Speed Demon vac secondaires question
Thread Starter
Drifting
Joined: Nov 2003
Posts: 1,874
Likes: 7
From: l In
Speed Demon vac secondaires question
Need a little help choosing a carb for my 383
383 cid
64 cc alum heads, 200 cc intake runners, 2.02/1.6 valves
Comp cams XS274S-10 solid lift cam duration @.050 in. 236/ ex. 242
9.7/1 dish pistons
355 rear gears
400 turbo trans
HEI ignition
Will a 750 Speed Demon annular carb be a good choice for the street?
Thanks
383 cid
64 cc alum heads, 200 cc intake runners, 2.02/1.6 valves
Comp cams XS274S-10 solid lift cam duration @.050 in. 236/ ex. 242
9.7/1 dish pistons
355 rear gears
400 turbo trans
HEI ignition
Will a 750 Speed Demon annular carb be a good choice for the street?
Thanks
Last edited by Phil Zell; Oct 14, 2006 at 12:53 PM.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
I agree with running a 750 - that should make that engine just scream. The drawback to the vacuum secondaries is two-fold: First, the secondary idle speed screw is very difficult to get to on the vac sec carbs. They remove the slotted screw and install a recessed allen-head screw that is hard to see and access. Correctly adjusting secondary idle speed is critical to proper performance on that carb. Secondly, the spring for the vac sec operation is very stiff, and not only delays secondary opening, but never actually allow the secondaries to fully open. Get a Holley spring kit, part number 20-13 (Summit # HLY-20-13) and use the "white" spring. This will allow those secondaries to open up and get you some good performance. Or.... get a mechanical sec carb... Either way, with a Demon, you don't need a choke.
