Have you put a vacuum gauge on engine and tried this test. With it idling slowly rev engine and hold at a little higher rpm and see what vacuum does. See if it gets higher and stay there or does it stay lower.
409 Cam (mistakes have been made)
- Thread starter 409Steve62
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409Steve62
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Higher & stays till it gets to a certain point then will drop off. If I raise the idle it will raise the vac
What are you running for fuel?
On the quick high acceleration does vac drop and hang there.when driving once you accele hard does it keep going or just bog?
409Steve62
Active Member
100 octane. Yeah vac drops
Did it perform better on Dyno then in the car??? If so is your exhaust good??? Have you tried with open headers? Neighbors get ticked???
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409Steve62
Active Member
Did verify tdc. Has sbc balancer and spot welded tag in correct position on timing cover. It’s seemed to run better on a rolling road dyno with no load on . The issues started happening on the road test. 60% resolved today drivability wise but all round dyno kind of got me half way there with the carbs
409Steve62
Active Member
Exhaust 2.5 with flow masters , yip ticking the neighbors off
Oh I thought engine was out of car on Dyno test. My misunderstanding.
So what did Dyno test show??
409Steve62
Active Member
Before dyno I comp tested with 160 all round
Dyno did the test in 3rd gear 
told me I have 300hp with 750 nm .. so yeah . I need a new dyno guy
Dyno did the test in 3rd gear
told me I have 300hp with 750 nm .. so yeah . I need a new dyno guy
Take a piece of hose, with the engine idling take one end of the hoes and hold it to your ear and the other over the carburetors one at a time see if they sound the same. You can play with the end of hose to find the best listening points. If they don't sound the same then you need to separate the linkage between the carburetors and make the adjustments needed. This would be the starting point to tune with 2 carburetors that have idle mixture screws.
How did first motor run with that cam and lifters . I think you said that.
409Steve62
Active Member
I made a carb balancing tool with one of those edelbrock gauges to sync the carbs, did that first off… the first motor was only running off the rear carb only, when you tried to floor it it would shudder and gasp for air. The front carb was doing nothing and not engaging… so I just went to fit some headers and found the crack and tore it down . Was not good inside either.. been pretty tough getting to this point and still having issues but hey the saga will continue 
Was your cam degreed in . If so how was it set.
409Steve62
Active Member
Msd blast 2 coil. Unsure on the cam question but may have just been lineing up the arrows on sprockets
I would try another known good coil. My new MSD blaster coil failed and during the process of failing, backfired and blew up one of my blowers. Had another member have one fail, and I happened to have a spare on hand. After replacing the coil, he ran his fastest ever time. When a coil fails, there are endless symptoms. Nothing definite. Easy and cheap try.