thanks for the additional info michael. My Scout was bought by my father, brand new in 1977 at a IH dealer on the north side of denver. Wonder why the smog regulations want the timing set at 0? Does that insure all the gas is combusted? I am in the car business my self and all the cars we are selling have what they call a "high altitude chip". I bet it is the same kind of modifications you were speaking of in the post.
If there is any one out there that is looking to increase the power/throttle response of their IH motor, I really recommend the "power timing" described in michaels write up. For me the response gained was more then when I got my 4bbl carb, and electronic ignition.
The "power timing" can be done to any engine correct? I am going to pass this info along to my brother, he has an 85 Chevy..350...
Yes! However...back in the day, pooters and chips were just a figment of texas instruments and ibm's imagination (screw bill gates, he didn't "develop" shit). We did it by actually swapping hard parts and changing the "adjustable" specifications such as timing, removing carb limiter caps, adjusting carbs, and then re-installing limiter caps which were only available in the "kit" dedicated to each vehicle that went through the "pdi" process at the delivering dealership. I'm sure you know what pdi means!
The "0*" base timing spec was the same for many versions of IH motors that were true IH production items. The outsourced motors such as from rambler/American motors had their own unique set of specs/smog gear/service issues!
In fact...many engines of that era (depending upon base platform and many other factors) used a timing specs of "super-retard" such as 4* atdc!!! But those motors also had completely different camshafts profiles, cam timing specs, compression ratios, etc. Fortunately for us today...ihc did not get into all that stuff....an sv camshaft is an sv camshaft, the profiles never changed nor did the cam timing spec! Compression ratio/combustion chambers "shape" did change though. Another factor that all oem rigs had that was never incorporated into ihc stuff was engine thermostat setpoints of 200*f>205*f and beyond.
And keep in mind...back in those days, the emissions certification only delt with idle emissions, not a dyno run under load such as is done since the early 90's. So the manufacturer's only gave a shit about making the individual vehicle pass smog when it rolled into the "hot test" cell at the end of the production line for emissions certification. They didn't give a crap whether it would actually cruise down the road! Thus the dealership service departments were inundated with customer "drivability" complaints for years! That fact is why I always make these snide comments about the 1970's being the absolute low point in domestic vehicle technology/production...talk about a fiasco! And the "fixes" for this shit were flying out of the service engineering departments on an hourly basis!
Nowadays, for the most part, all ya gotta do is plug in the scan tool and "fix it". In the worst cases, we change "chips" or flash more, and actually download a dedicated fix for each vehicle in some regards. Exactly why I don't work on "modern" stuff, not even my own!
If yore bro's '85 has a carb and conventional hei delco ignition, then yes, powertiming will work. If it's efi or even and electronic feedback carb ( call those cripple efi), then it won't work 'cause the pooter controls timing. The hot tickee for an '85 chev 350 in anything is a "built early-style motor with carb and a real ignition system! But then...it won't smog for street use!
Don't even ask about powertiming a fuckin' prius or anything that's "green". Those aren't motor vehicles/cars/trucks...those are gummint-mandated transport devices that will never darken my parking lot!
