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'66 GT 289 A-Code Rebuild

New User
Posts: 5
Joined: 10/13
Posted: 10/29/13 12:43 AM

Hello, My first post on the forum. I have tried to read as many posts as I could prior to asking my question about 289 engine rebuilds. I am not very knowledgeable about the compatible inner workings of an engine.

I am about to start purchasing the major component parts needed to rebuild my 289/4V A-code engine. I am not rebuilding my Mustang as a concourse correct, and I do not want to rebuilding it as a restomod. But I would like to rebuild it as close to time period plausible as I can, with parts that were available in the late 60s if possible. I also wish it to be fun to drive, but not a street racer/high HP monster. With that said what would be the ideal Cam, intake, and heads to use. I know that I want to keep my Autolite 4100 Carb (1.08 Venturi) and have been thinking of installing the triple Y exhaust. But what parts are compatible with them?

I have looked at the HIPO, Shelby, and the Eddlebrock F4B Intake manifolds. But I cannot find anything that tells me that they are compatible with the 4100 Carb. Also, what aftermarket heads were available at the time? I know the HIPO heads were available. I know they can still be found and purchased. But are there any others that are ideal? Lastly would be the CAM. Something that improves the original A code 289 and works with the other parts.

Thank you for your input.  
1966 GT
Tahoe Turquoise

Post Reply
Posts: 648
Joined: 07/06
Posted: 10/29/13 07:49 AM

The small block FORD 4 bbl., all HIPO, Shelby, and the Edlebrock F4B Intake manifolds will take the square flange of any Ford 4 bbl carb. I have an Edelbrock Performer, an Edlebrock F4B, and my original S2MS COBRA intake and they all have the same square flange and holes. Not like GM and Mopar and with some spread-bore carbs with huge secondary butterflies.

The original G.T.350, 289/306hp, HiPo cam was a .457" lift, with 306° duration. I used a Crower .465" lift with 292° duration, back in 1975, when the lobes started wearing off. It had virtually the same feeling as the original cam but the vacuum signal dropped way down account of the overlap of the intake and exhaust timing. The Right cam depends on the vacuum needs of your current engine. Pure HP/Performance has little need of vacuum because they are designed for WOT, pedal to the metal, with no vacuum advanced distributors or accessories found on street drivers.

Note: Because of lower vacuum, carbs that employee vacuum power valves and metering rods MUST be changed out to match the current vacuum. Holley recommends: Current vacuum signal reading divided by half, plus .5. If your vacuum reads 8, then you need a 4.5 power valve, so that the power valve doesn't dribble gas by it's orifice due too weak vacuum and too strong a spring, like an 8.5 (which is about stock), causing a rich idle situation. Ask me how I know. Smile))

Your cam company will need to know rear ratios, tranny, and lots to get you what you need. Nothing is worse than a camshaft that is chosen emotionally and not comprehensively.

Does that make sense?  

Post Reply
Posts: 86
Joined: 07/13
Posted: 10/29/13 10:25 PM

I also wish it to be fun to drive, but not a street racer/high HP monster.

there are no real aftermarket heads from the 60's

hi po heads are just stock heads with machined spring retainers.


gearing will increase your acceleration more than anything else.

use 3.23 for street and long 70 mph fwy trips

use 3.43 for better acceleration but lower fwy speeds like 66.

use 350 for shreddin the street and 62 mph fwy speeds.


there are no real aftermarket heads from the 60's

hi po heads are just stock heads with machined spring retainers.

pocket port them

install chevy in or ex valves [forgot which]

backcut intake valves.

install screw in studs.


CARB - buy a ford 1.12 carb or holley 600.

CAM - run a comp 265deh or xe262 cam.

RODS - Install arp bolts, shop peen them and resize or buy scat or eagles.

ENGINE BALANCE - Get it done.  

Post Reply
New User
Posts: 5
Joined: 10/13
Posted: 10/31/13 10:35 PM

Thank you for the information, I will keep it in mind while I am planning my rebuild.  
1966 GT
Tahoe Turquoise

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