This is a long post - but there's abit to think about before swapping out the heads or cam -
These things need to be checked in stages - simplest first - atm we're all assuming heads or cam......
Im not disagreeing with Bobby or others - the heads would be hurting velocity - and as Bobby says, there may be some shrouding going on..he's the expert there......(and I am wondering about your comp - but we need specs)
.....but.......
A. - Check your plug leads! (some confuse a lumpy idle with a missing pot),
B. - MOST IMPORTANT - are you getting full secondaries at WOT? (Get someone to stand on the pedal and check the secs. with a torch- open the air door with a screw driver and look down the throats) ,
C. - COMPRESSION CHECK - Dont assume the rings have sealed - Check your static compression with a comp gauge - should have around 180 - 190psi for 10.5:1
Facts for you to consider -
1. - Your stall will be putting you close to the cams power band....(My 282S solid comes in around 2700 so yours should get lively even a little earlier) - so cam timing should not be an issue if installed correctly.
So the cam is not "too big"
2. - Tyre height has an effect on gearing - 3.5s is not real steep, I agree, but:
It takes very little torque to "flash" the converter , its what happens when it locks up that is important - ATM your converter should be allowing the engine to rev close to the cams power band - (its a 2800 TCI for chrissakes)
- it sounds like when the converter locks - theres no torque there - so theres a power drop off somewhere.
This is why we are suggesting heads, A/F and cam timing - the engine can rev OK, but its not producing the goods when under load. Make sme think its more than ONE thing......
3. - Your ignition timing at 21 static is almost identical to mine..its plenty to get the car to hurry up from "off idle"....again assuming the cam is "in sync" with the ignition timing.
For all these reasons..I suspect more than just heads......I reckon you've been pitched a "foul ball"...
ITs either:
A mechanical "set up" issue (see above)
OR
The combo (heads, cam timing, tyre height etc)
I just cant see your heads (as they are pretty "mild") affecting your launch that badly at 2700 rpm.....not unless they've had the heck hogged out of them......
However Id agree with Bobby - they're not ideal -
If the maintencance issues check out - then look at the other members suggestions -
1. - I agree- Swap the heads for the 302s and get BJR to pocket port them - your cam is pretty mild really.....
2. - I BETCHA your shop installed the cam "straight up"...get it degreed...
3. - I agree - hit the Dyno or BETTER STILL - dont pound the engine, get someone with a $300 A/F mixture meter and test it under driving conditions. Any good "tuner" shop should have one....
4. - Be aware - ypur ig. timing is NOT the problem - BUT - Get your dissy curved to be 34 all in MAX - Cylinder head temperature escalates dramatically with higher all in timing at high revolutions - it does your engine no favours. (Not to be confused with Vac advance that advances the timing at cruise revs)
Lastly -
Id like to know how tall your tyres are also - then I can run a comparison with mine - which is a VERY similar build re cam, carb, intake and heads) , and only 20 cubes more.
Also, what was the piston installed deck height? (above or below), and the piston part # , if you have this figure we can calculate the actual static comp.
I dont wish to sound bitchy - but you shouldnt ignore the possibility of a sloppy assembly(cam timing, comp calculations, valve seat sealing, poor ring seal)
Im guessing Bobby cant say this - due to "professional courtesies" , but its what springs to mind if the basic checks are OK.............