joepenoso

I can get a Edelbrock 850 #1910 or Rochester 800 cfm( Mid 70s's Buick) for a 455 Olds.
Need to rebuild the stock 750 rochester with cast iron manifold.
Should I stay stock or ....Upgrade to a newer bigger carb.???
Thanks
joepenoso

MDchanic

Stay stock if there's nothing wrong with your carb and if you haven't tuned your engine to way higher revs or way lower vacuum.

- Eric

Run to Rund

Stock is much easier. The big carbs have bigger primaries which won't help gas mileage. The bigger carb would only help in racing, and Olds stockers have gone 10's with the 750 carb. . .

matt69olds

I have the Edelbrock 850 Q-jet on my engine, I love it. If you have plans for future upgrades the the bigger carb might be good. I don't think you can go wrong with any of the carbs if your willing to rebuild them correctly and take the time to dial them in.

droptopron

x2

I like the electric choke too. I know you can retrofit it to any carb but its nice to have.

I am running it on a '69 400 with an edelbrock Performer, stock cam & stock torque converter and it runs really well.

scubastever

go big or go lean.



(that's the worst advice, ever)

cutlassefi

If you're going to use the original iron intake, what benefit would you get by going with a bigger carb, the answer is none.

Stay with the stocker, properly calibrated.

Jmo

Stevec

I have a stock 68 400 and I went with the 600 runs great but I think I could have gone bigger. Are you running an 850? That's not to big? Steve

droptopron

I have it on a Performer and it runs well. I recently had it rebuilt by Everyday Performance and the guy commented that he doesn't know why it is but that carb seems to be adaptable to a wide range of engine set ups with just bolting it on and adjusting it.

One other comment though - It has the fuel line coming into the side (Chevy style) instead of straight into the front so if original appearance is a factor you should keep that in mind.

http://www.everyday-performance.com/

If anybody needs a carb rebuilt he was very reasonable and got it done pretty quickly.

oldcutlass

On a stock manifold it will also require a spreadbore to squarebore adaptor, it's 3/4" taller. So if there are any height requirements, I would go with the stock quadrajet.

507OLDS

We flowed one of those Edelbrock 850's. They don't flow 850,not even close.A typical 455 street engine,with an iron intake or aftermarket dual-plane does not need anything more than 750-780cfm.It will not spin fast enough,or have the potential top-end power to demand anything more.
The 500" Cadillacs were supposed to have an 800cfm carb,& they don't.
The 455 Buicks were supposed to have 800cfm carbs,and they don't either.
They don't need them.

joepenoso

Ok.................................... I'll bite
What did the Quadrajet Edelbrock 850's flow?
What do the GM 750 or 800's flow??
Thanks for everyones opininions and help in this matter
joepenoso

507OLDS

On another note,the Q-jets from the 403's don't flow 850 either.To get one that actually does,you need to look at mid 80's Chevy vans & trucks.
The Edelbrock 850 Q-jet doesn't flow 850.
You will be fine with the carb that you have.