Lapprentis--your Chevy sounds very close to my 383 Dodge truck. I suspect too rich a mixture. Or vacuum leaks? Might go a bit leaner on the rod/jet combo. Re; my method above to figure a single final number try one size bigger (thicker) metering rod. Read what I said carefully then it makes sense. More I think about it, I have tons of questions. To work well, the Groove is best applied to an engine in good condition, the older it is, the more questions I have. Since this is a straight Carburetor, that says it's 30 or more years old?
Is there any change in Driveability, is there any more torque off-idle than before the Groove?
What is Idle Quality like? Is this engine all stock? How many miles on it? Single or dual exhaust, manifolds or headers? Can you pull one spark plug and see how the color is?
Also consider adding a fuel press. regulator, get a reading of existing pressure first, then go down in half-lb steps till it stumbles then go back up one step.
Is this Edelbrock new or used? Ever been Rebuilt or at least cleaned out? how old is it?
How familiar w/ carbs are you, ever had this Edelbrock apart? (it matters)
Patient step-by-step measuring and checking is required here. do ONE change, observe, and so on. Put a vacuum guage to manifold vac, see what ya have first, along w/ fuelpress. check.
I assume your valves are properly adjusted on that Small block? And you are sure of no man. vac. leaks? Is dist. vac. advance OK? Brake booster? Oh and what intake manifold are ya using, is it a stock one that had a Q-Jet before? If so, what adaptor do you have under that Edelbrock? Many carb. adaptors out there suck, IMHO. Some adaptors could mess up what the Groove does...Also is the PCV system still stock?
And then there's Ignition, Just exactly what do you have? Condition of cap/rotor/wires? Resistance of plug wires in Ohms?
gotta ask all these questions w/old carb'ed engines.Sorry to bomb ya w/ questions but SO MANY Things could be off w/ an older ride! I know ya said you replaced gaskets on this Small block...but I've seen a LOT of stuff wrong on older engines! Not sayin' bad about yer' ride, Mate, just askin'... W/newer stuff it's safe to assume most factors are OK, older stuff, well...
My '68 383 could definitely stand more attentiom but it mostly sits. Is this truck a daily driver, how do you use it? If ya answer my questions, I can form a better idea of what you have here! BTW, pics of this engine w/ air cleaner off, in fact Several pics would be a good idea here. You could list Year, mileage, and the rest and I'll try to help you. Basically w/ old stuff I use Napoleonic Justice: guilty 'till innocent!!
And if any Chevy Small Block guys want to chime in on this that would be Great too!
It can be more tedious to dial in a carbed engine w/ the Groove than an injected one, YOU are the computer here!
Founder and Constant Aide to Gadgetman
Gadgetman Reno, NV
Pay attention! The Pressure Regulator is a key component with all edelbrocks. The company recommends 4 PSI and most systems put out a minimum of 7, so they over-pressurize the float bowl, forcing fuel through that is not necessary.