Brightersiderock

A friend of mine has a 1965 Mustang with a '66 block 289, mild cam, edelbrock aluminum performer intake, Tri-Y headers, a 9'' rear (unsure of gear ratio) and an automatic C-4 transmission. He currently has a 650 Holley 4 barrel carb that suffered a blown power valve due to a backfire. It was to much carb for the car anyway, so he wants to replace it with a smaller CFM carb. He's narrowed it down to three choices, but is not sure which would be best. One is an Edelbrock 500 CFM, Edelbrock 600 CFM, or a Holley 570 Street Avenger. He's reluctant to go with Holley again, and leaning towards Edelbrock, but unsure if the 500 is too small or the 600 is too large. I really do not know much about this, so any thoughts on what would be the best setup for his car?

Randys66gt

Edelbrock 500! A lot easier to work with too. Hope this helps!

jonward786

.570.

Starfury

The 500 is definitely not too small. You can use the 600, but it may take a bit of finicking to get it tuned properly. The 570 Holley would work as well, but is more difficult to tune.

67mustang302

If his Holley blew a power valve then it must have been a really old one. They've been sticking power valve check valves to prevent blow outs in them for as long as I can remember. Besides, intake backfires are operator error anyway.

2+2GT

Get the Ed 500. It'll be responsive and reliable. Even if a newer Holley doesn't succumb to a power valve failure, it's still susceptible to that tried-and-true Holley problem, bowl gasket failure.

Brightersiderock

okay, great i'll pass on the info. thanks for the help everyone

67mustang302

I've never had a bowl gasket fail on me. If you tear them, they'll leak, yes. But it's not the gasket's fault, nor the carburetor's, if you damage the gasket yourself.

1sweet65stang

i got a 600 put it on never tuned runs great...edelbrocks come out well...i have a mild cam and simply bolted it on performer intake and runs great and never flooded i recomend the 600cfm but the 500 will do....

2+2GT

I had Holleys on my daily driver for 15 years, and re-tightening the bowl bolts to get the passages to work right was needed several times a year, and that was with genuine Holley gaskets. I've worked on quite a few, and it's a common problem. I've done my time in purgatory, now I use Autolite or Edelbrock carbs.