the right carb?

[jer67stang]

im sure you guys have gone over a million times but im trying to get my car running at its best so any help=THANKS!

ok heres the problem, got a 650cfm double pumper w/stock jets had it for years=old carb, i had a problem with the carb making whistle under slow speed, but the went a way=(not sure how or why if it got worse, or what) i thought for years my 289 was over carb'ed but i just put a 331 scat stroker kit w/flat top, with some world sr heads, rpm air gap intake and a 512/512 292 the car idles around 7hg in park and around 5hg in drive, seems low to me, cause the 289 used to be around 10hg if i remember. also keeps spitting out the carb if you give to much pedal before its under 190temp, the car seems that it got more stumble under 2k then flattens out about 5600rpm sounds crazy but no moving that much at that rpm. i tried a 670 street avenger with the 289 before i sold it case it didnt semm to have power in the upper end(wish i still had it to try now) but im looking at buying a carb, my cuz says to put a 750cfm on there but i think it might make it stumble more.

any help?

been looking at the new holley 0-76750BK

 

[D.Hearne]

The whistle ? Throttle shaft's worn in the base plate. The stumble's probably the timing retarded too much. I'd get another 670 if replacing the 650DP. I run a 3x2 setup on my 331. Three 250's.

 

[jer67stang]

That could be a problem I have a full mad with a light spring and heavy, and the timing is at 10 think that's too low?

 

[jer67stang]

Ops ^*full MSD

 

[2+2GT]

That could be a problem I have a full mad with a light spring and heavy, and the timing is at 10 think that's too low?

You need to get the the distributor done. Right springs or wrong, there's no way to know if the curve is right.

 

[brianj5600]

Ten degrees is definately too low. What is your total advance? Does it have vacuum advance? Did the distributor come with bushings for limiting mechanical advance?

More initial will help vacuum at idle and throttle response. I think 16-20 degrees initial and 34 total would be a good starting point.

The vent baffles have been known to whistle. Some people even call them whistle tubes.

 

[brianj5600]

After looking at MSD instruction, I would use the black bushing and choice C on the spring chart, heavy silver and light silver. Initial set at 17*.

 

[jer67stang]

Cool I'll give it a try and see how it runs keep you guys updated, thanks!

 

[jer67stang]

went to change the bushing to the black one and notice that the bushing weight pad was broken so got to wait for parts now

 

[69Rcode_Mach1]

Is your cam at at 292/292 duration and .512/.512 lift? If so I wouldn't expect too much more vacuum out of that thing. I am getting around 6-7 in/Hg with my setup right now at idle.

 

[jer67stang]

Yep same cam ok I bumped up the timing @16 right now, vacuum is about 6-9