R-2 Bonnet and Hose

[MikeValent]

What's the inner diameter of the R-2's blower to carb bonnet air hose? Is it 2 3/4"

What diameter air horn does the bonnet fit? Is it 4 1/8"?

[ernier]

I can get you measurements when I get home from work if no one responds. If you are tryng to match dimensions with an aftermarket bonnet the height on all I've seen is too nuch for hood clearance on the Avanti. Also the bonnet will only fit older AFB carbs and will not work on Holley's, Quadrajets or Edelbrock without an adapter which then makes it impossible to close the hood.

ErnieR

[Gunslinger]

I believe the air horn on your AFB is 4 1/8". Current standard on Edelbrocks, Holley's, Quadrajets, etc., is 5 1/8".

[MikeValent]

What I currently have is an 83 Avanti with a Paxton SN2000 that blows into a Paxton air box containing a Holley.I asked the hose ID to see if either SI's Avanti R-2 blower-carb hose, or their flex hose for the Lark R-2 is the same ID as the SN2000 to air box takes. If the hose ID matches my blower outlet-air box intake fittings then one of these can replace what I have on there now.

Since SI also has a catalog listing for the 63-64 air bonnet, I got to thinking that it might be fun to replace the air box and Holley with the bonnet on an old AFB or a Marine Edelbrock with some kind of an air horn reducing adaptor. Or the old AFB top on an Edelbrock - I think I've read posts of someone doing that. I could call the setup a homebrew R-305. Anyway, that's why I'm asking for the dimensions.

[ernier]

I did the AFB/Edelbrock Hybrid...the setup is one of my signature pictures. I think there's more to the marine carbs than just the sealing that makes them not perfect for automotive use. I haven'ty experienced any leaking problems with the 1406 carb and the accel pump seal is an easy installation. BTW, not just any AFB top will do. If you go that root I can tell you what to look for and what needs to be done to make it all work properly.

I'll take a walk out to my shop and measure the bonnet inlet. Back to you shortly.

ErnieR

[ernier]

2 3/4" ID hose is what you would need.

ErnieR

[MikeValent]

Thanks, Ernie. 2 3/4 is what fits the SN2000's outlet, so that's perfect.

Apart from the sealing and vventing, the marine carb probably is jetted a bit richer than the auto version. that would be about it for differences. If I do decide to try this, I'll certainly take advantage of your experience.

[ernier]

Thanks, Ernie. 2 3/4 is what fits the SN2000's outlet, so that's perfect.

Apart from the sealing and vventing, the marine carb probably is jetted a bit richer than the auto version. that would be about it for differences. If I do decide to try this, I'll certainly take advantage of your experience.

From Edelbrock:

For use in marine applications, these Edelbrock carbs comply with U.S. Coast Guard safety standards. Cast surfaces are iridited with Teflon-coated shafts and pump arm for maximum protection. Other features include modified bowl venting, specially designed throttle shafts, accelerator pump seal, 3/8" inverted flare fuel inlet fitting, tube in airhorn for fuel pump vent, 5-1/8" flame arrestor flange, universal throttle lever and revised secondaries for improved transient performance. Note: These carbs have no vacuum ports and are not for auto use. Use our Carb Stud Kits #8008 or #8024 if needed, see page 41.Marine Carburetors For use in marine applications, these Edelbrock carbs comply with U.S. Coast Guard safety standards. Cast surfaces are iridited with Teflon-coated shafts and pump arm for maximum protection. Other features include modified bowl venting, specially designed throttle shafts, accelerator pump seal, 3/8" inverted flare fuel inlet fitting, tube in airhorn for fuel pump vent, 5-1/8" flame arrestor flange, universal throttle lever and revised secondaries for improved transient performance. Note: These carbs have no vacuum ports and are not for auto use.

Besides the extra cost. The Auto Edelbrock I've been using for years has exibited no sealing issues at all and I've had my foot into it plenty of times.

ErnieR