Tuning Holley 600 for street ported 12a
 

Iam looking for info on tuning a Holley 600 for a street ported 12a.
The only starting point I have so far is to start off with 58 jets for the
primaries and 56 jets for the secondaries. I dont have it on my car
yet, but should be on shortly.

um, 600 is a little big for a 12a street port..

Are you planning on drag racing this? cause holleys suck on turns, unless you buy new float bowls.. (it is because how they are mounted on a rotary)


Can't offer a whole lot of help beyond that though sorry.


-Zach

I plan on having it on the street. I know about the center hung
float bowls already. Right now I have just installed the 600 on
my stock 12a. It is running pretty good for not tuning it yet.
All I have done so far is remove the choke and install 57 jets all
around. The speed shop didnt have the 56 and 58's. She easily
eats 2nd gens with out a problem.

Now, street ported, just brakeing it in. Runing like a champ. Got 57 jets in the primaries and 62 jets in the secondaries. Still need to get the center hung float bowls or notched float bowls with jet extensions? Not sure on which one works better. Any suggestions?

yeah... webber 48 ida... its easier to tune

Easy is not always better!

Run your two adjusting screws all the way in and then back them out 2 1/2 turns. Adjust them from there in 1/4 increments until you get your desired response.

Sounds like a plan, I will try that and see what happens.

what happened?
 

Hey there, Im also tuning on a 600 with streetport 12a.
Wondering what the outcome was.

Iam currently breaking in my engine, so I dont have any solid runs. Iam running 57 primary jets and 65 secondary. Everything else is basically the way it came from the factory. I removed the choke added a 1" spacer under the carb and have a screw to make my vac sec open slightly after primaries start to open. What is your set up?

Also, it seems that more people at the track use Holleys than people on the net? There is not much info here, but doesnt mean it will stay that way! There is more people here with Webbers than Holleys?

Breaking in mine too,
I started with 57 primaries but have rejetted to 62's
A # 7 metering plate, pluged off the power valve. #37 squirters and converted to a mechanical secondary system. Ive still got a little tuning to do but it runs well.

Iam not sure what #squirters I have installed. I had the same size jets as you run currently and ran good but felt like their should be more at the top of the rpm range, that is the reason I stepped up to the 65's, but doesnt seem much better, if it is it is slightly.

Is the #7 metering plate your 62 secondary jets? Are you using the plate instead of a metering block? I dont know too much about the Holley's Iam Learning as I go.

I am just learning also, yes the plate is in place of the block, I had the #7 plate is the reason its in there, I have read of these setups using the #8 plate I would like to get a "list" of what the plates are comparitively to jets. anyone???
What is this "screw" to help the vac secondaries open up? how do you have that working, Ive got a vac sec pod that Im just not using, Im still working on the mechanical linkages and there ok but not quite right. Getting the cams lobed right to go WOT is testing my patience.

When I bought my metering block it had a list of # plates and comparitive jet sizes, I will look to see if i still have it. If I do I will post it for you. Also the "screw" I talked about, is exactly that. A simple screw that makes the secondaries open. I will post a pic of the setup I have, maybe tomorrow. It is simple and alot of people dont like it?

Very cool, apprieciate that. lol alot of people here dont like a lot of things, whatever works, Ive built a wide body car so according to many on this board ive allready commited sacrilege. Been building this for near 6 months now. Almost ready to post some pics and watch the origianal minded folks go nuts. lol

Body kit sounds tight, I always like the idea of more rubber on the ground! I will like to see the pics, I would post one of mine but this peice of shit wont let me upload my pic!

I got the pics posted(screw trick and Holley plate# to jet size conversion)

http://www.tamparacing.com/gallery/s...=7&thecat=3018

http://www.tamparacing.com/gallery/s...=7&thecat=3018

I see, I made a new arm to open mine quicker, same Idea though. Thanks for the jet conversion chart no wonder im having troubles feeling like a lack of power, My motor is starving a # 7 plate = 53's lol Ill get the #8 in there asap.

Yeah, I was wondering about that jet size. I had thought you said you had a #7 in there. Do you have your secondaries opening up before your primaries are fully open?

Not saying this is right: The way mine is set up, is my primaries open about(guesstamation) 1/4 of they way, then my secondaries start to open. Not sure if it is a good set up, but seems to work for me. Just putting out the info on my set up.

Im also opening at about 1/4 after the primaries. Ive read anywhere between 1/4 to 1/3.

vac advance?
 

813, curiosity, what did you do with your vacume advance? lead and trailing? full vacume on both?

#8 update
 

By the way I had to order in the #8 metering plate and it wont be in until Friday. My car goes to the paint shop on Friday and will be gone for 10 days so looks like it will be awhile until I know if weve found the cure. *sigh my impatience is killing me.

My vac advance has NO vac! The trailing advance is completely advanced and screwed down to lock it in place(where the vac tubes hooks to on the distributor)

Currently Iam looking into Direct Fire Ignition. One of my igniters died and I have a friend that wants to get rid of a MSD 6a box and that will take my dead igniters place. Supposedly it is the only way to go when it comes to ignition on a rotary!

If the trailing is not advanced completely it will vary while driving? That is what I was told. I think the #8 plate will work alot better, I would lean out your primaries, atleast go back to the 57's? Run it first you never know?