Carb size

Is a 600cfm edelbrock a good choice for a 302 that has been bored out to 312ci ? the motor has a mild cam and stock manifolds

 

Not my first choice, but yes it'll work.

 

You may be alittle lean on top end but for just driving you will be fine.

 

I have a 600 Holley vacuum secondary (66 jets). 3.25 gears and 4500 stahl. I have limited time on the carb, but I have ran it pretty hard a couple times on the street and it has not stumbled once.

 

http://www.holley.com/applications/CarburetorSelector/CarbSelection.asp

 

I think I gave it my best shot with the edelbrock and didn't know it was performing poorly until I put on a holley 600. I bought the edelbrock brand new and the holley was a used that I rebuilt. so I would have to say holley

 

What bore does it take to make a 312? Ive never seen it bored to that, just 310

 

This all depends on what the intended purpose of the car is. For a street car the Edlebrocks are my choice. They run well and don't have issues with hunting idle and inconsistent light load metering the Holley's are prone to.

If you are looking for the carb that will give you the most performance the Holleys are a better choice. I assume this is a street car as you're using the stock manifolds as such 600 CFM Edlebrock is a good choice.

Just one thing. If you plan on making decent power from the car (300+ HP) you can keep the 600 until the rest of your mods are done but it will become too small as you upgrade other parts to make more HP. So be prepared to replace it in that event. Unfortunately a carb is not something you want to grow into so putting a 780 DP on that motor because you plan on making 400 HP in the future would be a big mistake.

 

my car is only intended to be a street so i will go wth the edelbrock. the engine was bored 060 ovr. the mechanic estimated it would be 312 ci.

 

Unless it's a Mexican block, FRPP, or Dart block it will be a pile of scrap before too long.

 

While I would never bore a 302 to .060 over I know of several guys running these (early blocks) on their STREET cars. The only issue is they run a bit hotter. I'm not sure if the Mexican is even a candidate for a .060 race motor but this brings up an opportunity. I have a Mexican block bored 30, an early block bored 30 and a standard bore 5.0 block in the garage. Looks like I'll get out the sonic tester and see what the differences are.

Of course there are wide differences no matter what the vintage of the block as there is no telling where the casting had shifted to when the block was cast. Thus a SONIC check is needed on any factory block when going more than .030 over.

 

If the enine was checked to make sure the core hadn't shifted during the casting process then .060 over is doable. I prefer .030 over as a maximum but as mentioned there are quite a fer .060 over blocks that run fine on the street.

 

the block was built back in 68 or 69

 

Gee, I never have had those problems.

 

well if the 68 302 we put in the car turns out to be a bad apple i have a plan b