do i have to much carb?

[360demonRT]

95 truck shortblock
906 stock vortecs
eddy RPM
750 vac, holley
lunati BMII (.480/292 109?)
1.5/8 lt's > about 4 ft. straight 2.5"
th350
unknown stall... footbrakes to 22/2300 before pushing through the brakes, pretty sure its not a lockup
4.11 gear
28" tire


right now the car is down due to a dead stock replacement fuel pump (sure it wasnt putting out enought anyway...). i had planned to pull the motor this winter to swap for an lsx... friday i found out that my floorpans are pretty much rusted out, and the rear frame rails (wich i knew about) are close behind. that being said i'm going to try to make this combo work for me as best i can while i save money for some rust repair #-o . anyone want to make some tweaks to my combo? lol, i plan on putting in a holley blue to take care of the pump issue. feel free to comment or criticize on things you would change if it was yours

 

[art]

Well the old formula still works so plug your numbers in and see:
VE X CID X max RPM / 3456 = CFM
VE being Volumetric Efficiency. Since you have free flowing intake,heads and exhaust use "1" for that value. If it was a plugged up stocker you would use .85 or something along those lines. Super or turbo charged engines you can use 1.15 or more.

So 1 X 350 X 6200 = 2170000 / 3456 = 627.9 CFM

So you may have a bit too much, but with vaccum secondaries you should be safe IMHO.

 

[LS6 Tommy]

Technically, you can't be oversized with a vac sec if it's not rediculously out of tune.

Tommy

 

[360demonRT]

after i get a pump i need to buy a pack of jets and let someone loose with it that really knows what the hell is going on... not me lol. hopefully after my wedding i'll be able to get to the track and see what it turns... if it runs mid/low 9's i'll probably be overjoyed

 

[360demonRT]

so when it comes down to wanting to run the number... i'd probably be better off trying to swap around and get a 650dp or something along those lines? i read that vortec heads are done by 52/5300 (think thats what i saw) so that may be the better choice...

 

[art]

That double pumper may not be the ticket. Try jetting/powervalving your 750 first. I think you will be pleased with the results.

 

[360demonRT]

i came from the world of EFI mustangs lol, it'll take me a while to get the hang of carb tuning. what would you recomend as a good front/rear jetting as a starting point? i know there's a way to check if your rich or lean from plug reading, just dont know how to do it.

 

[barnym17]

IMO the best way to tune jetting is mph at the traps. Set the jets at the stock setting (this will be on the rich side most likely).Make a run then go 2 sizes bigger make another run if mph is higher keep going richer till it slows back up 1 step and you got it.If mph does not improve at first go 2 numbers leaner use the same process the best jetting is the one that gives the highest mph.Same process for the secondaries.

 

[Anonymous]

The secondarys in the 3310 are metered with a plate that is non adjustable. After you get your primarys set with the method above then tune the secondarys with the spring in the vacuum canister looking at the trap speeds like before. You can also take out the metering plate and put in a secondary metering block and jets if you want. This will give you some more tuning on that side.

 

[360demonRT]

so buy a jet kit... a set of reusable bowl gaskets, and go from there? hopefully soon i'll get this thing lined out #-o planning on buying a holley blue pump. what's the recomended psi for a combo like this?