I agree with Milt's comments about quench and the cam design being
bigger factors.
No offense to the ROP guys, but I really doubt that the thought or
execution was very thourough, especially the guy with pinging problems
on 93 octane pump gas. For example,at one point he mentions running it
with the stock 307 intake. His car is an '85 which would have had the
swirl port head 307 with the matching A5 intake with tiny ports. The
ports in this intake do not match up worth a damn to anything but a
swirl port head 307 (or maybe a 260). I also wonder how much of the CCC
system is hooked up and functioning on his car.
The ECM calibrations for the 307 are set up with a lot of timing advance
and it employs a LOT of EGR flow to keep pinging down. The ECM engine
on the later swirl port 307 also expects a strong engine vacuum signal
unless the car is running near WOT. Even with the stock 307 in place,
these cars work a lot better with the pretty much the whole engineered
CCC system in place. (You can get rid of the A.I.R. without causing any
driveability problems.) You also need to make sure the EGR valve is
properly sized for the engine you install. The factory 307 valve does
not flow enough to work well on a 350 or 403. For your application, The
VIN 9 ECM calibrations should be closest in stock form. After that I'd
probably try a '88-'90 ECM from a B wagon or RWD Cadillac. These
incorporated a knock sensor which does help to reduce part throttle
pinging quite a bit. You may welll be OK with the stock '86 ECM if
everything is working properly and you have the EGR sorted out.
All of this has been done successfully. It does take time, care and
thought. If you just cobble together an engine without really thinking
it through and then drop it in a car with a CCC system that is not
really working properly to begin with, you are bound to have problems.
Regards,
Fred
