[mrllmb]

i have a 68 mustang with 289. want to know what kind of rpm's i can get it up to safely. fresh rebuild (now well broke-in) 65 heads shaved,stock valves and springs, gasked port matched.498/500 lift,stock rear end,edelbrock performer rpm intake,600 holley,arp rod bolts,stock c-4 trans.

[samotrx7]

It ought to pull up to 5,500 rpm's no problem. After that it would probably be losing power reving it any higher.

[mrllmb]

thanks for your answer. i was thinking something higher with arp rod bolts and the short stroke it has.

[.boB]

The 289 is famous for living a long time at high rpm's. A well built rotating assembly with that short stroke is the key. Kind of like a motorcycle engine. Look what they were able to accomplish in the 60's.

The key is the valve train. Hydraulic valve trains can be made stable up to about 6,400 or so. But it takes some very carefull parts selection. The average hydraulic valve train starts to float at about 5,800-6,000.

If you want more rpm's, you'll need a solid roller cam and all the right parts.

[Beagle1]

With that lift on a HYD cam and stock springs you will float the valves way before you push the shortblock to it's limit.

My 66 289 HiPo turns 7200 RPM no problem. All stock OEM. Standard bore, stock solid lifter cam, cast iron manifolds. That's just how they ran back then. But they had double springs from the factory.

[mrllmb]

hi 7200 rpm's seems very high. i brought mine up to about 5,000 and that seems like a lot. but if i'm missing out on more rpm's then what do i need to do?

[Beagle1]

You are valve train limited, plain & simple. I think 6000 RPM would be valve float with your set up.

Get the proper springs for your cam. You listed the lift above, but not the manufactuer. All companines have a recommended RPM range and spring for their cams.

Your combo should turn 6200 safely with the proper valve springs, ign. timing and carb jetting.

20 yrs ago we ran a Comp 292H cam. Ported 65 heads on a 289 block. Headers, balanced, 10.5:1, Performer RPM intake, Ford Duraspark ignition.

It pulled to 6800 RPM every week for 2 yrs before it was sold and still used by the new owner.

[mrllmb]

my cam is a voodoo by lunati. i know i need to go with better springs and i do believe i need to do screw in studs also. i will install a set of headers too. my heads only have one spring. i cant wait to hear it scream to 6200. but 5,000 sounded like a lot and i guess thats because this is my first performance build. do i need to go with solid lifters too or hydro will doo? thanks for your help!!!

[Beagle1]

You can go to 6500 with hyd. lifters w/o an issue.

Get the PROPER springs for the cam before your first performance build is your first failure.

Get the headers, the screw in studs and as long as the short block is stout you'll be fine.

[.boB]

You can easily run your current set up to 6,000. You might feel it break up a little before that, that's your valves floating. And that's a bad thing.

If you want more rpm's, you need to make a few "small" changes:

1. Valve springs. You don't need huge seat pressures and triple springs. You just need a good stable spring. Take a look at Comp Cams beehive springs. Low seat pressures, excellent stability to about 6,200-6,400.

2. Rocker arms: Light weight is the key. CC makes a steel rocker that they say is lighter and stronger than alum. It doesn't have to be super strong because you'll be keeping the spring pressures light.

3. Push Rods. Heavy duty, but light weight. Weak rods will pogo, and cause the dreaded valve float. CC Magnums are my choice.

4. Lifters. Now this is where it can get tricky. Roller is clearly the best choice. But that requires a cam change and some expensive lifters. Link bar rollers are about $500 a set! Yikes!

You cannot put flat tappet solids on a hydraulic camshaft.

I would make sure you're using the best quality flat tappet hydraulics you can find. If you're still not happy, then spend the big bux.

Speaking of tappets, make sure there's enough zinc in their diet.

You could switch your cam and lifters over to solids. But then you'de lose a lot of your bottom end. It doesn't sound like you're building a race engine, so I wouldn't recommend that.

[mrllmb]

thanks for all your help guys. i will change out the springs. i looked up the cam i got in it and its a voodoo by linati (61001lk)rpm range is from 1000-5500. is that not a good cam for my 289 because it is able to rev much higher? what happens if i rev higher than that?

[Beagle1]

It will flatten out. Doubt you can get to 6000 with it. Maybe if you were to retard it 8º, but then you would lose all your low end.

You can leave it as is and be happy with it, or change cams. I prefer Crane and Comp stuff.

Your current cam is good for all around. Nothing wrong with it, all in what you want to do.

How fast can you afford to go?

[mrllmb]

i can afford to add a few more things. i want to do a 2500 stall and go with about 3.55 gears in the rear. (2.73's currently) what kind of cams came in the hi-po for them to turn that high from stock (compared to the cam i have or need to get?) thanks

[mrllmb]

no i'm not trying to build a race engine but to be honest, its about me beating my little brother. he's got a 65 ford fairlane 500 (2dr)with a 2000 ford explorer engine (302) that came with the gtp heads. got a cam (about the same as i got but roller)600 holley,stock 4 barrel intake manifold,stock exhaust manifold,stock rear. and he put it on me twice. I cant have my little brother spank my butt like that!!!!! lol.

[RLG34750]

well if beating your little brother is all it's about

gears and a convertor & 100 shot n2o

that will do it....