I like to think I can tune my own engine, but I would like to see what you're methods are. Typical sbc just under 10 to 1 Iron heads, Holley carb, petronix cast look dizzy. Crane Hydraulic cam with lash set to spec. My method is total timing set to 35 at full advance with vac advance plugged. Set carb idle screws with vacuum Guage for highest reading. Is that it? Any other tips and tricks? Let's see what we can learn
The obvious, make sure motor is up to running temp. For me, when setting the timing I simply plug the advance, bring the rpm's up to 3000, and advance the distributor until the engine just starts running rough, then back it off slowly until it smooths out. I also set the needle valves with the engine at idle, in gear,with either the parking brake on or have someone pushing the brake. Now get ready for a WHOLE bunch of ideas....
I guess you miss out on all the fun of filing the points, measuring resistance, checking dwell angle, etc. Awww..... Sounds like you have it pretty well under control. Might also check the float levels, and look at fuel filter, etc.
When I did this for a living back in the 70's a tune up included: removing the plugs and doing a compression test, removing the distributor cap and wires and checking resistance on each wire, replacing the plugs, servicing the advance weights in the distributor, replacing points and condenser, inspecting the air filter and PCV system, servicing the battery, and final tune up using and ignition analyzer which had advance timing light, vacuum gauge, dwell meter and scope. It wasn't a cheap tune up, but it really was worth the money. The first step was always a compression test so that you didn't sell a customer all the parts and then tell him he needed a valve job.
Advance curve is another opportunity. What's your initial timing and what rpm is the advance all in. DIstributor curve kit and springs is less than $20 and provides hours of entertainment and a good reason to go slam thru the gears and test your changes
Play with the springs in the secondaries (If a Holley) to maybe bring 'em in a little quicker...... Edelbrock shave off a little weight off the secondary air door counter weight. Need to take the top off to do that. Always tune on the meter rods and springs on the Eddy carb too. I like to stick on a timing tape on the harmonic balancer so when you play with the advance springs in the distrib you can SEE what the engines doing. 6sally6
“DIstributor curve kit and springs is less than $20 and provides hours of entertainment” Especially when the little screw either falls inside the distributor or worse yet when it falls outside the distributor. Hours of fun indeed!
How heavy is the vehicle ? The black spring is the heaviest spring. I never use that spring unless its in a 1 ton dually or something similar. Is the secondary check ball still in place?
36 convert 2700 maybe I never had the secondary of to check the ball. It has the quick change cover. And yes I tried all springs.
I use the "lean roll" method of adjusting the idle mixture screws to find highest rpm at idle, then turning the screw In to achieve ~ 20 rpm drop in idle speed. That's how I was taught many years ago, and IME it helps provide a smooth idle & a crisp throttle response. I actually spend quite a bit of time going back and forth between the 2 sides of the carburetor, because once you've adjusted one side it may affect the other. And I like to reset the idle speed inbetween adjustments as well. Taking the time to get this right makes a big difference in how smooth the engine idles and that transition from idle to acceleration. I can remember watching my dad do this, just using his ears. He'd also hold his hand on the fender with index finger extended and watch how his finger vibrated, a visual aid to how smooth the engine was idling. I'm not that good, I use a tuning tach and a vacuum gauge when I do it.
2700 is pretty quick, its usually not that like that on stock ot random distributors, if you're not getting pre- detonation youre probably good there. Depends if you want to try slowing it down and check part throttle performance. Thus is a good write up, and quicker than me typing it all out. https://www.badasscars.com/index.cf...duct_id=76/category_id=64/mode=prod/prd76.htm If youre happy with timing curve, secondary tuning on the holley can improve driveability, depends on your cruise rpm, if you're in primary circuit at cruise rpm, if you're getting any bog with secondaries at part of full throttle. You want to be able to cruise on idle circuit, have the secondary come in without bogging the engine at part and full throttle. Secondary spring swap article https://www.google.com/amp/s/www.mo...custom-tune-holley-vacuum-secondary-carb/amp/ Adjustable vacuum canister is another tuning tool for part throttle and overall tuning. I've never used one personally, most of my stuff has had radical cams or been close to stock. A lot of these changes are based on what the car is doing, combo of cam, vacuum, converter, gear, weight, cruise rpm. Make a minor change and drive a few times.
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