No way.

listen to your engine builder

Most people run 34-36 with a set up like yours. It's best to use a piston stop to find TDC. On engines with a lot of use, the ring on the dampener can move. Iron Eagles do flow well and should make more hp. I would go back to that Dart intake as well.

Did you ever bump the timing up????

I agree, go back to the Dart intake. The Edlebrock may make better torque down low, but will loose to the Dart in the upper rpms.

ck make sure that throttle opens all the way...you never know..Rob

Another thing to keep in mind, given your cam and components, your engine probably makes it's peak hp in the 5600-6000 rpm range. Re-propping or re-gearing seems like a good idea.

Fixx
 

you have too much cam for your engine,,changing intakes is not going to help at all!!!!! you will still be at the same rpm in the big end.. before you change anyting try putting the old carbs back on..you went from 800 cfm carbs to 750 cfm when you did all the up grades..bump the timing and try the old carbs first..

check your spark plug's after a hard run,,i bet their white...what jets are you using in the carbs?? in the 800 cfm carbs i think the stock jets were 72-84?..you put in a bigger cam and better flowing heads,, the engine will need more fuel which i think you may be lacking. my guesstimate would be a 850 cfm carberator would put you @ 5200 rpms and which is the max rpm for that engine..

I always kept the 750 Carbs never went to 800 or 850.

Fixx
 

is the list # on the choke horn 9022? did you jet up?

I agree. With that cam, I would prop for 5500 RPM. I would prob try 34 degrees total timings, or maybe 36. Of course make sure you are jetted properly. 420 mercs should have the 800CFM holleys if they are the original carbs. I believe stock they were 81's in the primary, 91's in the secondary, 6.5 power valve in the primary side. With your heads and cam, and turning 5500+rpm, you may want more jetting than a stock 420 merc. Of course the air bleed size comes into play too. Plug readings can be tricky with todays fuel.

PS, I'd go back to the dart intake. But it wont give you 1000 RPM. However, bolting on a supercharger might!