Okay. If it's a vacuum secondary carb, the engine will pull what it needs and may not ever open the secondaries fully. The spring tension can be tuned to where it's operating as a 2bbl almost all the time and only start opening the secondaries when the engine's wide open climbing a hill or something.

I like your picture. It does show the manifold fitting just fine over the stock exhaust manifold. How much better would you say your engine runs with that set up compared to original? And how much improvement would you say the Fenton headers added on your '37? I'd like to add the Fentons, but I should probably use the stock exhaust if I'm thinking about turbocharging, that would make the conversion simpler.

I did something similar on my old oil bath filter. I cleaned it out and got a top-breather K&N type 10" filter. On the Holley, I'll probably use the rest of the 10" round filter also.
Thanks.


52 GMC 3/4 ton pickup
68 Big Block Vette
68 455 Firebird