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Holley carb on my spread bore 440 manifold.

Iceman55, just thought of something, check the throttle bore diameters of the adapter you pick. Now that I think of it, some early adapters were sized for the smaller Carter & small Holley carbs. You want one for the larger Holley throttle bores.
 
Iceman55, just thought of something, check the throttle bore diameters of the adapter you pick. Now that I think of it, some early adapters were sized for the smaller Carter & small Holley carbs. You want one for the larger Holley throttle bores.
 
Thank you for the input it is very helpful.
0311192201_HDR.jpg
 
welcome to FBBO from NorCal Sierras

Holley makes a
#4165 mec. sec. 650cfm #0-6210
or #4175 vac. 650cfm #0-9895
spread-bore dbbl pumper or vac. sec. carb too

they use to have larger cfm version, call them & ask them
1-866-464-6553

Chevy's used them,
IIRC, I think some were as big as 830-850cfm
on BB's mostly, some 350hp SBC & some (vettes) BBC's too

there's also the "new" Street Demon carbs
IIRC can be had in spread-bore replacements for
GM/Quadrajets or Chr./Thermoquads style baseplate

If an adapter is a height issue


but;
that doesn't look like a spread-bore/Themoquad
small primary & large secondary manifold
looks like a square bore, both bores are the same size
 
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welcome to FBBO from NorCal Sierras

Holley makes a
#4165 mec. sec. 650cfm #0-6210
or #4175 vac. 650cfm #0-9895
spread-bore dbbl pumper or vac. sec. carb too

they use to have larger cfm version, call them & ask them
1-866-464-6553

Chevy's used them,
IIRC, I think some were as big as 830-850cfm
on BB's mostly, some 350hp SBC & some (vettes) BBC's too

there's also the "new" Street Demon carbs
IIRC can be had in spread-bore replacements for
GM/Quadrajets or Chr./Thermoquads style baseplate

If an adapter is a height issue


but;
that doesn't look like a spread-bore/Themoquad
small primary & large secondary manifold
looks like a square bore, both bores are the same size
 
welcome to FBBO from NorCal Sierras

Holley makes a
#4165 mec. sec. 650cfm #0-6210
or #4175 vac. 650cfm #0-9895
spread-bore dbbl pumper or vac. sec. carb too

they use to have larger cfm version, call them & ask them
1-866-464-6553

Chevy's used them,
IIRC, I think some were as big as 830-850cfm
on BB's mostly, some 350hp SBC & some (vettes) BBC's too

there's also the "new" Street Demon carbs
IIRC can be had in spread-bore replacements for
GM/Quadrajets or Chr./Thermoquads style baseplate

If an adapter is a height issue


but;
that doesn't look like a spread-bore/Themoquad
small primary & large secondary manifold
looks like a square bore, both bores are the same size
Agreed, looks like a square bore to me. Mine was waaaaay different with clearly noticeable size differences. You might want to find a gasket that fits the carb then lay it on the intake and compare because it looks like that Holley should bolt right on.

Also I noticed a large machine gasket surface on the left, sit your Holley on there and make sure none of the linkage hits that surface preventing it from sealing.
 
0311192103_HDR.jpg
I am learning a lot putting the gtx together. I enjoy restoring parts but am learning the mechanical as I go along. The manifold could be a spread bore as you say but I still have clearance issues. I believe it is the sec pump cam that is hitting the manifold.
Meant to say square bore as you say. I did not think it was a square bore because of the 4 round bores.
 
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Iceman55, just thought of something, check the throttle bore diameters of the adapter you pick. Now that I think of it, some early adapters were sized for the smaller Carter & small Holley carbs. You want one for the larger Holley throttle bores.
 
Thanks, I will see if purple brewer's trick will help to see if there are clearance issues.

Sorry purple beeper!
 
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View attachment 733287 I am learning a lot putting the gtx together. I enjoy restoring parts but am learning the mechanical as I go along. The manifold could be a spread bore as you say but I still have clearance issues. I believe it is the sec pump cam that is hitting the manifold.
(Meant to say square bore as you say. I did not think it was a square bore because of the 4 round bores.)
 
Again "spread bore" refers to 2 small primary throttle bore with 2 MUCH larger secondary bores. I forgot about the linkage interference problem. A 1/2" spacer/adapter takes care of that. The '70 manifold should have the correct carb mounting bolt pattern. As said, use the Holley gasket to verify both carb & manifold bolt patterns match, turn 90* to be sure.
 
Again "spread bore" refers to 2 small primary throttle bore with 2 MUCH larger secondary bores. I forgot about the linkage interference problem. A 1/2" spacer/adapter takes care of that. The '70 manifold should have the correct carb mounting bolt pattern. As said, use the Holley gasket to verify both carb & manifold bolt patterns match, turn 90* to be sure.
 
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