Will the eddy 1405/1406 fit the spreadbore intake without the adapter/spacer? That is my main concern I have the same intake as the OP with a 1850 Holley and i really don't want to run a spacer.
The Street Demon and the Edelbrock's have dual pattern baseplates. The question of whether it will work without an adapter comes down to whether the primary throttles can open without interference. Also on some intakes sealing surfaces don't line up. Either case requires an adapter. Short (1/8" thick) plates are sold for this purpose, as well as the taller tapered one like Volksduster showed. As a rule of thumb, the thin ones are not a good method.
In operation and construction, the Street Demon's are similar to the Thermoquads. So why not go with a carb that matches the intake?
