Single plane Manifold.

[blue69runner]

I have a Holley mid-rise on my 383 with half dome pistons. With the thumper cam. 9.8 to 1 compression. It is an open plane and not dual. So is there any suggestion. On if this could be some of my problems with motor running and driving. Read the Edelbrock forum on the dual plane and single plane. 650 Holley carburetor. 3/55 rear gears and an A833 transmission. Have the orange ECM box with Electronic Ignition. Going to change to the blue box next. Runs fine when cold and driving but when it gets hot like stop and go traffic it goes all over the place from missing to bucking spark knock. Could the intake have an effect on this.

 

[pnora]

I have a Holley mid-rise on my 383 with half dome pistons. With the thumper cam. 9.8 to 1 compression. It is an open plane and not dual. So is there any suggestion. On if this could be some of my problems with motor running and driving. Read the Edelbrock forum on the dual plane and single plane. 650 Holley carburetor. 3/55 rear gears and an A833 transmission. Have the orange ECM box with Electronic Ignition. Going to change to the blue box next. Runs fine when cold and driving but when it gets hot like stop and go traffic it goes all over the place from missing to bucking spark knock. Could the intake have an effect on this.

No. Sounds more like an ignition problem. Intake will vary on engine combinations as far as overall drive ability and performance but will not have the conditions you describe. Start with using a known good box. Any one will work. One other concern could be lack of fuel. What pump and what pressure are you seeing?

 

[gtxrt]

fuel might be getting to hot.

 

[Mick56]

If you have a heat riser, is it working ok? How hot does the engine get while running? When cold, the engine will run richer with the choke on. Maybe it's getting too lean when warm.

 

[1967coronet]

Coil and or choke adjustment.

 

[ruffcut]

Sounds fuel related to me. ruffcut

 

[blue69runner]

I can take all the suggestions and try what I have been doing. Weeding out each and all of the prescribed symptoms. Nothing like trying to chase down small things. Thanks for the info. Have a blue ECM box and going to put it to work. That is my thought the box I have now may be breaking down after things get hot. Will let you know what I find out. Blue.

 

[blue69runner]

No. Sounds more like an ignition problem. Intake will vary on engine combinations as far as overall drive ability and performance but will not have the conditions you describe. Start with using a known good box. Any one will work. One other concern could be lack of fuel. What pump and what pressure are you seeing?

Holley manual fuel pump. It is new the air right I had on the car went bad and set me up when driving home from out of town. Bummer. Do not remember but believe it is a 6-psi pump.

 

[Some Car Guy]

Make sure whatever ecu you are using has a good ground. I run a dedicated ground wire and never look back. The ground can get poor in a hot engine bay, but still be good enough when cold.

make sure you have a good carb spacer to block all the heat. If I find anything less that the 3/8 spacer under a carb that has to go. Todays fuel just won’t handle heat coming into the carb. An aluminum intake will transfer less heat directly to the carb, but if you watch for hot crank time when hot back to back between just a gasket and then a good spacer you’ll notice a big difference.

make sure you have a blocked heat riser valley pan

the single plane will be fine, I ran a street dominator on a 383 and it was fine. Guys get upset about those for some reason, but they are the ones that don’t know how to make do with what you have or can get cheap. If a local guy has a cheap intake that fits under your hood, should you buy it or spend more money to retrace down an intake somebody said did a few more ponies or ft lbs on a dyno? Either way, it’s not the source of your troubles.

 

[Some Car Guy]

My car had a hot running issue, I found this junk under the carb. I’ll tell you this won’t cut it. A 3/8 fiber spacer did the trick, without any mods to the stock choke stat on a 440. Ive had to do the same thing on past rides.

 

[WileERobby]

When diagnosing any condition, use my MEF method. Mechanical - Electrical - Fuel systems, in that order. For example: You can drip gas down the carb throat and the engine will run, but if the prior 2 systems aren't functioning correctly, it ain't doin' nuttin' !