 460/C-6s). That D4VE intake is made for use with the EGR spacer - note the hole on the passenger side for the EGR passage.

Ford used EGR systems starting in '73. My current two '73 Cougars with Q-code Clevelands (351C-4V) , and one of my '73 Cougar parts cars with a 351C-2V also had an EGR plate under the carb. The 4V version was made out of aluminum, and the corrosive exhaust gasses really did a number on them.

Even if the OP were to block off the heat riser (and EGR) passage in the manifold, that intake might not seal to a regular Holley 4-hole gasket. Best to use an four-hole adapter/spacer.

Yes, best solution is to use a different intake but there is no reason he can't block off the exhaust crossover passages from the cylinder heads like I had suggested, and use a regular four-hole spacer below the Holley.

 

Duplicate response, sorry