1966 289 build


New Member
Nov 25, 2021
Hey all, I’m looking at building the 289 in my 1966 mustang. I’m planning on using AFR 165 heads, with the upgraded 8605 spring package. I’m planning on using a hydraulic roller cam which I haven’t decided on yet. I’m going to pull the block and send it to a machine ship to freshen it up and balance the rotating assembly. I’ll put APR main bolts and rod bolts in the bottom as well. Along with this I’ll be installing a lightweight flywheel and full roller rocker arms. Right now I have a performer RPM intake and a edelbrock 550cfm carb. I’m planning on using the same intake and carb setup. Im unsure what to expect from this kind of a build, I would appreciate any insight or tips. I don’t plan on taking the motor over 7krpm often. Any recommendations for cam/lifters? Any ideas what hp/tq range this would get me? The car will mainly be a Sunday driver, with the occasional trip to the track. Thanks in advance!
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Active Member
Dec 17, 2021
Those lil 289's have alot of side load stress on the topside of piston skirts and due to those facts and another reason Ill explain I wouldnt use a piston with a traditional teflon style coating on them for street applications...

The method that bonds the skirts to the pistons arent ethanol resistant and over time the oil in the crankcase becomes diluted with ethanol and the skirts start to go bye bye getting beat up by the crank also piston slap rears its ugly head even more than short stroke engines are already famous for.............

Im very partial to getting the pistons hard skirt coated instead if you want to keep the short stroke.....It involves anodizing and other processes,,,,

Id consider upping the stroke a lil and making that 289 a 302 or a 330..

The perfect compression is 10.5:1 but 93 octane will be required..Whats funny is my Range Rover Sport S/C requires premium grade fuel when it was stock. Now its got a 5.3 ls w/twin hairdryers and runs on E-85......LOL

Make sure when you chose a camshaft you use the 128 rule and an engine that is capable of spinning but rarely seeing 7k not too often isnt very streetable either and will require a stall converter and rear gears 3.73 and above thus lessening efficiency aswell as frequency of driving it............

For the street you want a more practical high torque low rpm application with duration under 220 and lift can be raised with 1.7 ratio rocker arms...

My 351w stroked to a 410w has 494hp w/568ftlbs tq from 3300-4300 and 509ftlbs at 5200 rpm's with a camshaft with a duration under 220 w/.477/.493 lift w/1.6 ratio rockers and 111 lobe sep but running 1.7 rail style rocker arms to raise lift to .503/.524" .. Your application w/1.6 ratio rockers and good flowing heads would see around 350hp and 350ftlbs at 5500 on a carb and more if stroked to a 302/330 but best part is you can run highway gears like 2.73 and 3.08's too and raise vehicle efficiency while still having fun with it............

On my vehicle I'm using EDM style flattappet hydraulic lifters that have a lil oiling holes at the bottoms and I also have a special tip that oils my t-chain so I have to run a hp/hv oilpump to make up for the pressure losses but the valvetrain glides and reacts better than a roller camshaft too so I dont need special machining and valve guides to modify my heads to run a roller camshaft in a conventional block if the heads were originally flattappet valvetrain....

When you choose intake gaskets dont use racing gaskets as ethanol breaks them down and turns them to mush...

550 carb seems a lil big as an engine such as yours probably needs around 466cfms actual but will suffice..........

When I used to race charger car class here in Ny rules stipped cars at a 550cfm 2 barrel carb and my engine was spinning 6800-7000 rpm's around an 1/8 mile oval with a 302 Chevy....LOL

Good Luck
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