68 289 engine rebuild question

[tycooley]

I want to freshen up my 289 and get a little more power from it. Any ideas?

[bartl]

Give us an idea of what you're starting with.....

If it's a stock 289 in fairly decent condition, but time for a rebuild then I would do the following:

1. Minimal overbore to "freshen" cylinders, preferably .030 or less.
2. Since you're buying pistons anyway, select some that will provide a minimum of 10.0:1 static compression ratio with a good quality piston ring. If you're not going to be pounding on it then hypereutectics are fine.
3. Have the crank ground .010/.010 rods/mains under and polished. Buy a good quality set of tri-metal bearings.
4. New oil pump (standard volume) and pick-up, and H-D oil pump driveshaft.
5. C9OZ-6250-C Hydraulic flat tappet camshaft with a single true roller timing chain and a new fuel pump eccentric.
6. DIY porting (mostly removal of the thermactor "bump") and port matching of your OE cylinder heads. Have hardened seats installed and move up to either 351W valve size (1.84/1.54) or SBC valves (1.94/1.60) with screw in studs and good quality springs and locks. If new pushrods are needed (probably due to length) use hardened. I would probably stick with a 1.6:1 steel roller tipped rocker arm.
7. I'd use port matched reproduction HiPo exhaust manifolds into a 2.5" exhaust.
8. Port matched Weiand Stealth Intake with a 1.12" Autolite 4100 4V carb on top.
9. Have your OE distributor checked and new bushings installed, if needed, and recurved to BOSS302 specs.

That should get you something reliable with, I'd say, at least a 40% power gain over a stock C-code engine.

[2manyhobbies]

if you just want a little more power from it and to make it a great driver, go with something like a comp cams 257H cam, edelbrock performer intake, some tri y headers, and some form of electronic ignition. Keep the bottom end stock, flat top pistons, then you don't have to put premium in it.

[cmefly]

Originally Posted by tycooley

I want to freshen up my 289 and get a little more power from it. Any ideas?

Easy, Stroke it out to a 347. If you want more power you need cylinder heads that flow better so either do some port work and bigger valves on your heads or buy some TFS 170 heads. Stock ford heads need the most work on the exhaust side, so if your on a budget focus on that side. Get a good dual plane intake. I would go with a STEALTH or RPM intake or Air Gap but the Air Gap is more money for no gain on your application. You will also need a larger cam. Tri y headers would be a good choice or 1 5/8 long tube.

[slim]

Originally Posted by tycooley

I want to freshen up my 289 and get a little more power from it. Any ideas?

Is it 2V (C code) or 4V (A code). 3 speed manual, 4 speed manual or automatic (C4)?

Daily driver you probably want more low end torque. IMHO many changes that give more stated horsepower show up at high rpm.

68 C code is the lowest compression Mustang V8 prior to the 72/73 plunge. An increase in static compression to say 9.5 would be good. If it's an automatic a step up (numerically) in the rear axle ratio to say 3.25 will give a big kick in street performance, daily driving but no horsepower increase, more torque at the rear wheels. A stock 4v carb starts out on 2v which are smaller than the 2v carb so give better low speed performance and better gas mileage to boot!

Just my opinion headers of all sorts are mainly to impress others in normal driving. Dealer installed duals using the original headers and 2 to 2 1/4 pipes with mellow mufflers give ample flow for low rpm (like under 4000) driving. Port matching of the OEM cast headers helps a little.


Slim

[Klutch]

I really like the advice from Bartl. Boosting the compression to 10:1 is a very good way to get better performance. Yeah, you'll have to run premium gas. But if you add up the total cost difference per year, it's really not that much more money.

I like to run an adjustable valve train. It's really not necessary until you get into the more agressive cam profiles. But I just hate thos positive stop, press-in studs! I don't mind paying to have adjustable, screw-in studs and pushrod guides installed.

Yeah, a stroker kit will indeed bring a big seat-of-the pants improvement. But it can also break a budget. Machinists tend to recommend a stroker kit because they make money selling the kit and preparing the block. But it's purely up to you.

Of course, the choices in cams are endless. I personally like the Ford Hi-Po factory grind. There's a lot of hype out there about all these new, "hot" cams. But the fact is, those guys at Ford knew how to grind a good street cam back then. I also like the classic "rat-a-tat-tat" from solid lifter cams. But that's yet another personal preference thing.

[frdnut]

Lots of good advice in the posts above..If it is a 68 289 it should have the heads with big 63 cc combustion chambers which kill compression..I would swap them for some heads with smaller chambers or go for some aftermarket heads.

[bartl]

Originally Posted by frdnut

Lots of good advice in the posts above..If it is a 68 289 it should have the heads with big 63 cc combustion chambers which kill compression..I would swap them for some heads with smaller chambers or go for some aftermarket heads.

I disagree. I think the '68 heads are better candidates for installation of bigger valves while using the pistons to increase compression.

[tycooley]

a lot of good info. for the record it's a c-code 2v 289 with a c-4. I like the 10:1 ratio so I will start talking to local engine shops.

[ylexot]

Valve spacing remained the same while the cc became larger so I do not understand your comment bartl. I would lose the big cc heads just for 'ease of use' and that 65-67 heads are plentiful. I have 4 sets holding down shelf space myself. Easier to get flat tops and do some home porting than shaving heads, shaving the manifold and getting some pop tops if the shaving isn't enough. 10 from 63cc heads? Advertised was 8.7. Previously 9.3 in 67. You aren't making up a whole point with flat tops. The J code was small chamber and flat tops with an advertised CR of 10.0.

[tycooley]

ok please don't shoot me on this question. What if I put 302 heads on the 289 motor. (I have heard that this has been done in the past)

[Klutch]

Originally Posted by tycooley

ok please don't shoot me on this question. What if I put 302 heads on the 289 motor. (I have heard that this has been done in the past)

No big deal. If you have a set of closed chambered 302 heads, go ahead and bolt them on.

If you wanted to run 351W heads, that would require some mods. As most people will tell you, these days you're better off just going with aftermarket heads rather than messing with 351W heads.

[tycooley]

Will those heads give me a little more power? and what about the exhaust ports?

[bartl]

Originally Posted by ylexot

Valve spacing remained the same while the cc became larger so I do not understand your comment bartl. I would lose the big cc heads just for 'ease of use' and that 65-67 heads are plentiful. I have 4 sets holding down shelf space myself. Easier to get flat tops and do some home porting than shaving heads, shaving the manifold and getting some pop tops if the shaving isn't enough. 10 from 63cc heads? Advertised was 8.7. Previously 9.3 in 67. You aren't making up a whole point with flat tops. The J code was small chamber and flat tops with an advertised CR of 10.0.

Valve spacing is identical, for that matter the heads are almost identical EXCEPT for the combustion chamber. On the early 54.5cc chamber the valves sit right up against the edge of the chamber. On the 63cc chamber the chamber is opened up all the way around the valves. If you were to use the early heads you end up with the intake and exhaust valves shrouded about 1/3 of the distance around and would involve more machine work to cut them back. See the images below:

66 Head


68 Head


Since he's going to be buying pistons ANYWAY, getting some with an 8cc dome over the stockers will bring compression back up and avoid expensive additional machine work on the heads. I also think that the extra room around the valves will aid with flame front propogation and reduce the chances of detonation.

[bartl]

Originally Posted by tycooley

Will those heads give me a little more power? and what about the exhaust ports?

The common late model 5.0HO E7TE heads are 64cc chambers. The valve sizes are 1.78/1.45". The stock '68 head is 1.67/1.45" which is a little bigger on the intake size but still the same restrictive issues on the exhaust side which is where port work really helps. Still the same issues with having to improve compression ratio due to the 10cc larger chambers.

Absolutely nothing wrong with '69-70 351W heads either... 60.4cc chambers with 1.84/1.54" valve sizes, easily upgradable to 1.94/1.60". I guess I'm just not a fan of removing meat from the heads to improve compression if you're replacing pistons to begin with. Depending on how far you go you may be faced with either angle milling or removing meat from the intake sealing side as well. Just call me old fashioned.

351W Head C9/D0


As far as aluminum heads go, you could go with a TW170 with a matching piston which will make GREAT power providing you install a cam that can keep up and the remainder of components are up to the task. You'll be spinning it pretty tight to make the big power numbers at the expense of low end torque though...plus, I'm a cheap SOB, AND I get satisfaction from taking something "ordinary" and improving it, instead of throwing money at the problem.