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Who's running a Holley with no choke horn?

14K views 27 replies 19 participants last post by  Tommy 
#1 ·
When temps are below say 50, do you have issues with keeping it running till it warms up?
 
#4 ·
Yup. Have to babysit it for a good 3-5 min. I have a 750 double pumper that I switched over to a Proform center section and it got a little better. My friend has a 650 Demon with no choke on his 69 camaro and he can turn the key and walk away on cold mornings. Makes me mad
Hi ya Slick!:rolleyes:.... Lugnut79 is spot on........common problem with chokeless carbs in cold weather warm up...

other factors in factory carbed engines in cold weather warm up that are lacking in the Hotrods of today are..

blocked or no heat cross over in the intake, heat stove off the exhaust manifold(thermactor), high idle step(choke related), or solenoid...
 
#8 ·
And when it comes to Pro Form!

If you have a 750/850 Double Pumper your better choice is the Holley center section and the same money. Same part used on HP series Holley

Holley # 134-300S or C

IMO
AL
 
#14 ·
I am running 750 DPumper with a performer intake here in Montana and in the spring it can be chilly in the morn. I sit and idle up so I can back it out of the driveway and then idle it down the road till it will idle on its own. dosen't needmuch persuation but it is the nature of the BEAST:yes:
I guess if you don't like it you could go with an electric choke.
 
#15 ·
I had a Holley 650 dp with the choke horn but no choke and had no problems when cold.
I just went to a Holley 750HP (no horn) vacuum secondaries and it takes a while before I can back it out of the drive even. My 650 was jetted rich maybe thats the difference.
 
#16 ·
On my Firebird I ran a 750 Holley that I litterally cut the choke tower off of. It turned out that with my drop based air cleaner, the lid was getting to close to the top of the choke tower and choking the engine when I put it on, so I got out the hack saw, pulled the carb, and cut it off at the track. I don't recommend doing it this way, but I did it in a pinch. I had to use this car for about 6 months as my daily driver in teh winter (ET Street's and all). With 11.5 compression, a huge cam, and 412 cubes, I'd fire it (it always started right away with 3 pumps of the gas), would hold the throttle at 2000rpm for a minute, then it was fine. It probably helped that it idled at 1200rpm. Now when I put this carb on my mom's 350, it takes like 3-4 minutes of feathering the throttle to get it to idle, but that engine idles at 850rpm. I guess it's just the nature of the engine.

As a side note, I've used a few Proform main bodies with very good results. Had nothing but issues with Demon's.
 
#17 ·
funny thing about this. Got me thinking. On my stock 350 engine with 268 cam and performer and 750 vac sec it would idle cold. When I put the same carb on my LT-1 it idled but wanted to die till it got alittle temp. Same carb on my junk 350 would have warm it up in the morning for about 3-5 mins.
But my 406 with compression and roller cam and single plane intake with an 850 it would idle cold. Hell even my dual 660's on my tunnel ram on my 406 idled cold. I just redid a carb for a guy with a 400 and with a 750 proform body and it won't idle till it gets some temp. I don't know...I know engines need more fuel when cold, ergo the choke to cut off the air supply. Some chokeless carbs I've seen idle cold and some don't Maybe it has to do with the manifold crossover and having iron heads vs alum?

I say if ya can't hold your throttle at 15-1800 for 5 mins then get a choke. Your engine will like you better when its warmed up.
 
#18 ·
I would be willing to bet that any engine that idles fine at 800 or so cold (with no choke horn), that carb is running rich. Side note, I'm running a proform base on my 650 and if I ever thought about changing the main body, I would try a proform.


Now a question, other then getting a main body with no choke horn, whats the reason to switching from the Holley main body to the proform?
 
#20 ·
#27 ·
Anyone who is contemplating cutting off their choke horn please restamp the carb list number somewhere else. Once you lose that number it can be very hard to find out what you have. There are many variations with the same bore size but different calibrations.
 
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