Was a 750 over carbing?  Is the top end Performer or Performer RPM?  If its Performer (done by 5,500) then I agree.  If its Performer RPM (1,500-6.500 RPM) then I don't know that I agree with their assessment.  What kind of RPM are you running?

Holleys from my experience tend to act smaller than they really are.  We used to put 390 cfm Holleys on Jeeps with 258 straight sizes.  390 cfm should be almost enough fuel for a small V8 like a 289, yet that carb on a 289 would be a dog and it would need a 600.

There are ways to make a carb that's too big run decent, and ways to make a carb that's too small run decent, though you're going to be limited power wise because it will only flow so much air.  Do you still have the 750?

I do not still have the 750 . I sold it to offset the $1200 bill I got from the tech.
I did my math really well from cam to heads to intake. The RPM/Power Bands are all relative.

My intake is a Edel Performer. Heads are are RPM (I Believe)

The heads should have a part number stamped into the ends.  You can use that to figure out what they are.  If the heads are Performer RPM and the manifold is a Performer that's a mismatch.  You're strangling the heads with that intake. 

Cam specs?  What's the compression?  What's the exhaust?  What changes were made recently other than the carb?

Rpm manifold has a little larger runners/ports. Flows more and pulls to a higher RPM. Still behaves at lower RPM like the performer.
Tell'in ya fellas.....the "secret" is in  the timing!! Modify the advance curve and you'll think you jumped in the worng car when you "nail-it"!
6sal6

Ok....I checked my equipment.  Performer Intake Mated to Performer Heads....Im very pleased with the performance....
what im not pleased with is the Noticeable power loss from the 750 Carb to the 650!  unfortunately it is done and I am not going to lose again by swapping out the brand new 650 which cost me A LOT for another 750.....

My Jets as of now (thinking to compensate for the swapped 750) was to add larger Jets...72 primaries and 76 secondaries........

I am solely looking for the answer to "is there a general set standard for Jet Sizing" in the sense "primaries are always larger than secondaries" (kind of like if/when packaged for sale, we assemble with ie.68primaries and 72 secondaries).......

once I know if there is a general rule/understanding, I can play with the numbers myself......the reason for this is Ive noticed a much more potent exhaust smell since Ive switched to 72/76 configuration with modest power improvement...

lastly I check spark plugs and they have a "Light White coating on them"

many thanks
jeff

If the exhaust smells rich; it is.  That indicates the jets are too big.  You have to be careful with plug reading for two reasons.  One, if you have a high energy ignition of any kind (basically anything much more than points with a stock coil) reading plugs becomes essentially impossible.

Two, unless you shut the engine off at WOT, and then read the plugs; the results are unreliable. 

All that being said, carb performance is more than just WOT, and there's more too it than just swapping jets, though that's where you should start. 

Oh, and 6Sally6 is SPOT ON about timing.  When I got my advance in by 3,000 RPM and got the base timing set right you'd swear the car had 50 more HP. 

Thanks Sally and TKO.....

Ive been playing with my timing also.....between old mechanic friends and Youtube ive seen and read different things....

what do you guys feel is a good advance starting point with a 351W, Edel Performer heads, Mild Lift/Duration cam and MSD ignition (also bored 40 over if that matters....)

Jeff

(if you get a chance, give this a read http://www.superchevy.com/how-to/148-0403-seven-holley-carbs-test/)

Heads have a lot to do with how much total advance the engine wants.
The more efficient the head (AFR....Twist Flow etc.)  require less total advance.
The reason we need to advance the timing at all is because the spark needs to be in the chamber when the fuel vapor is compressed....so it can explode and cause power at the perfect time.....(real primitive explanation!!) Heads that flow real well have the fuel mix THERE a lot sooner than older/stock heads.
Mine seems to like 36* total advance @ 2000 or so RPM's.
The initial advance.....like 8*-10*-14* is irrelevant when you tune it for TOTAL advance.(36*)
BUTT..........there is 24* advance built into the Duraspark  distrib.   Soo 12* initial + the 24* built in =36* total!
The trick is.........getting the distrib to advance QUICK enough to achieve 36* total in a short 2000RPM range.
The stock springs inside the distrib are soooo stiff you would need to "rev it to the moon" and run 174mph to get it to FINALLY advance to 36 degrees!!!!
That s'why you need to install lighter springs!!!! The stocker sprangs can be stretched open with a screw driver with a fair amount of effort. The light springs can be "flipped" open with a "flick-of-the-fanger"!
Soooo go inside the distrib and install the light springs and you're home-free...right?!!....WORNG!!!!!!
You need to install a timing tape on the dampener/balancer wheel to SEE what your advance numbers are!!(Using a timing light, of course!)
Engine warm and idling.....bring up RPM's to 2000 and observe where the timing mark is in relation to timing tape. Twist distrib until the mark and 36* are aligned. You now have 36* total timing @ 2000RPM!!
Re-adjust carb and wiiing the engine a few times. It WILL rev quicker and be MORE crisp!
NOT DUN!!!!!!!!!!!
Check to see if you are going PAST 36* when you go higher than 2000RPM's!      38-42* will "prolly" be OK butt.....more than that could be "damaging". If that's the case you need to LIMIT the total advance to 36-38-40*!(This ain't brang surgery!)
You can bend the little tabs inside the distrib OR do like me and make a bushing to fit over the little post inside the distrib to STOP it from advancing.
Sounds complicated butt-it-snot!
WELLLLLLL worth the effort in performance. Total cost????.......under 20 bux!!
6sal6
PS.........Google it........there's pics and more  s'plain'in.

Are you running vacuum advance as well?  If so, my guess is that the issue is not your base timing plus mechanical advance, but that the vacuum advance is adding too much additional advance.  Most Ford vacuum advance canisters are adjustable via a small Allen screw through the nipple opening.  I've yet to see an engine that wouldn't take 30 degrees of advance.  Are you sure TDC as read on the balancer is really TDC? 

Yes, that is correct.  You can't really measure vacuum advance while the engine is static (i.e. sitting parked reving doesn't count).  Tuning it can only be done by trial and error while driving the car.  So, when you set total mechanical advance you are only taking into account base timing plus mechanical advance, which is the same under all operating conditions. 

HudginJ3 wrote:

No I haven't fiddled with my advance yet. I'm still trying to get me some edumacation on the subject. It seems to me that it is advancing to quickly and that 30 some odd degrees advaced is too much. I set the timing as per TKO's advice and drove it up hill as suggested. Now when it starts to ping maybe two or knocks or rattles or pings it downshifts. And the ping goes away. Driving on the flat just fast enough so it won't down shift is the speed that it pings continually. So I have backed off the timing till I learn what to do about the advance. So far I've learned that because of my heads and intake maybe 30 some odd degrees total advance might be too much. The other thing I'm wondering about is if I have leaned out the carb too much. I didn't realize that you can't use the plugs any more for a gage. My tail pipes are as black as the ace of spades but am thinking that might be oil do to the intake gasket issue.

Try it with the vac advance plugged and see if the pinging gets better
You are using hi-test fuel...right?!
6s6
 

Been messing with the vac advance for the last couple of days. I had forgot about the vac adjustment inside the canister. I turned it out about 4 turns (counterclockwise) and it doesn't ping as much as it did. Most notably when accelerating fairly hard from a stop it quits pining rather quickly as the rpm increases. I think now I have a place to start curving the dist advance if my thinking is right.