Magnum 300 crate engine - how should it go when tuned up right?

67Dart273 said
Well I suspected. And it's slower than a 318 2bbl? That has to take some WORK

Mufflers.......not a chance, unless they were for a Pinto. You obviously have duals, and there might be "a little more" there but nothing like you are looking for

Distributor........You know the ignition curve? That is where you START. I've seen "everything" in my 70 years including RUSTED ADVANCE mechanisms which were just plain LOCKED

WHERE is the timing initially and HOW FAR does it advance? I DO NOT EVER play with an unknown engine WITHOUT using a positive piston stop to verify TDC and then grabbing the timing light.

Carb........You say you "need a rebuild." Does it leak? Won't idle? Why? "Needs to be leaner?" Why? At what RPM? Idle/ mid/ power? You have to figure out how to nail this down.

FRANKLY IN THIS DAY AND AGE I don't know how anyone can justify buying an expensive engine and NOT springing for a wideband O2 setup. They just make things SO much easier

..........And then there's the "stupid simple" stuff.........have you checked that the carb is actually fully opening with the throttle?

Good points all around.

Carb doesn't leak but the advice that I keep hearing is that ethanol content in our gasoline eats gaskets, etc. Just a hunch that a flake of gasket could wander its way into a jet or something.

Good call about making sure the throttle fully opened...and it does.

I suspect that it could be leaner just based on the smell of the exhaust which seems to be laden with some unburnt gasoline. It also bogs a bit when I tip into the throttle which could be explained by it running too rich. Is that scientific? Not at all. That's why I'm here asking :D The plugs aren't obviously blackened but then again, I probably don't have enough miles to rely on that age-old method for fuel mixture clues.

The mufflers were low on my list until I saw the Engine Masters episode on YouTube (which seems to have been pulled). IIRC, there was a pretty sizable difference from stock type mufflers to some of the better performance pieces.

Yeah, my tuning experience has been with wideband O2/OBD2 access. It's a whole different thing to tweak fuel maps on your lap top. What setup do you recommend for these cars?

Thanks for all of the advice!!