[tech] Old Skool help req'd

[pred8r]

Old Skool question;

Does anyone here know if youll get better fuel economy and power by using a quadrajet carby instead of a 650 holley on a 302 Cleveland?

Considering the quaddy is self-metering on fuel and can flow around 900CFM as opposed to the Holley which only flows 650 and just pours the stuff in (Almost like they had shares in an Oil Co.)

Ive never heard of it being done, and just wondered if anyone else had and what results were obtained.

Warning: This is an Old Thread This discussion is older than 120 days. information contained in it may no longer be current . Please think of the children before resurrecting this ancient thread!

[Turblue]

YES...!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

If properly tuned. There are a hell of a lot of tricks with the quaddie that improve performance etc. I may even still have my old HP book on the quaddie.

Accelerator pump mods, metering rods, etc....

They are a great carb. A classic spreadbore. I loved it on my old 308.

By now they would be very long in the tooth, and hard to get parts for, I would have thought. Carter made a carbie based on the quadrajet. It was an all alloy job that was great.

Dude, you are talking my era..!!!

[pred8r]

OMG!!!! someone who can speak venturi!!!!!

[Turblue]

Yes, there was life before fuel injection..!!!!

I spent a lot of time tuning the quaddie and the Carter. I had tune up kits with various rods, hangers and jets. Even a set of wire drills and diamond files.

I may be a geek now, but was a tuner then......

[pred8r]

no, not geek......old skool.....like me.....i just like cars AND computers....not a geek.....no......not.......geek

[MatsHolden]

I loved it on my old 308.

mmmm 308. Love em.

Never late in a 308! V8 muscle so much more exciting than 4 or 6 cylinders.

[xplosv57]

Well youre never gonna get ridiculously good fuel consumption out of any carby V8 so id sacrifice a few l/100kms for the power increase of the Holley!

[Turblue]

A Holley is like using a sledgehammer. They have pretty rough metering.

Quadrajet is more accurate and still very capable.

[pred8r]

Well youre never gonna get ridiculously good fuel consumption out of any carby V8 so id sacrifice a few l/100kms for the power increase of the Holley!

Yeah, what Turblue said

You can get good economy and ok power, or a rocket and need shares in BP. EFI is really not much different - it mostly just stops people 'fiddling'.

This is why i asked the question. Holleys litrally flood the engine with fuel, the Quaddys are a MUCH better and SO MUCH simpler design at doing what they do. But I've never heard of one being run on a Clevo (Ford is Carter/Holley, GM was Quadrajet/Rochester) and was wondering if there was a reason. These days an adapter plate is $200 and 10mins on a CNC mill so not really an excuse.

Urban Legends are a wonderful thing.

Have you installed a pod filter and 3" zorst yet? hehehe

[Wraith]

Old Skool question;

Does anyone here know if youll get better fuel economy and power by using a quadrajet carby instead of a 650 holley on a 302 Cleveland?

Considering the quaddy is self-metering on fuel and can flow around 900CFM as opposed to the Holley which only flows 650 and just pours the stuff in (Almost like they had shares in an Oil Co.)

Ive never heard of it being done, and just wondered if anyone else had and what results were obtained.

A good question that's more easily answered depending on exactly what's done to that 302 you have and exactly what type of 650 holey we're talking about as well, ie : spreadbore, squarebore, vac secondaries, mechanical secondaries, double pumper etc........but in short you'll definitely get better economy from the quadrajet as it is a spreadbore vac. seconcondaries carb and was made this way for low end response and cruise economy.

From what you say above I'm assuming the 650 is a double pumper, if so it will only run well on a "worked" 302 and needs to be metred correctly.

A double pumper 650 Holley on a "stock" 302 will not run as good as a vac. secondary carb, it'll simply flood the engine.

What you should get a hold of is a Carter AFB, these were Ford factory units on Cleveland V8's and run as well on them as Quadrajets did on GM Chev and Holden V8's.

Edelbrock also made a copy of this carb with better metering options built in.

Quadrajet was a great carbie, with vac. secondaries and the Aust. version could flow to 780cfm - don't worry too much about the cfm figure, 650cfm is still enough flow to feed a 500hp small or big block V8.

Guess I'm showing my age here, but this topic brings back strong memories of my old 9 sec. 350 chev powered XU1, which was fed by a Phil Soderstrom built Holley 1050cfm dominator squarebore double pumper and made 593BHP (atw), interesting thing is the dyno readout which showed at 6250rpm, the cfm requirement by the engine was only about 620cfm.