650 double pumper with an automatic

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1968dartman

1968dartman

life is getting better!!
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I have a chance to get a Holley 650 double pumper but I am not sure if it will work ok on my 340. I have a 340 with 13:1 pistons, purple shaft cam and a performer rpm intake. As far as I can see the convertor is stock which is what worries me. I am running 355 gears. What can I expect if I try the holley. The carb I am running now is an eddy 750 which works well
 
IMO, not worth the effort, you won't gain anything.

Edit: I guess I should elaborate. Any improvement the double pumper design has is negated by the fact that it's a smaller carb. I'd say if anything they'd probably flow about the same. With no flow increase all you'd be doing is just changing the way the car feels to drive, and if that is the case it's just not worth it, in my humble opinion.
 
1968dartman said:
I have a chance to get a Holley 650 double pumper but I am not sure if it will work ok on my 340. I have a 340 with 13:1 pistons, purple shaft cam and a performer rpm intake. As far as I can see the convertor is stock which is what worries me. I am running 355 gears. What can I expect if I try the holley. The carb I am running now is an eddy 750 which works well
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Any head work,(new heads,aluminum?). And what cam?Are you willing/running ,race gas/e85/alcohol?.
 
I agree with UOP. And with the stock stall converter it might be a bear to tune. Probably have to go pretty big on the secondary shooter and pump cam or it'd just bog off the line. If your 750 Eddy is working good I'd leave it be. If you want to make a much bigger improvement look at swapping in a good high stall converter. The stall needed will depend on what cam you have and BTW: saying your engine has a purple shaft cam means absolutely nothing. Not worth the effort of typing it in. Reason being there are numerous purple shaft grinds all the way from really small, almost RV size, up to full race/oval track cam grinds. Anytime you describe a cam you need to at least tell the duration at .050" and the total lift or no one has an idea what size your talking about.
 
Since the rest of the combo looks like a jumble of random parts, why add to it? Sounds like you need to pick a direction with that combo and get all the parts moving in the same direction, with the same goal in mind....JMO.
 
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