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Discussion Starter #1
Hi all,

the BBF we're building, we had trouble with the ignition. That's now resolved. we swapped to a "normal" distributor (without module). This was done in the past already, but the engine never ran right, so everyone thought that wasn't the problem until I measured. Anyway ignition is fine now, but

to get it to idle at ~1000 rpm (won't run lower) I have to turn in the curb idle screws to about 3.5 full turns (about 3 more than normal).
When i close the idle mixture screws eitehr side it would stall (so there sems to be no blockage there).
once the engine runs past 2000 it seems quick and responsive.

it is like a huge vacuum leak, but we blocked everything off the intake manifold, sprayed it down (no change). So we are currently planning to change the intake back to stock (currently it's a used edelbrock performer).
The only explanation I have is that the intake might be warped or leaking.

Anyone any other ideas before I try that?

thanks a million again!

Kalli
 

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intake gasket could be leaking on the inside. Spraying it down on the outside will not change the idle. If sucking air from inside the engine, one would usually see blue exhaust smoke but not necessarily.
 

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IF it runs smoothly at 1000, a bad PCV, lower intake leak, mis-adjusted secondaries, inoperative dashpot, and vac advance falling-off when idling-down are a few. What (exactly) does it do when the idle goes lower than 1000? Have you done vacuum gauge diagnostics on it?

David
 

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Discussion Starter #5
Thanks all for helping

gasman826: that's what I was thinking. It just never happened to me before. but so far I only did 289/302s ... never done a 460 intake. who knows. That a common problem if not careful?

for the heads I'd have to check again. it was originally a 429CJ, I believe the block was scrap, so they used a 460 Ford Racing block (bottom half), but I believe they re-used the same heads.
I'll see if I can identify which ones they actually are.
your comment: "standard heads and CJ style intake?" if that doesn't match, there's a good chance we did it the otehr way around. I'll check on both

is there an easy way to identify either? I'll check for numbers on car hopefully during the week. I'll google around for that info.
If tehre's an easy way I can phone my buddy and ask him

PSIG:
at 1000 it runs crappy. sometimes completly dies when put into gear. with runing i mean "keeps turning over if left alone". above 2000 there seems to be no problems,
can't be bad PCV (removed and blocked hose towards intake)
lower intake leak: that's something I'll investigate (as above)
mis-adjusted secondaries: I tried with 3 different carburetors (that was my prime suspect). most of the ones we tried are vacuum secondary. I triple checked and replaced the gasket between carb and intake.
dashpot: (there's none)
once I lower the idle below 1000 the engine jst cuts out.
vacuum gauge: I have one but only checked at idle. the vacuum is steady (no up./down or flattering), but very low (about 5-6?)
all testing done with vacuum advance disconnected. Since the throttle plate is so far in (curb idle screw) I already get vacuum on ported hookup on carb. so I disconnected it until issue fixed.
 

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whats the cam spercs ?

lift doesnt matter . cam degreed in ?
 
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