Has Anyone Swapped Their Holley Main Body... - Chevelle Tech
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post #1 of 23 (permalink) Old May 19th, 19, 4:35 PM Thread Starter
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Has Anyone Swapped Their Holley Main Body...

for the 134-300 ? Might produce a few more horses ?
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post #2 of 23 (permalink) Old May 19th, 19, 5:01 PM
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jeff
 
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Re: Has Anyone Swapped Their Holley Main Body...

I would like to know the venturi diameter of that part.
I have modified my 4779 to look like that front and rear but a bit more height on the divider in the middle between primary and secondary sides.

I used JB Weld to form the curved entry. Yes I had to grind the stock square entry out until it was gone.
It picked up a lot of power on the 350 I used it on from 5000 rpm to 7000+ it pulled much harder.
No loss of low end..I also enlarged the venturies and polished them and thinned the throttle shafts.
I also used smaller head screws to hold the throttle blades on

Something I do on all my Holleys with the fat throttle shafts.

But I have not tried buying a main body.
Figured If I was buying a replacement might as well try and modify the one on hand.
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post #3 of 23 (permalink) Old May 19th, 19, 5:15 PM
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Re: Has Anyone Swapped Their Holley Main Body...

I did one of those Proform swaps once, when I got done the thing would not idle. Silly me put in the wrong baseplate gasket, replace gasket runs great. 1 month later car idles great but goes like crap, change metering blocks still no help, swap air bleeds, nope, put stock Holley main body back on runs perfect so not sure why it does not work. That's ok though I have other carburetors that work great so no loss except for some time. So the short answer for me is, "no" it didn't work.
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post #4 of 23 (permalink) Old May 19th, 19, 6:28 PM Thread Starter
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Jeff, as I understand it, retrofit body removes all traces of choke, adds replaceable air bleeds and moves secondary idle stop to bottom of air cleaner hole.

As I understand it, makes my 750 DP Ultra a a 750 HP Ultra.
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post #5 of 23 (permalink) Old May 19th, 19, 6:32 PM Thread Starter
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I ordered the Holley part
134-300 SA
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post #6 of 23 (permalink) Old May 20th, 19, 4:47 PM
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Chris
 
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Re: Has Anyone Swapped Their Holley Main Body...

I switched out a proform with my 700 DP carb body and ran fine. Actually ran great on my 355.
[email protected] 113/114
Bought a custom carb and ran........the same!
71350SS and Stokerboats like this.

73 nova,3515#(all steel)Pump gas!(91octane)406ci N/A, best 1/4,1.45 '60,[email protected],10.6 @ 122.38, short shifting,NO tuning!

http://www.youtube.com/watch?v=ng86PsGUcTY
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post #7 of 23 (permalink) Old May 20th, 19, 6:12 PM
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jeff
 
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Re: Has Anyone Swapped Their Holley Main Body...

Quote:
Originally Posted by Reelysalty View Post
I ordered the Holley part
134-300 SA



You do not have it in your hands yet I assume.
If you can measure the venturi diameter I would appreciate it.
Here is a bit of reading on diameters and some air flow testing.
Interesting Holley 750 VS Observation | NastyZ28.com


Thanks Jeff
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post #8 of 23 (permalink) Old May 20th, 19, 7:41 PM
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Ray
 
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Re: Has Anyone Swapped Their Holley Main Body...

Quote:
Originally Posted by jeff swisher View Post
I would like to know the venturi diameter of that part.
I have modified my 4779 to look like that front and rear but a bit more height on the divider in the middle between primary and secondary sides.

I used JB Weld to form the curved entry. Yes I had to grind the stock square entry out until it was gone.
It picked up a lot of power on the 350 I used it on from 5000 rpm to 7000+ it pulled much harder.
No loss of low end..I also enlarged the venturies and polished them and thinned the throttle shafts.
I also used smaller head screws to hold the throttle blades on

Something I do on all my Holleys with the fat throttle shafts.

But I have not tried buying a main body.
Figured If I was buying a replacement might as well try and modify the one on hand.

Do you have dynos to back this up? Only reason I ask is because i did this at track and measured nothing





Leave the carb alone is my take. I would say my opinion but ive tried everything.

Ray
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post #9 of 23 (permalink) Old May 21st, 19, 9:37 AM
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jeff
 
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Re: Has Anyone Swapped Their Holley Main Body...

[QUOTE=Camaro_fever68;11082044]Do you have dynos to back this up? Only reason I ask is because i did this at track and measured nothing





Are you saying you ported the venturies thinned the throttle shafts and removed the air horn at the track?


Took me a couple days to do all that on my carb.
My little 350 engines i use these carbs on like RPM in the 7000 RPM range and higher.
When a engine starts flattening off in power you can feel it.
at 5500 rpm the stock 3310 and 4779 I have would flatten out and by 6500 they were just out of steam and nosing over.


No amount of jet or tuning fixed it.
I tried all kinds of things to make the Holleys pull upstairs.
My Qjet slightly modified and my Carter AFB 750 would pull super hard past 7000 rpm no flattening out or nosing over.


Not one to give up on a carb I had to research the Holley much more and see what people were doing to them to make them really good.
This was nearly 20 years ago.
Seemed the slabbed throttle shafts and thin throttle blades and small screws were some of the ways the fast guys at the track were going so I tried some of that.


Just removing air horn did nothing as far as I could tell so I went deeper.
I really wanted my 750 Holley to run with the other brands of 750's I had.


The 600 edelbrock and 625 cfm AFB and smaller AFB's I have really flatten out on the big end.
And Q jet off who knows what that has the rear secondary door not opening fully will also flatten out on my vehicles

That is one mod I do to the Q jet. Trim the air door stop.
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post #10 of 23 (permalink) Old May 21st, 19, 10:28 AM Thread Starter
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Quote:
Originally Posted by jeff swisher View Post
Quote:
Originally Posted by Reelysalty View Post
I ordered the Holley part
134-300 SA



You do not have it in your hands yet I assume.
If you can measure the venturi diameter I would appreciate it.
Here is a bit of reading on diameters and some air flow testing.
Interesting Holley 750 VS Observation | NastyZ28.com


Thanks Jeff
👍 I should have it next week and will be in touch
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post #11 of 23 (permalink) Old May 21st, 19, 2:53 PM
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Re: Has Anyone Swapped Their Holley Main Body...

Quote:
Originally Posted by Camaro_fever68 View Post
Do you have dynos to back this up? Only reason I ask is because i did this at track and measured nothing





Leave the carb alone is my take. I would say my opinion but ive tried everything.
I have done what Jeff has done with my old 750 and I went from low 11's to high 10.80's after I cut the air horn and re-contoured everything with my 406 years ago.
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post #12 of 23 (permalink) Old May 21st, 19, 6:47 PM Thread Starter
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Quote:
Originally Posted by 68Chevele View Post
Quote:
Originally Posted by Camaro_fever68 View Post
Do you have dynos to back this up? Only reason I ask is because i did this at track and measured nothing





Leave the carb alone is my take. I would say my opinion but ive tried everything.
I have done what Jeff has done with my old 750 and I went from low 11's to high 10.80's after I cut the air horn and re-contoured everything with my 406 years ago.
Outstanding. Holley does not offer a HP carb w/choke horn
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post #13 of 23 (permalink) Old May 21st, 19, 10:43 PM
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jeff
 
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Re: Has Anyone Swapped Their Holley Main Body...

Probably did that stuff before Holley made HP carbs.
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post #14 of 23 (permalink) Old May 22nd, 19, 12:39 AM
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Ray
 
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[quote=jeff swisher;11082328]
Quote:
Originally Posted by Camaro_fever68 View Post
Do you have dynos to back this up? Only reason I ask is because i did this at track and measured nothing





Are you saying you ported the venturies thinned the throttle shafts and removed the air horn at the track?


Took me a couple days to do all that on my carb.
My little 350 engines i use these carbs on like RPM in the 7000 RPM range and higher.
When a engine starts flattening off in power you can feel it.
at 5500 rpm the stock 3310 and 4779 I have would flatten out and by 6500 they were just out of steam and nosing over.


No amount of jet or tuning fixed it.
I tried all kinds of things to make the Holleys pull upstairs.
My Qjet slightly modified and my Carter AFB 750 would pull super hard past 7000 rpm no flattening out or nosing over.


Not one to give up on a carb I had to research the Holley much more and see what people were doing to them to make them really good.
This was nearly 20 years ago.
Seemed the slabbed throttle shafts and thin throttle blades and small screws were some of the ways the fast guys at the track were going so I tried some of that.


Just removing air horn did nothing as far as I could tell so I went deeper.
I really wanted my 750 Holley to run with the other brands of 750's I had.


The 600 edelbrock and 625 cfm AFB and smaller AFB's I have really flatten out on the big end.
And Q jet off who knows what that has the rear secondary door not opening fully will also flatten out on my vehicles

That is one mod I do to the Q jet. Trim the air door stop.




No dude. I didnít do it the track all on one night. I redid my carb with sliced throttle shafts, button Head screws, milled choke horn. And took out the casting marks in the venturiís picked up nothing. The. I a purba k&n stack on it. Picked up a couple tenths
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post #15 of 23 (permalink) Old May 22nd, 19, 12:42 AM
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Ray
 
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[quote=jeff swisher;11082328]
Quote:
Originally Posted by Camaro_fever68 View Post
Do you have dynos to back this up? Only reason I ask is because i did this at track and measured nothing





Are you saying you ported the venturies thinned the throttle shafts and removed the air horn at the track?


Took me a couple days to do all that on my carb.
My little 350 engines i use these carbs on like RPM in the 7000 RPM range and higher.
When a engine starts flattening off in power you can feel it.
at 5500 rpm the stock 3310 and 4779 I have would flatten out and by 6500 they were just out of steam and nosing over.


No amount of jet or tuning fixed it.
I tried all kinds of things to make the Holleys pull upstairs.
My Qjet slightly modified and my Carter AFB 750 would pull super hard past 7000 rpm no flattening out or nosing over.


Not one to give up on a carb I had to research the Holley much more and see what people were doing to them to make them really good.
This was nearly 20 years ago.
Seemed the slabbed throttle shafts and thin throttle blades and small screws were some of the ways the fast guys at the track were going so I tried some of that.


Just removing air horn did nothing as far as I could tell so I went deeper.
I really wanted my 750 Holley to run with the other brands of 750's I had.


The 600 edelbrock and 625 cfm AFB and smaller AFB's I have really flatten out on the big end.
And Q jet off who knows what that has the rear secondary door not opening fully will also flatten out on my vehicles

That is one mod I do to the Q jet. Trim the air door stop.




No dude. I didnít do it the track all on one night. I redid my carb with sliced throttle shafts, button Head screws, milled choke horn. And took out the casting marks in the venturiís picked up nothing. The. I a purba k&n stack on it. Picked up a couple tenths


And I was running a wideband. Lm1
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