[Blissim]

I have a 66' 289 in my 65 mustnag. its bored to a 292, balanced, 3/4 race cam, high compression pistons, 4 bolt main, high rise aluminum intake manifold and a 4v eldabrock 650 carb.

The heads are stock and not even rebuilt. The car isnt fast enough for me. With everything thats already done to the engine what did you think is the best way to go? Supercharger? Turbo? Nos? Suggestions plz.

 

[Rickmaan]

Definitely heads. With a good intake and aftermarket cam, the difference a good set of heads will make will be like night and day. IMO, the AFR 165 are about the best flowing you'll find without being so big to kill off low rpm response which is something you need to be careful of with your short stroke engine, but if you're on a tighter budget than that there are a few aluminum heads under $1000, and any one of them would be 100% better than stock 289 castings. Just be careful about how big the ports are in the heads you get, the short stroke long rod combo of a 289 doesn't need alot of port volume to reach high rpms and big ports will quickly loose port velocity at low rpms which can make the engine feel sluggush. Since you're in CA, you might also want to look into Power Heads cnc porting on your stock heads. They've been able to get flow numbers close to aftermarket heads with the relatively small port sizes dictated by the oem castings. That means high port velocity and good low rpm reponse while still flowing well enough to make a big jump in HP.

 

[rusty105]

I have a 66' 289 in my 65 mustnag. its bored to a 292, balanced, 3/4 race cam, high compression pistons, 4 bolt main, high rise aluminum intake manifold and a 4v eldabrock 650 carb.

The heads are stock and not even rebuilt. The car isnt fast enough for me. With everything thats already done to the engine what did you think is the best way to go? Supercharger? Turbo? Nos? Suggestions plz.

Definately need more info. What cam? What Intake? Compresion ratio? if you are serious about more power check this out. . It is a stock bottom end 289 with the right combo of parts on the top. BUT it goes against what every body will tell you. Every one will say the heads are too big, the carb is too big, intake too big, etc... BUT it is hard to argue with results 427 HP @7000RPM, 355TQ @5700RPM, on pump gas, from a 289 N/A with NO power adders.
That said.... don't go over there with only the info you posted, they will chew you up. have an open mind and they will give you the world. Most of the frequent posters and Admins, and Mods are Pros, and do this for a living. And they all race their junk, so the combos are well proven.

Oh, BTW, nice hood on the coupe irate: Who makes it. i may need one for my '65 coupe.


Rusty
ps, you may want to check into that 4 bolt main thing. I am not sure any 289 came with a 4 bolt main.

 

[68RCodeConv]

What tranny do you have? Auto with a really tight converter?

What gears do you have? 2.79? 3.00?

If you have really steep rear end gears and/or a really tight converter (low stall speed) then a 289 with a big cam will be a real dog. It is not going to make much power below 2500 and the gears/converter are holding you down in that power range for too long.

If you have steep gears change to something in the 3.5-3.9 range before investing a bunch of money in the motor.

 

[zray]

I vote for new heads also. ARF 165's might be a good way to go. Do some research on what's available.

http://airflowresearch.com/articles/article051/A-P1.htm

after you have the breathing capacity, then think about supercharging, etc.

Z. Ray

 

[HoosierBuddy]

I put AFR 165's on my 289 and it ran great.

That worked for me for a while until it still wasn't enough power so I put in a 347.

My suggestion? Save your money and replace the whole engine with a 331 or a 347. You can put some nice heads on it...likely AFR 185's. Your intake and carb would transfer if you still want to use them.

Phil

 

[Blissim]

I dont know any info on the compression and the tranny i bought from a junkyard which is it t-5 and they didnt know any info on the ratios or anything.

I dont want to take the 289 out i just want to know the best things to do to it. Im putting head on for sure. How was gt-40 heads. Someone told me their like cobra heads.

 

[zray]

I put AFR 165's on my 289 and it ran great.

That worked for me for a while until it still wasn't enough power so I put in a 347........................................."


Phil

It's funny how fast we can get used to having more power, then want more. I wonder if the astronauts are saying, " you know, that 5 million pounds of thrust just isn't cutting it anymore..."

 

[HoosierBuddy]

You probably will not be able to just replace the heads on your 289.

Two major issues arise in trying to do so.

1. All of the modern heads have much bigger combustion chambers than stock 289 heads. If you just take off your old heads and put on GT40's you will kill your compression ratio and your engine will make less HP instead of more.

2. If your pistons are stock, without valve reliefs, the larger valves on a modern performance head will hit your pistons, ESPECIALLY if you upgrade the cam to a performance grind...which you would definitely want to do.

The long and the short of it are if you want to replace your heads on a 289 you should plan on:

- new cylinder heads (complete with valves, rocker studs and pushrod guideplates)
- new head gaskets
- new pistons (pop ups with big valve reliefs. I was using KB116's on my 289)
- piston rings
- new cam (Comp extreme energy is a nice line of cams)
- new rocker arms (stud mount adjustable, roller rockers)
- new pushrods
- new valve covers (stock ones won't clear roller rockers)
- new valve cover gaskets
- new hardware for above

That's MANDITORY beyond that you should consider

- The cylinder walls may be in poor condition and might need rebored before installing new pistons.
- The oil pump should probably be replaced while you have the engine apart.
- I'd replace the timing chain assembly.

Plan on roughly 3 grand to swap on a new set of heads. That's if you do all the work yourself and nothing major goes wrong.

Phil

 

[Blissim]

You probably will not be able to just replace the heads on your 289.

Two major issues arise in trying to do so.

1. All of the modern heads have much bigger combustion chambers than stock 289 heads. If you just take off your old heads and put on GT40's you will kill your compression ratio and your engine will make less HP instead of more.

2. If your pistons are stock, without valve reliefs, the larger valves on a modern performance head will hit your pistons, ESPECIALLY if you upgrade the cam to a performance grind...which you would definitely want to do.

The long and the short of it are if you want to replace your heads on a 289 you should plan on:

- new cylinder heads (complete with valves, rocker studs and pushrod guideplates)
- new head gaskets
- new pistons (pop ups with big valve reliefs. I was using KB116's on my 289)
- piston rings
- new cam (Comp extreme energy is a nice line of cams)
- new rocker arms (stud mount adjustable, roller rockers)
- new pushrods
- new valve covers (stock ones won't clear roller rockers)
- new valve cover gaskets
- new hardware for above

That's MANDITORY beyond that you should consider

- The cylinder walls may be in poor condition and might need rebored before installing new pistons.
- The oil pump should probably be replaced while you have the engine apart.
- I'd replace the timing chain assembly.

Plan on roughly 3 grand to swap on a new set of heads. That's if you do all the work yourself and nothing major goes wrong.

Phil

Lol thanks for all that but if you didnt read everything i posted that ive alreayd done to my engine its freshly rebuilt with around 9k miles. it was bored out, high compression pistions and a 3/4 race ram. How would better heads make my engine perform worse???? So thanks for all that but everythings already done.

 

[frdnut]

Lol thanks for all that but if you didnt read everything i posted that ive alreayd done to my engine its freshly rebuilt with around 9k miles. it was bored out, high compression pistions and a 3/4 race ram. How would better heads make my engine perform worse???? So thanks for all that but everythings already done.

What brand or model intake are you running?
What is your compression ratio now?
They may be high compression pistons with 289 heads with 54cc chambers but when you throw on an aftermarket set with 60ccs or more your compression might not be so high anymore..
The smallest "popular" aftermarket chambers I have seen is 58ccs..
Saying you have a 3/4 cam is meaningless?..It's a very old school term that nobody seems to remember what it was referring to?.3/4s of what?..What is full race?...Lift and duration at .050 are the specs that will give you some meaningful info..
Love the look of the car..Cowl hood looks mean!