I have run both, but straight linkage has always worked better for me. Careful tuning of carbs, and timing curve will make or break your power and drivability.
409 Cam (mistakes have been made)
- Thread starter 409Steve62
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Since you said one of the rockers came off do you have poly locks on it? If not you may want to check the nuts for a good interference fit, even though they may back off a little loosening the lash they should not back off enough to allow the rocker to come off. If poly locks are improperly tightened the set screw looses contact with the stud and it will readily back off, but stock interference type nuts shouldn't unless they have been tightened and loosened repeatedly wearing down the interference fit.
Check the pushrod holes in the head if the rocker nuts are good.
409Steve62
Active Member
after a night of resetting valve lashes in the shed, went to the auto parts store for some new spark plugs. Fired the old girl up and actually took it for a couple of ok drives with out it stumbling out of the hole and having to rev the tits off it to take off. Its still slightly jerky down low & im still slowly fouling plugs. but its the best its gone since the motor went in the car, alot better than the dyno guy gave it back to me in. then i reset the lashes at 030 hot
It still requires throttle from take off as the gears are too low, but they could be changed.
Timing has been my biggest issue today, its hard to get a steady idle with how the carbs are running. the idle is always up & down (carb & low vac)
I tried to advance the timing to 16-18 with the black stop bushing then it ran like crap & backfired when shut off so set it back to around 12-14 initial and burned up & down the back streets a few times.
Fueling issues are there, i engine gets hot real quick 200+ sitting , runs around the street 190. does diesel on me after a good run at shut down
My neighbors probably hate me as the primary carb linkage stuck wide open and (possibly form me not quite tightening the lock nut enough) and had a bit of a scary moment at full throttle in the shed
i think i may disconnect the 6 AL msd box from the ready to run dizzy, im not sure if its making my life harder at the moment timing wise
im still considering a cam change & putting the afbs back on but it ran good at WOT today. being able to leave an intersection without revving the crap out of her and looking like a tool was awesome. at least one step forward!
Rockers have poly lock, double checked all . We are all human at the end of the day even i make mistakes like today in the shed
It still requires throttle from take off as the gears are too low, but they could be changed.
Timing has been my biggest issue today, its hard to get a steady idle with how the carbs are running. the idle is always up & down (carb & low vac)
I tried to advance the timing to 16-18 with the black stop bushing then it ran like crap & backfired when shut off so set it back to around 12-14 initial and burned up & down the back streets a few times.
Fueling issues are there, i engine gets hot real quick 200+ sitting , runs around the street 190. does diesel on me after a good run at shut down
My neighbors probably hate me as the primary carb linkage stuck wide open and (possibly form me not quite tightening the lock nut enough) and had a bit of a scary moment at full throttle in the shed
i think i may disconnect the 6 AL msd box from the ready to run dizzy, im not sure if its making my life harder at the moment timing wise
im still considering a cam change & putting the afbs back on but it ran good at WOT today. being able to leave an intersection without revving the crap out of her and looking like a tool was awesome. at least one step forward!
Rockers have poly lock, double checked all . We are all human at the end of the day even i make mistakes like today in the shed
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Are you sure the rear carb choke flapper is open all the way when hot and off fast idle cam.Also those small air filters look restrictive . How does it run without them,any difference?
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Food for thought. Instead of setting valve lash hot, I would personally set it cold and set it .002/.003 tighter than the cam spec calls for. Less aggravation and pain! On another note, since the cam may/appears to be to big. Open the lash up to .035 or .040 and give it a hot lap to see if drive ability improves. It should be fine for a test run. Doing so will trick the engine into thinking you just put a smaller cam in because it will be reading less of the lobe. If it does improve its saying "here's your sign!"
Jeff
Jeff
409Steve62
Active Member
Choke flap definitely open all the way, not sure if fast idle cam is included in that? I’ve tried to be a carb expert and failed miserably I did have to put less restrictive filters in those 6 inch pod style edelbrocks air cleaners as it “ran” better on the dyno with out filters so I got those. Just economical for nw
409Steve62
Active Member
I checked it with a gauge on the end of the pump and got 6 psi idling just running with the fuel in the bowl carbs disconnected. Might be time for a regulator to rule stuff out
Look down both carburetors when idling see if you see any fuel dribbling down over throttle plates.
409Steve62
Active Member
Have checked this, it ok. after shut down if i take the air cleaner off there is like a slow vaporing fuel cloud leaving the openings if that makes sense?
Since you have low vacuum you will have to check those metering rods to be seated at idle. If they are not you need to change springs so they say down and pop up under acceleration only.
409Steve62
Active Member
Got the lightest springs in there. They are sitting down at idle but I only seem to get between 8-9 vac
Have you checked for vacuum leaks around carbs . Where is pcv tied in? Both carbs rods down?
Maybe a metering rod change will help 
409Steve62
Active Member
Yeah I have, to the best of my ability . Spraying carb cleaners carefully around carbs… changing vac plugs… it’s been a tough few months with this car that’s for sure
With that cam I don't know what vacuum it should have, others may know.
409Steve62
Active Member
Yeah put a bigger rod in there (dyno guy did) can’t go smaller on the jets as they are jetted with the 1420 jets out of the box anywayMaybe a metering rod change will help
Do you have a chart with those carbs . It will tell you what factory rods springs are in there and what is needed for your engine to be in tune .
409Steve62
Active Member
I do and I’ve tried to the best of my ability. The carbs are 1903 1904 avs2 supposedly for dual setups. They come with the smallest 1420 jet out of the box and the only was able to change springs and go to the largest metering rod