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View Full Version : Jetting holley carb on Olds 455 Pac-A-Jet



SeaSlut
06-10-2001, 08:56 AM
I have a 72 Beachcomber, 19' V-hull runabout powered by an Olds 455, Edelbrock performer package; stock point and vacuum advance distributor set 10 btdc@ 1100 rpm. Runs good.
I run exclusively at Topaz Lake, Ca (5000'ASL).
Carb is a vacuum secondary, dual feed, 750 with choke horn milled off and replacable seconday jets and springs.
My can any of you with a similar carb tell me what size jets your running?
I'm down to 73 and 74 and don't believe the old girl is living up to her full potential. I have gone two steps up and two steps down with little differance.
I think my fuel consumption is excessive but I don't want to go too lean.
Reading the plugs has been futile. Bosch platinums are clean: center electrode and ground electrode look new after 4 hours of hard skiing EXCEPT for a little black around the base that the ground electrode is welded to.
JET DRIVES RULE!
rog

tahiti jet
06-10-2001, 09:29 AM
i have a 18 tahiti with a mild built 455,
with a 850 double pumper and it runs great
i think you might try a bigger carb. but thats just my opinion.
ive tryed the same carb,and had better performance with what i have now

SeaSlut
06-10-2001, 11:04 AM
Was size jets in the pri and sec?
What elevation do you normally run?

montrone
06-11-2001, 02:23 PM
i have a 750 cfm edlebrock and the prim are 113 and sec. 110.
i herd the best set up is the torker II (2500-6500) rpm and the 750 edlebrock.
this is just my $.02 cents.

Nivels
06-11-2001, 03:57 PM
SeaSlut
Its the Elevation that you are running in. Call Edelbrock and they will tell you what jet size to use, and timing

timitunnel
06-11-2001, 08:42 PM
I don't think all your tuning should be concentrated on the carb. Check total advance of timming. If your on a tight budget you might consider go to a salvage yard and get an HEI unit out of a car.other wise consider a good after market distributor. Unless your motor is really built I don't think your motor will pull more than 750cfm at altitude so look at other area's for performance.hope this is of some help
Tim I

SeaSlut
06-15-2001, 04:56 AM
Okay then, Today I will measure out 32 degrees advance on my balancer, mark it, turn rock-it-boy (13 year old son, digs this shit)loose on the helm with orders to go straight at 3000rpm. I will then return to jetting and tuning ops on the carb. set it and leave it alone till October.
p.s. Looking for good used 455 block for a second motor.