Firebird1984

Ok guys, I need a little help. I have a new GM crate engine, 350 swapped into my 1984 Firebird. It starts up well and idles well. It has the ESP Edelbrock manifold with the Edelbrock 1406 carb.

I have put about 100 miles on the new engine so far and I pulled the plugs to check them. So far they are really clean looking, so I know I am not too rich on the carb. There is a very very slight tan/grey deposit on the white insulator but that is hard to even see. Since there is essentially no real deposits on the insulator, does that indicate I may be running a bit lean? If so, my guess is to go one step smaller on the rods for this carb to allow more fuel flow and richer mixture. Am I right on this or am I worrying about something that is fine as is with the way the plugs look? I'm not too sure how much of a deposit should be on the insulator after just 100 miles.

Thanks!
Brad

84z28350

the 1406 is a lean carb


like everyone else here your going to have to get a kit and go a bit fatter if you want to get max performance from that motor.

Firebird1984

Thanks for the reply. I appreciate it. I think I'll install the next smaller set of rods and see what happens. It does seem just a bit "underpowered" when I step on it a bit. I'm keeping the "stepping on it" on the light side as it's still breaking in. I just don't want to burn a valve or piston by going too lean. Again, thanks!
Brad

xpndbl3

iTrader: (5)

you need only to cruise the car for 10 miles really to pull a plug and see how they look. once you get the primaries dialed in then start tuning the secondaries.

Firebird1984

Well, I bought a calibration kit for my 1406 Edelbrock. I switched to the next smallest (1 step richer) rod for the primaries and went to the next step richer on the secondaries.

All I can say is WOW! What an incredible difference in how the engine responds! Very smooth and it seems like I just gained an extra 40 horsepower! No kidding... it made a HUGE difference in how it accelerates, cruises, etc. The power comes on smoothly now, not with a bit of a hesitation as before.

Thanks for the replies. You were right 84z28350, the 1406 is jetted very lean indeed. Next day off, I may just play with the rods and jets again and see where this leads me. Again, thanks for the replies and good info. I'll have to drive it just a bit further and pull the plugs and see what they show.
So far, I'm a happy camper!
Brad