Holley 650 CFM question

I have a nice NOS Holley 650 double pumper I'd like to use on a 347 stroker. The inlet manifold is a duel plane low-rise Weiand.

Question: I'd like to orient the Holley for a forward pull cable (mid-mount engine) rather than rearward pull (forward engine). Does it make any difference which way around the Holley goes?

Thanks
 

Terry Oxandale

Skinny Man
perhaps a silly question, but the Holley is best fitted for the mechanical linkage directly off the firewall of a normal American car (front engine, rear drive). Being a mid-engine will require some sort of cable linkage anyway, wouldn't utilizing cable make this a moot point in that you could still pull from the rear of the manifold? Perhaps heat on the cable liner is a problem? If so, then liner-less cables would help that.

That being said, I have successfully used the hole on the other side of the primary axis to reverse the action on the plates. This is on the bottom of the staked linkage plate, but you'll need to ensure clearance because it lies below the bottom of the base.
 

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Mike

Lifetime Supporter
My QF did not have that arm on the bottom so I am modifying the arm to have the same.
 

Randy V

Admin
Lifetime Supporter
I have a nice NOS Holley 650 double pumper I'd like to use on a 347 stroker. The inlet manifold is a duel plane low-rise Weiand.

Question: I'd like to orient the Holley for a forward pull cable (mid-mount engine) rather than rearward pull (forward engine). Does it make any difference which way around the Holley goes?

Thanks
Outside of the linkage issue, it makes no difference at all. Neither the carb or the engine know that they have a front and a back.. :thumbsup:
 
Outside of the linkage issue, it makes no difference at all. Neither the carb or the engine know that they have a front and a back.. :thumbsup:
Apart from the fuel levels sight plugs are at different heights for primary & secondary float levels and the manifold on a dual plane type usually has the primaries biased to the center of the manifold/block along with the carb pad of the manifold is at an angle to match the normal nose up engine installation angle. Sooo if you fit the holley back to front you will need to think outsde the box when setting your fuel levels and you may find that at cruise the primaries might now favour the rear 4 cylinders at which time the engine might just start sending you signals that something is back to front!!! Cliff post a pic of the linkage of your carb and PM me your postal address and I will send you an item that will fix your problem. FOC.
 
I have a nice NOS Holley 650 double pumper I'd like to use on a 347 stroker. The inlet manifold is a duel plane low-rise Weiand.

Question: I'd like to orient the Holley for a forward pull cable (mid-mount engine) rather than rearward pull (forward engine). Does it make any difference which way around the Holley goes?

Thanks
Cliff--you are thinking about it all wrong.

You don't turn the carb around, you just actuate it from below instead of above.

In standard front engine applications, the throttle cable or rod is attached to the linkage on the side of the carb on the left side, some distance above the centerline of the throttle shaft. The cable/rod pulls to the rear to actuate the carb.

In mid-engine applications, such as the Pantera, and GT40, the cable or rod is attached to the linkage an equal distance below the centerline, and pulls to the front.
 

Randy V

Admin
Lifetime Supporter
I missed this post...
Apart from the fuel levels sight plugs are at different heights for primary & secondary float levels ......
I've been working on Holleys for almost 50 years and never observed / realized this... I've got numerous examples in the shop and will confirm...

Outside of this, I've seen a number of carbs installed "backwards" on both single and dual plane intakes with no untoward issues.. I've installed a couple myself..
Linkage can be funny when connecting to the bottom of the carb's bellcrank. Getting the correct angle and correct throw (due to shorter lever length) can be a challenge..
 
Thank you fellas, understood here on all. Very good thoughts and considerations.

I hadn't realized that the angle/level of the Holley could affect running as Jac Mac pointed out....and reversing might affect things (maybe not at Randy has noted). I've got enough variables going on in this build already the last thing I need is a potentially poorly running Holley because it's not sitting at its usual angle. On the linkage I do have the arm extending down below the plane of the pivot axis (as in the pic posted by Terry)....so maybe I'll use that to get the throttle opening in the right direction. Arm is a little short so might have to extend it to get proper throttle modulation otherwise it might be somewhat like a light switch. My 10 year old son gets a kick when I "get on it" with the throttle but it's a drag to drive like that all the time.....

Thanks gents
 
I too will have to look at the float/sight levels Randy I don't think I have any at different levels although I suppose it would be possible on a holley that was made for a production/ factory application. I do know that there can be a difference on accelerator pumps going from a 15-30cc from primary to secondary to prevent a sudden lean condition, power valves squirters jets cam positions all on a double pumper can be different primary- secondary. I don't see a problem running it either direction if you had to, like said with the linkage sorted no need......m
 
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