Dumb carb question

[Keoke]

On my car, which is guaranteed to not be stock, but has an original BJ8 intake manifold, there is a paper gasket between the manifold and spacer, in addition to the ones on either side of the heat shield.

Well:

Mine must not be stock either as i do it the same way.

 

[Joe Schlosser]

The original question is what effect the spacer has on the efficiency of the engine. Every engine has a sweet spot for max HP at a particular RPM. This is determined by the displacement, cam timing and the length of the intake runner and exhaust pipes. The intake runner is the overall distance from the carb inlet to the intake valve.
Someone at AH probably sized the length of the intake runner on the dyno. If your engine is stock then the spacer size is correct for the max performance.

 

[Bob_Spidell]

The original question is what effect the spacer has on the efficiency of the engine. Every engine has a sweet spot for max HP at a particular RPM. This is determined by the displacement, cam timing and the length of the intake runner and exhaust pipes. The intake runner is the overall distance from the carb inlet to the intake valve.
Someone at AH probably sized the length of the intake runner on the dyno. If your engine is stock then the spacer size is correct for the max performance.

Excellent point; perhaps why it's called a 'spacer' and not 'insulating block' (or similar)?

 

[tahoe healey]

So size matters here too.