Aloha from Hawaii with an age old question!!

My 66 has a 390 (probably from a 69') with some CAM modification in it- unknown what was done since I bought it off of craigslist and had it shipped to HAwaii. Currently it is running a beat up Edelbrock 750cfm Performer series. I was thinking of going to a 600. It is just nice truck for street driving -not performance. Any suggestions? I dont want to necessarily break the bank and also looking for better MPG. I am not a gear head - but learning! Mahalo!! Rick

 

I am also willing to consider Holly and others!

 

750 is way too much carb for even a race truck with a 390. Just not enough cubes. A good 600 cfm should do you good. I run an edelbrock 1406 and she loves it. Great right from the box. Although I am building a Holley 4160 to run with E85 as well if i want it too. Either way, you have too much CFM

 

I agree - I have no idea why they put the 750 in. It sucks fuel and not a lot of power. It has a Borg Warner T85 overdrive on the tranny -not sure if that matters or not. From what I researched I thought a basic 600 would be fine. Are reconditioned carbs worth the savings? i would think to just get new and not worry about it further...

 

I know my carb is shiny in a very very dirty engine bay, so thats the only real plus. Reconditioned in my opinion are as good as new. Or you can save yourself some money and rebuild yourself (I have yet to work up the gumption to even tear into the holley). The edelbrock is a lot harder to tune though.

 

The Edelbrock is easily tuned and is very flexible. You can order a kit for your carb for about 50.00 which allows a wide range of tuning via an assortment of jets, metering rods, and step up springs. Unless the carb is leaking by or has noticeable play in the rod to case bore where the throttle plates are located the carb is fine. Just remember you can tune down the 750 but if you decide to step up performance the 600 will leave you lacking on CFM.

 

The OEM autolites are excellent carbs, Holley is a very good performer but they typically require some tuning/adjustment, Edelbrock a decent carb for the unbox/bolt on & drive it, summit brand carbs- avoid like the plague- design is great mfg QA runs from good to crap because it is a chinese mfg.

IMHO, check with the local hot-rod guys for a local carb shop.....they can either rebuild yours, sell you a rebuilt carb (autolite, holley) and you will have a very good carb for less $ than buying outright new....your current carb can be tuned specifically for your engine without having to purchase something new....and save $!

 

Bill W and I both had 390s built a few months ago. I reused the 600 cfm Edelbrock I was already running on my 352. I'm getting around 12 mpg in town (with a manual transmission) after having it professionally tuned. Before that it was getting 10 mpg in town. It has good response in the lower rpm range, not so much up around 5000 rpms. Bill put a Holley double pumper 750 on his, which also has a C6 automatic. His cam is a bit healthier than mine. He also had his professionally tuned and is getting about the same mileage as I am, with more power at the top of the rev range. I guess the answer is get the jetting and the timing right, no vacuum leaks, and you can run a pretty wide range of carburation successfully.

 

I'll second that about Autolite carbs like the 2100 and 4100. Many have tried to either copy or improve upon their design for fuel atomization but it is still one of the best. I run two 4100, a 2100 and a nicely done 4300, by Jon Enyeart, which few like.

If you were running a 4bbl then I would put on a 1.12 4100. No blocks as on Holley. Can change out jets in 10 minutes without spilling a drop of fuel. One of the cars has had both an old 1972 Ford Performance Book Holley and the Edlebrock. The Holley was the best of the two while the 4100 beats the Holley in ease of adjusting.