Intake issue

[Matt13]

My cast iron spread bore intake won't accommodate my 1972 Spread bore Thermoquad. What am I missing?

[Matt13]

Another pic

[Bullitt-]

 It's not a spread bore intake....

not sure this is a '72 but very much like my '73
https://bluestarperformance.com/product/intake-manifold-3671918-date-9-7-72-a-b-e-body-340-1972-73-used-ships-free-to-lower-48/

[Matt13]

It's not a spread bore intake....

not sure this is a '72 but very much like my '73

My bad then. I thought the larger ports in the back and smaller ones in the front made it a spread bore.

[EV2RTSE]

A carb spacer like this one is also a good idea, if not a necessity for additional clearance and to help insulate the carb from heat soak from the intake manifold.

https://www.ebay.com/itm/265422770254?nma=true&si=4sImEbcR%252BNE6cLhHfrAIIAG1n04%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557

[Bullitt-]

 Found this resource & non-emission '72s use a different intake # 3614025
while emmision models use the same as my '73... main visual difference I see is the choke style..
https://mymopar.com/intake-manifold-casting-numbers/

https://bluestarperformance.com/product/intake-manifold-1972-340-thermo-quad-a-b-e-body-casting-3614025/

[MoparLeo]

The butter fly sizes are different on different sized/years Thermo-quads. The intake manifolds are different between years also. In any event you want to install an insulated spacer between the manifold and the carb base. This helps with gas percolating because of heat transfer from the manifold to carb fuel bowls. Casting number for a 71-72 Thermo-quad intake for a 340 is #3614025-1 not the intake that you have.

[6bblgt]

@Matt13 that's a 1970 340 intake for a Carter AVS - 10/9/69 dated

[Chryco Psycho]

The AVS was also a spread bore but the difference between front & rear was much greater with the ThermoQuad