Cam question from Sweden

[Martin]

Hello everybody!
This is a real good forum.
This is my first post.
I bought a deville convertible -69 with a 472 and i´m rubulding the engine and trans. (peanut dish piston)
I´m building it on a budget. It´s a cruiser but i want som ummph when i press down the pedal.
My ideas are stock intake manifold ( cut out the intkes where ther carb sits, if it´s worth it). Build Try-y headers, 2,5 dual exhaust with x-pipe.
My question is how big cam can you put in without do any work on stock heads and if you have any suggestions.
How many Hp do you think I can get?
I´m new to Cadillac but i´m learn as I go.
Thanks in advance.

I think the hardest part is too convince the wife that we need this uppgrades

 

 

[BodybyFisher]

See this.  This is a link to the cam page.  They have a lot of 472/500 performance stuff.  Give them a call I am sure they would have some great ideas.  

https://cadillachighperformance.com/collections/camshafts

Here is their home page

https://cadillachighperformance.com

 

 

[BodybyFisher]

If you can not call them because of your location let me know, Ill call them for you and report back the information 

My guess is, a cam, lifters and valve springs would be a start.  

What fuel do you use?  This engine originally needed leaded fuel.  With unleaded fuels, the heads need to be modified, with hardened seats and maybe guides but the people at the above company would know better.  

[Martin]

I e-mailed them last night but we have 8 hour time differnce i think beetween Usa and Sweden. We´ll see if I get an answer, otherwise I would appriciate it alot.

I use 98 octan with led additive. Thinking about HHo and meth injection at full throttle to prevent spark knock

I´m think about a 600 cfm carburator to get better throttle respons, build my own try-y headers ( do you know whats best. shortys or longtube)

 

Best regards 

Martin

[BodybyFisher]

Whoa!!!! 

Keep in mind the stock carb has primary and secondary throttle bores, the smaller primary is used at low RPM then the huge secondary kicked in up the RPM range.   A 600 cfm will be smaller overall limiting the engine overall.   

I called Rusty at The Carb Doctor / The Carb Source  today and spoke to him about you.   The stock Rochester Quadrajet  in 1969 was 750 cfm.  Rusty at carb source can let you know what the primary is, I forgot to ask him. 

That Quadrajet is a terrific carburetor and no doubt needs a full rebuild.   I used to rebuild Quadrajets every 3 years or so and it made a huge difference in throttle response, fuel economy and power.  If a float or tapered metering rod is mal-adjusted you will have poor performance, but it is NOT due to it being too small.    Rusty agreed with me to leave the stock intake alone and use the Quadrajet.    Another common problem was that the accelerator pump in the carb primary would become damaged and fail to provide a shot of fuel when the accelerator was pressed causing a BOG, or hesitation, which was annoying and dangerous when you needed power. 

You can call or email Rusty, at the link above, he is looking for your email, remind him of my discussion with him regarding your carb.   Consider sending your carburetor to Rusty to have it restored, he knows his stuff and has all parts necessary including brass floats if needed to bring your monster Quadrajet back to life, that is where to start, fueling.   I would not allow anyone to rebuild your carb that isn't 100% familiar with it and who doesn't have full rebuilding kits and parts for it as Rusty has.  If you need me to act as a go between, I would be glad to help.  

I would first have the carburetor fully restored before messing with anything.   I had a 68 Cadillac Coupe deville with 472 and it was a rocket.  Use AC DELCO 45S spark plugs. 

Growing up, the Rochester Quadrajet grew to be my favorite carburetor, I was reluctant at first because I LOVED, the Carter AFB.    When the secondaries opened on these carburators, the sound was amazing.

You may want to look over the EGR/AIR injection systems to see if they can be defeated for more power without harming anything.

[BodybyFisher]

I had an email exchange with Rusty today, he recalled that the primary CFM of the Quadrajet is 275, and 750 overall.