View Full Version : New heads and intake, Carb Jetting

04-27-2007, 10:21 PM
has anyone had to rejet their carb. I just put new RHS heads, Performer intake and roller rockers on my '92 351 HO. I have reset the idle mixture but want to check the jetting. I believe it is run it at steady state. Shut down. Pull plugs and check for color. White means lean black means rich. Want to be tan or light brown. Anyone have any tips.

Hoosier Bob
04-27-2007, 10:50 PM
Used to be run it full, shut her down and then pull the plugs and check. At least in motorcycles anyway!:o

04-27-2007, 10:55 PM
yea that was what I was thinking. I am planning on running at 30 and then at 38 to check the jetting when the secondaries are open. I would hate to lean this out and ruin a new set of valves.

Hoosier Bob
04-27-2007, 11:17 PM
Bump the thread every once in awhile when more members are on. I am sure someone has done something like this and has the set up. You may want to tell them which carb unless 93' was the only year with the infamous 4010.

04-30-2007, 09:37 AM
You'll want to check the primaries first (secondaries disconnected). Run WOT for 30 seconds and shut down. Unless you have a good scope, the easiest way to read the soot ring is by chopping the plugs. Take a look at a few on the rear as well as the front of the motor. A soot ring of 2.5mm and under is too lean.

Once you dial in the primaries, reconnect the secondaries and do it all again.