What size Carb?

Edelbrock carbs absolutely ROCK and are trouble free. Barry grant stuff is giving a lot of people head aches it seems. Seems like they don't have their air bleeds sorted out, so delivering enough fuel at the right time on a GOOD motor is hard. Plus people at altitude are having difficulties. I know the Barry grant stuff is pretty cheap as well, especially the vaccum ones, but I would not use one.

I like holley or edelbrock.

Problem with edelbrock, there is no 650 in the performer line (only the thunder), 600 is too smal, 750 may not be too bad.

Toma

You'll hear from both parts of holley and edlebrock. I personally had problems with the Holley. I'm running a Edlebrock 750 and works perfect out of the box with no tuning required. My roomate is running 600 Edlebrock with a dual stage Nitrous Setup. That's what I would recommend because when you're not at boost you will be running to much fuel. Good Luck!

Thumper - you and me cover a lot of territory when we post on topics. I have no doubt your car went quicker with more carb - but I don't think the average modded Stang out there is as strong (or revving as high - what do you shift that solid roller at?) as yours. As for your grandson's truck - I have no doubt it ran better with a single than with 2-4's - it was SEVERELY over-carbed, and most dual 4 manifolds are nothing to write home about - especially for street performance. The changes you saw weren't just attributable to the carb change - there was a manifold swap as well. It's not a difficult calculation - even with extremely liberal volumetric efficiency assumptions, the average modded 302 out there twisting in the 6000-6500 range, 650 cfm is more than sufficient to meet the engine's needs for air/fuel -- as you so eloquently put it, if the tune is correct. Also, most of the annecdotal references you make allude to reduced et's - w.o.t. performance. While that's important to me, I also want to know how it's gonna start, how it's gonna run when cold (we're not all down there with you in sunny FL!), how it's gonna cruise, how it's gonna respond in the idle to 2500 rpm range where most street cars spend the vast majority of their time.

So, as to the original posters questions - one thing seems clear; there's lots of opinions out there! Glad I don't have to make a carb selection decision on any of mine. Everything's efi except the bike - and it just works the way it should. If someone twisted my arm and made me put a carb(s) on one of my vehicles, I think I'd fabricate a manifold and put some Webers on it. My experience with them has been the best of any carb'd vehicle I've owned.

Mike your rocking...
The manifold and carb change was on my POS truck, and it did go faster... 100% truth on the 600 carb and street maners, as with the 750 and street maners, the primary venturi's are all that is used most of the time, and the vac secondary when the engine requires it!! as for my cam and hi revs... yep, it is a flat tappit solid cam and I shift at 7K, and yes, the larger cfm is better for a higher reving engine.. ( as i above 6K)... but in the 60's it was "assumed" that the fastest a car would go was 180 mph, the engine and cams and heads and intakes have gone a long way since those asumptions... and in all fairness pull the 600/650 and go to a vac secondary 750 and you WILL be faster... and I have no reason 'cept it works!!!! and I have put a lot of the smaller carb boys back in the parking lots with my 289s and 302s with the Holley 780/750 list 3310 series carb..... oh, the only F/I I have is my Mini!! everything else is Carb.... for over 35 years of racing, and experimenting...cool??

Just me.............................

Thumper

PS he wants a 300 HP NOS engine....

We'll just have to agree to disagree on this one.....that's ok though....it's all good. Later....

Wow, two of the most knowledgeable guys on this board dissagreeing.......interesting, lol

Actually - I don't think we're really that far apart. I think Thumper's experience comes more from higher revving, more powerful, race oriented motors. They can often take advantage of a larger carb. I'm trying to relate to the original poster - who I think has a relatively average modded 5.0L - less power, less rpm, and street with occasional strip. Will a 400-450 HP 302 spinning 7000-7500 benefit from the 750 vs. 650? Probably. Will a 300HP 302 spinning 5500-6000 rpm benefit from a bigger carb? I believe the 600-650 cfm carb is more than sufficient.