Hey, is anyone out here running a Tunnel Ram on 454-502 Cube motor. Holley 600's or 750s, double pumpers or vacum sec?. I just picked up this metering plate converson kit from jegs that allows you to run the metering plate, but with jets like a metering block.
I dont know how far down i should jet the primaries, as a starting point with the new metering plates and what to start with on the secondaries? As for now I have 82's on the primaries and the stock metering plate in the back with my 2 600 cfm. The plugs burn pretty good, the usual dark brown, crusing on the street.
My motor is pretty fresh, i havent got into any serious rpm yet to burn any serious fuel..

Engine details are: AFR heads, UD 292/302 685/680 "454" 12.CR.

Thanks for any input from you guys.
I will have to post my setup running and photos as soon as i can get some one to host them. Thanks again.

WOW 82's on the primarys, I think most 600s came stock with 66s but I may be wrong. Are you running power valves?

Yes, i am running some 6.5" power valves. The cam pulls around 9"-10" of vacum @ around 1100 rpm idle. I have a 4 speed so i really don't have any idle problems. Thanks for the input for a starting point on the jetting. I do know my new setup is really buring some gas for crusing. I was getting around 9 mpg with my old set up and it seems to be like 3-4 mpg now. :confused:

well this should give ya an idea..........

most of the holley 600 carbs run 66 jets some a few higher and few lower......but the common design 600 runs 66 jets.

now since you are putting in jets in the rear most folks know with out a power valve you will go 8-10 jets over the primary.

and just to back that therory up .....a standard holley double pumper 600 cfm will run a 66 jet primary and a 76 secondary.....

now with your combo.......i think it would be to your benifit to start at the bottom and work up

it looks like the 82 jets was making up for the lack of the secondary's metering plate.......specially if its still stock and has not been drilled.

knowing what you got i would start with 70 primary's and 80 secondarys and start your tunning from there.

watch the plugs and not get on it hard till you have the jets pretty close.

by the way a 850 holley carb runs 80 jets box stock...............

We ran 6109s (750s for tunnel rams) the jets stayed pretty close to stock. 75 front with power valve and 76s rear with no power valve. the pri. jetting needs to be richer than a normal single 4bbl because of the poor signal to the carb at anything but wot and high rpm. I don't think you need anything close 80+. Keep coming down until your part throttle gets weak.

Thanks Guys. Will do. I will keep ya posted on the out come.
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