intake / carb upgrade question

[Andy4802]

Hey all,

i am getting started on some work on my 1980 Stepside. It has a non-stock 350 with a 4 bolt main and 4 barrel Quadrajet. i found a good deal locally on a 650cfm holley double pumper that has been completely rebuilt. The seller also has an edelbrock performer RPM intake (both items are square bore). aside from changing the carb and (possibly) intake, the only other performance mod that i am planning (for now) is headers and dual exhaust. i am not planning on changing out the cam.
My question is this: Will that intake and carb combo work well with stock cam? OR should i just use the stock intake (with blockoffs on EGR and Hot air choke) and install the carb only?
i'm going to use basic vacuum only and am planning on removing or not using emissions equipment.

thoughts?

[Stewart G Griffin]

Thoughts?

My thoughts are, why when anyone gets a nice stock chevy they are compelled to change the carb and intake?   Everybody in the whole world does this.   i mean everybody!


i'm not saying don't do it, i'm just stating my thoughts.

[Andy4802]

Thoughts?

My thoughts are, why when anyone gets a nice stock chevy they are compelled to change the carb and intake?   Everybody in the whole world does this.   i mean everybody!


i'm not saying don't do it, i'm just stating my thoughts.

i meant thoughts on the 2 options i presented. the quadrajet is finished and i have no plans on rebuilding it.

[eventhorizon66]

To be clear, you are asking whether you should:

1) Keep the intake and switch to the Holley

2) Switch to the Holley and the Edelbrock Performer RPM

If those are the only two options, I would most certainly recommend option 2.

[Andy4802]

To be clear, you are asking whether you should:

1) Keep the intake and switch to the Holley

2) Switch to the Holley and the Edelbrock Performer RPM

If those are the only two options, I would most certainly recommend option 2.

yup you got it ,those are the 2 options i am considering.... my concern was if it would be ok to use that intake with the stock cam.
#2 is the option i am leaning towards as wel... 

[eventhorizon66]

my concern was if it would be ok to use that intake with the stock cam.

It would be ok, but they aren't well matched.  That RPM intake is probably tuned to make peak torque around 4500 rpm and the stock cam probably makes peak torque around 3000-3500 rpm.  But my main concern would be the mismatch between the holley carb and the q-jet intake.  And adapters kill power.  You stand to lose more power everywhere if you try to adapt a square bore carb to a spread bore intake.

If the engine will keep that stock cam.  My favorite choice would be option 3: keep the intake and rebuild the Q-jet.  Unless someone has smashed it with a hammer or it caught fire, it is not trash.  It can be rebuilt and tuned to run much better than when the engine was new.

[1980c10]

the q-jet is great when tuned properly and does better on fuel economy and depending on your q-jet it may flow better than 650 cfm. A lot was done by Gm for the q-jet in an attept to avoid fuel injection. They are more complicated than an aftermarket carb but talk to a good carb guy b4 making a decision. I have mine set up by a carb guy but I have him set up timing vacuum etc to work together and my trucks always leave there running like new and getting pretty nice fuel economy for what they are. Just my opinion I don't think you should so easily dismiss the q-jet just becuase many others do.