classicman

Hi all,
I have a 65 mustang conv with a 289 2V 3 speed. I would like to convert it to a 4 barrel. I know this shouldn't be to hard but one question I have, do I have to buy a new intake manifold to use with the 4 barrel carb? Also I was looking at buying a Edelbrock carb which I heard it is very user friendly. I was told to buy a 500CFM because that is all I will need. Please let me know what you guys think I will need to purchase for the converstion.

Thanks

ky

600 is perfect.

500 would work, but might be a tad bit restrictive.

i know they have 2bbl to 4bbl spacers. and vice versa. but you can find a 4bbl manifold pretty easy. i have an extra one, but the water ports are pretty corroded.

i suggest just upgrading to an edelbrock aluminum performer 4bbl intake manifold. its not hard at all to swap if you have basic car knowledge.

1sweet65stang

intake mani prolly needs replaced im doing the same thing as you im throwing a 650cfm on my 65 coupe 3 speed but my spacer is only set for a 2 barrel......im pretty sure yours is probably the same unless altered befor you bought it

lunarweasel

500 cfm is more than the HiPo 65s had from the factory and won't be restrictive for a stock 289. Will be perfect for you. Just did the 500 Edel myself, comes with a great DVD to help you install. The performer 289 intake is a great option.

Good luck!

ky

no 500 is way too small.

ask anyone on here.

maybe if you want to be a grandpa and get decent gas mileage, then 500 might be ok.

but you should go at least 600 if youre looking for any kind of performance upgrade.

Starfury

Absolutely, completely untrue. 500 is more than a stock 289 will ever need, and will provide great power, throttle response, and efficiency. 600 is too big for even a mild 289, let alone one that's bone stock. The factory Autolite 4100 is (optimistically) rated at 480CFM and it's perfect on a stock motor. Without an extreme porting and valve job, the stock heads won't even touch that flow rate. Even if they could, even at 100% volumetric efficiency you're still not going to pull that much air.

600CFM is way overcarbed on a stock 289. You might be able to tune out most of the hesitation issues you'd run into initially, but you'd still be running an inefficient setup. Yes, vacuum secondaries help, but even the primaries are too big. At that point you're losing vacuum signal to the carb, which results in both poor throttle response and poor fuel atomization. Basically, you're wasting fuel. I have a 600CFM carb on my 320hp 331 and it's perfect. A 170hp motor is not going to use that much carb, period.

500-550 is perfect for a stock 289, and will allow for mild to moderate add-ons in the future. It will provide good throttle response, power, and efficiency through the entire rpm range. You get a stronger vacuum signal with a smaller carb, which results in improved fuel atomization and throttle response. I recommend an Edelbrock for a daily driver as they're easier to tune and lower maintenance than Holleys tend to be.

For an intake, a Weiand 8124 or Edelbrock Performer Plus (aka Performer 289), not a Stealth or RPM, would be ideal. The stock engine doesn't wind up enough to take advantage of the larger manifolds, which are designed for higher rpm operation than the stock engine is capable of handling. Anything larger than the 8124 and you start sacrificing vacuum signal/intake velocity, which is bad for throttle response and efficiency.

jfdfire2

I made the same conversion last year and battled with the same questions. I went with a 600 Edelbrock carb on my basically stock 289 with a Summit racing dual plane intake. I have had ZERO problems with this set up. NO hesitation on acceleration, Fuel mileage is around 15 in town but mostly my fault as I can't keep my foot out of it now. Idles smooth, car runs and sounds great. Good luck with the decision.

RedGTvert

Since you said, ask anyone on here, 500 is not WAY TOO SMALL. As stated above my post, for a basically stock engine it is perfect. I guess that make me a grandpa in your eyes, but my car runs perfect with the stock 4300.