WESCH

Hi

Once agin, I have questions regarding my 68 BB carb.
It is a 4150 double pumper HOLLEY 650 CFM upper body.
Today, I had to take it off the first time due to a leaking acc. pump diaphragme.
Now I saw it has the same primary throttle plate 172 and 2nd throttle plate 173 as the 4110 Holley 750 CFM unit I have.
The upper body of the 4150 unit's openings are quiet a bit smaller in diameter as the once on the 4110.
The 1st pic shows the 4150 and the step down behind the throttle plate, looks like if a bigger carb throtle plate is installed.
The 2nd pic shows the 4110 , same throttle plate , but no step down at all.

So , my question. As we all know that 650 CFM are a bit tight for my 427 CI BB, did the previous owner try to compensate with the bigger throttle plate ?
And did he manage or is this bull...t ?

And my last question. I tried to install the 4110 , but the gaskets are too small. They fit the 4150 perfectly, but are not wide enough for the 4110 .
What gasket do I need to get ?

Thanks a lot. Gunther

Racer16k

A 650 cfm 4150 DP is a -4777, I think. If you have a larger 750cfm 4150 DP that would be a -4779, I think. So gaskets for a 750 would probably work. I'll double check my numbers and edit this post if I'm wrong.


[Modified by Racer16k, 6:36 PM 7/18/2003]

WESCH

Hi

May be a misunderstanding.

The first pic shows the 650 CFM 4150 double pumper, that seems to have a bigger throttle plate installed.
The 2nd pic shows a 750 CFM 4110 double pumper.
As you can see, the sealside of the 4110 has only narrow sealing walls where the 4150 has very whide sealing walls.
The 4110 is suppopst to be identical ( guts ) as the 4150, but the outside dimensions are defenately different.
Just can't locate a gasket for the 4110 in any catalogue.
Only for 4150/4160 and on.

Thanks. Gunther :seeya

Nomad78SA

Gunther,
Don't have a answer for you on your question but I am wondering too.
I have a Holley 4150 DP with the #4777-5 on the throttle tower. Holley and all the books tell me it is a 650cfm. The throttle plate installed is like yours though, 172 primary and 173 secondaries???? The guy who bought it at a Hunter car show swears he was told it was a 750cfm when he bought it for his 67, 427 vert vette. Needless to say I am confused, if the body is a 650 can it become a 750cfm through some other modifications??? I called the Holley tech line and they told me if it has a 650 main body it is a 650.. Here is a link to my thread that has the carb#'s in it and one to a Holley PDF file with all the carbs broke down in it.
Neil in Tenn
Holley
http://www.holley.com/HiOctn/ProdLine/CarbList.pdf

http://forums.corvetteforum.com/zerothread?id=604833




[Modified by Nomad78SA, 2:51 PM 7/19/2003]

WESCH

Hello

So, more people had this glorious idea. :rant:

I measured the intake diameter of the 650 , it is 33 millimeter.
The one on the 750 is 39 millimeter.

So, I don't think it's as powerful as a original 750.

Gunther

WESCH

Hi

Here some logic . :confused:

SUMMIT sells a PROFORM carb upgrate body of 750 CFM.
This is a main body only ,and all 650 and 750 CFM 4150 carbs can be upgrated to 750 by using their throttle plates and bowls.
So I think the throttle plate of a 650 CFM double pumper 4150 HOLLEY is the same as from a 750 CFM, otherwise it would never be possible to convert to 750 CFM by just swapping the main body.
Does this make sense ?

This PROFORM 750 CFM main body sells for 99.95 $ at SUMMIT.
I might try it.

Gunther