just no power over 3500 rpm.

[Grumpy]

Hi all.I am trying to set up my timing after my HEI died. I brought a MSD 8360 in view for future engine up-grades!I have a sbc 327 with my reconditioned 283 heads.YES i know not the best,as my 283 ate the crank and we got a deal on a 327 that we rebuilt minus the heads as they were too far gone.
At the moment i have 12 initial and a total of 32 degrees with vacuum plugged.My tachometer died so rpm by ear!I have tried many of the timing set ups and have narrowed it down to 2 settings of advance springs.Trouble is the car feels flat at higher rpm!Is this because the advance timing is coming in way late according to the MSD chart (over 3500rpm)... Yes i know ...the heads!!!Oh and the cam is a Comp Cams CL12-206-2 if that helps.
Many thanks,
Philip

https://www.jegs.com/i/COMP-Cams/249/CL12-206-2/10002/-1

a flat tappet hydraulic cam designed to produce power in the 1500 rpm-5200 rpm power band,
may not be ideal in a short stroke engine that can in theory easily spin 7000 plus rpm,
Id try verifying the ignition timing ,certainly, and ideally post pictures of your spark plugs as a good deal about the combustion and timing can be seen on clear color pictures of spark plugs
id verify TDC and the timing,
but the issue of no power over 3500 rpm may be throttle linkage,related,
(not fully opening)
carb jetting ,
float level,
fuel delivery
,tuning, or ignition timing advance curve, related, it
may be fuel delivery, or weak valve springs or a worn cam,
a restrictive intake or exhaust system,
or several other factors, all must be checked and verified.

read links
http://garage.grumpysperformance.com/index.php?threads/verifying-your-real-advance-curve.4683/

http://garage.grumpysperformance.com/index.php?threads/finding-top-dead-center.967/

http://garage.grumpysperformance.com/index.php?threads/is-backpressure-hurting-your-combo.495/

http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/

http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/

http://garage.grumpysperformance.com/index.php?threads/carb-tuning-info-and-links.109/

 

[chasracer]

You didn't say which 283 heads you had but I can tell you that back in the day a buddy had a '66 Nova that had a 327/275 motor in it. He put a Duntov 30-30 in it and ended up pulling some rocker studs. So he came across a set of 283 heads that were close to bone-stock. That car was an absolute screamer after that and took out more than it's share of 440 powered Mopars that were kings of the street when I grew up. We always figured that the compression ratio jumped up something fierce as the 283 stuff had a much smaller combustion chamber than the 327 head. So, if you can get decent fuel, I would get all the timing in by 2500 and see how that works out for you.

 

[Grumpy]

Well after head scratching and a little more thinking about what Grumpy had written,i stood back and thought more! Yes KISS...Keep It Simple Stupid!
I found that the kick down cable was moving around at times and jamming the throttle half closed!
Would not do it all the time! Still to find a tach that works and also to confirm fuel pressure!
Dropped initial timing down to 14 and have about 36-37 total.Goes like a rocket now!

Next Drag meet on the 8th!
Thank you Grumpy for your help!

Now back to playing with cold-ram air induction set ups!