Mismatched 289 combo

[b73]

Hi All,

I'm trying to improve a mismatched and under performing 289 combo that's landed in my lap.
I'm looking for suggestions as to the best ways to improve this without re configuring the whole thing.

Basic combo is

289 + 0.030"
Dart Iron Eagle 185cc heads
9.4:1 CR
Comp Hyd roller Adv. 264/270, 212/218 @0.050” , Lift .544/.544 , 112 LSA
Autolite 4100 carb (1.12" 600cfm big block version)
Wieand Stealth intake #8020
Hi-Po cast iron exhaust manifolds, 2-1/4" full exhaust with decent mufflers


It's in a '67 Mustang with C4 trans, 2400rpm stall. 3.00:1 gears (ugghh)

It makes about 180whp on a Mustang dyno where a stock 289 might make 135-150whp.
So its probably making 220-240hp
I know the top end is too big, the cam is small, the gears are tall.
I think some gears would really help as it accelerates okay once it gets moving.
Airspeed in the intact tract is going to be poor.

The tune is good.
I quickly setup the ignition at 20 initial + 16 mech and it's much better down low, but that don't help the top end.

What would you do? Thanks for your input.

[PackardV8]

You've already defined the problem areas and already know the answers; more compression, more cam, more carb, more gear.

[n2omike]

A 3.25 gear is the first thing I'd do. Engine isn't a bad combination. The Hi-Po exhaust manifolds are over rated. Some headers would help. There are some decent mid-length ones out there that fit pretty well, and aren't too much of a pain to deal with. I believe Heddman makes some. The carb is a vacuum secondary, and those rarely ever open very far... and cost a bunch of power. A mechanical secondary carb would help. If you change the gear, a different cam could help wake it up. 4-6 more degrees and a 110 LSA would be nice.

My first changes would be a mechanical secondary carb, mid length headers (as he probably doesn't want to install long tubes) and a 3.25 rear gear... (assuming he doesn't have overdrive, and wants to run 70 mph) A 600-650 double pumper (or modern equivalent) would make it feel a LOT stronger.

These headers look pretty nice. They also have them in plain steel.
https://www.cjponyparts.com/scott-drake ... /p/EXHD77/

I ran this cam back in the day, and it ran GOOD. Lots of midrange!
https://www.summitracing.com/parts/crn-363942/make/ford

But, I'm telling you... A 650 mechanical secondary would be the first mod, then the headers, then the gear, then the cam. I don't think he needs you to build a new engine. All he needs are carb, headers and rear gear.

[Walter R. Malik]

Hi All,

I'm trying to improve a mismatched and under performing 289 combo that's landed in my lap.
I'm looking for suggestions as to the best ways to improve this without re configuring the whole thing.

Basic combo is

289 + 0.030"
Dart Iron Eagle 185cc heads
9.4:1 CR
Comp Hyd roller Adv. 264/270, 212/218 @0.050” , Lift .544/.544 , 112 LSA
Autolite 4100 carb (1.12" 600cfm big block version)
Wieand Stealth intake #8020
Hi-Po cast iron exhaust manifolds, 2-1/4" full exhaust with decent mufflers


It's in a '67 Mustang with C4 trans, 2400rpm stall. 3.00:1 gears (ugghh)

It makes about 180whp on a Mustang dyno where a stock 289 might make 135-150whp.
So its probably making 220-240hp
I know the top end is too big, the cam is small, the gears are tall.
I think some gears would really help as it accelerates okay once it gets moving.
Airspeed in the intact tract is going to be poor.

The tune is good.
I quickly setup the ignition at 20 initial + 16 mech and it's much better down low, but that don't help the top end.

What would you do? Thanks for your input.

What RPM range do you want this to be operated at Wide Open Throttle and how is this to be used 80% of the time...?

[frnkeore]

The things I would do in this order:

Install a AOD with a 4.33 rear. That gives you a 2.96 final and a 10.7 first. That will really lived it up.

Lighter secondary spring.

Headers

230 x 236 @ .050 cam and mill the heads .030 while doing that.

[Walter R. Malik]

Hi All,

I'm trying to improve a mismatched and under performing 289 combo that's landed in my lap.
I'm looking for suggestions as to the best ways to improve this without re configuring the whole thing.

Basic combo is

289 + 0.030"
Dart Iron Eagle 185cc heads
9.4:1 CR
Comp Hyd roller Adv. 264/270, 212/218 @0.050” , Lift .544/.544 , 112 LSA
Autolite 4100 carb (1.12" 600cfm big block version)
Wieand Stealth intake #8020
Hi-Po cast iron exhaust manifolds, 2-1/4" full exhaust with decent mufflers


It's in a '67 Mustang with C4 trans, 2400rpm stall. 3.00:1 gears (ugghh)

It makes about 180whp on a Mustang dyno where a stock 289 might make 135-150whp.
So its probably making 220-240hp
I know the top end is too big, the cam is small, the gears are tall.
I think some gears would really help as it accelerates okay once it gets moving.
Airspeed in the intact tract is going to be poor.

The tune is good.
I quickly setup the ignition at 20 initial + 16 mech and it's much better down low, but that don't help the top end.

What would you do? Thanks for your input.

What RPM range do you want this to be operated at Wide Open Throttle and how is this to be used 80% of the time...?

Judging by your 2,400 RPM stall speed, the cam is a little smallish but,
will work well when using that amount of lift with those heads, if the rest is made right.

That carburetor is hurting this combo very badly.
A Quick Fuel "Hot Rod" series 750 mechanical would be a good fit; especially with a 2 plane intake manifold.
"HR-750" is the Quick Fuel part number and those even have an electric choke.

The intake manifold is probably a little big on a 289; there are several smaller port 2 plane "air-gap" style intake manifolds out in the marketplace...
I have personally had great experience with one of those from a place in Tennessee, I bought new for $189.00 off Ebay.

Headers is a must and mid length OK; no bigger than 1 5/8" primary tubes.

You didn't say your tire diameter but, about 10% increase in rear gear ratio would probably work well; that means about a 3.25/1 ratio.

[falcongeorge]

The things I would do in this order:

Install a AOD with a 4.33 rear. That gives you a 2.96 final and a 10.7 first. That will really lived it up.

Exactly what I was going to say...That and headers and a cam change and you have a whole different car.

[b73]

Thanks for your comments.
I should have mentioned the intended purpose, It's just a street car 6000 rpm max.
I expected someone to say the heads were too big and hurting airspeed but I'm no expert.

I hear you all on the carb and headers.
It has the Autolite and Hi-Po's in an attempt look stock-ish. It's painted black and gold like a stock '65 Mustang motor.

Not really wanting to open it up for a cam swap just yet, but I will do the gears, carb and exhaust and see how that helps.

Thanks again for your comments.

[frnkeore]

I don't think that I'd go to a 750 cfm carb. I think that will hurt the bottom and mid range. Your only pulling 508 cfm, with that 293 CI engine.

The manifold isn't bad but, the Air Gap has just a little bit more mid range but, can loose a little on the top to the Stealth.

The carb you have is a good one. It's 600 cfm but, make sure the secondary's are fully opening. If you switch out the carb, please get back with us, regarding how it works on the dyno and how it preforms, coming off idle or from stall.

Here are some stainless headers, that won't break the bank.

https://www.ebay.com/itm/FOR-63-77-MUST ... SwwlteeHtp

Regarding gearing, here are two examples of the C4 (3.25) vs AOD (4.33). I figure a 1/4 mile trap speed should be in that area.

[n2omike]

Yea, it's just a 289. No need for a 750. A 650 with mechanical secondaries would be perfect.
I think you're on a good path. Carb, exhaust, and gear. If he wants to drive it on the highway, limit that to a 3.25.

As for exhaust, mandrel bends are everything. Flowmaster may still make mandrel bent tailpipes for those cars. They are 2.5", fit great, and were only about $130 10 years ago. The mid length headers linked above are stainless, so they will stay looking good. Lots of guys with these kinds of cars don't want the hassle of full length. 2-1/4" will probably be fine for exhaust, as long as the pipes aren't too contorted. That being said, a typical 'crush' type bender can be brutal when making tail pipes for these cars. Look at what's on it, and see how good/bad they are.

Good Luck

[289nate]

First off, I would be suspicious you don’t have the compression you think you have. What cc chamber head? How thick is the head gasket? Is it truly zero decked or is the piston down in the hole? What piston and do you know the real cc of the valve reliefs? The advertised cc is often much smaller than reality. I had to do some homework when considering shelf parts for my 289 to end up with about a true 10:1 compression. Even ran the pistons .005” above deck. Often people think they have built a 9.5:1 289 and are really closer to 8.5:1. Happened to me on my first 289 build. Keep your power goals in check until you have this figured out.

Next are the hippo exhaust manifolds. They are junk. Only keep them if you are wanting to keep the stock look. Cheap Hooker Comps with a 1 5/8” primary should make more power then mid length headers pretty much across the rpm range. I’ve been running them on my last two 289 builds. Only issue is to be careful going over speed bumps. Then make sure you have a good exhaust system behind them and not some badly crush bent system like Mike mentioned.

That carburetor is also holding you back significantly. Not because of the rated cfm but because of how they function. I used to run a Carter 625cfm AFB on my first low compression 289. Switched to a Holley double pumper (larger cfm than has been mentioned) and the power difference across the rpm range was amazing! And the times at the drag strip backed it up. A 650 dp will be fine. A 750 dp can work especially with the dual plane intake and work well on a future larger more powerful engine. 650 dp if there are no big future plans for it.

Last is something like a 4:11 rear gear and an overdrive transmission. This will instantly significantly increase torque at the tire from the time the wheel starts to turn until you shift, let off the throttle, or stop. The best thing you can do but also the most expensive and labor intensive.

I started with a T5 transmission and a 4:11 rear gear. Then a 4:30 and now a 4:56 as drag racing became more of a priority. Still can cruise it on the highway and drive around on the streets though. 3.25 swap without overdrive will also make a noticeable difference in acceleration while being much cheaper and more simple.

The big problem with a build that falls in your lap is that you don’t really know what you have until you take it apart. Things like the compression issues I mentioned (box said 9.5:1 pistons so that must be what I have). How the cam was degreed in (too advanced or too retarded) can make a big difference. Is the valve train set up properly (correct spring, correct spring height, rocker geometry, pushrod length, etc.).

The obvious issues are what has been mentioned above by me and others. Headers, carburetor, and rear gear. They will also help the heads and intake work (not too big as to make it a turd in my experience and opinion).

What you have makes for a nice cruiser. You’ll just be lacking in potential acceleration.

[falcongeorge]

First off, I would be suspicious you don’t have the compression you think you have. What cc chamber head? How thick is the head gasket? Is it truly zero decked or is the piston down in the hole? What piston and do you know the real cc of the valve reliefs? The advertised cc is often much smaller than reality. I had to do some homework when considering shelf parts for my 289 to end up with about a true 10:1 compression. Even ran the pistons .005” above deck. Often people think they have built a 9.5:1 289 and are really closer to 8.5:1. Happened to me on my first 289 build. Keep your power goals in check until you have this figured out.

Next are the hippo exhaust manifolds. They are junk. Only keep them if you are wanting to keep the stock look. Cheap Hooker Comps with a 1 5/8” primary should make more power then mid length headers pretty much across the rpm range. I’ve been running them on my last two 289 builds. Only issue is to be careful going over speed bumps. Then make sure you have a good exhaust system behind them and not some badly crush bent system like Mike mentioned.

That carburetor is also holding you back significantly. Not because of the rated cfm but because of how they function. I used to run a Carter 625cfm AFB on my first low compression 289. Switched to a Holley double pumper (larger cfm than has been mentioned) and the power difference across the rpm range was amazing! And the times at the drag strip backed it up. A 650 dp will be fine. A 750 dp can work especially with the dual plane intake and work well on a future larger more powerful engine. 650 dp if there are no big future plans for it.

Last is something like a 4:11 rear gear and an overdrive transmission. This will instantly significantly increase torque at the tire from the time the wheel starts to turn until you shift, let off the throttle, or stop. The best thing you can do but also the most expensive and labor intensive.

I started with a T5 transmission and a 4:11 rear gear. Then a 4:30 and now a 4:56 as drag racing became more of a priority. Still can cruise it on the highway and drive around on the streets though. 3.25 swap without overdrive will also make a noticeable difference in acceleration while being much cheaper and more simple.

The big problem with a build that falls in your lap is that you don’t really know what you have until you take it apart. Things like the compression issues I mentioned (box said 9.5:1 pistons so that must be what I have). How the cam was degreed in (too advanced or too retarded) can make a big difference. Is the valve train set up properly (correct spring, correct spring height, rocker geometry, pushrod length, etc.).

The obvious issues are what has been mentioned above by me and others. Headers, carburetor, and rear gear. They will also help the heads and intake work (not too big as to make it a turd in my experience and opinion).

What you have makes for a nice cruiser. You’ll just be lacking in potential acceleration.

Small blocks, overdrive autos and 4 series gears are a match made in heaven. I had a 700R4 with 4.56s and 28" tall tires behind a 355 in my last daily, 200-4r and 4.10s with 26" tall tires in my chevy II. Putting an AOD and 4.10s behind the cleveland in the falcon I am currently working on. These are all real full-time street cars, not "Saturday night specials". Those 80's non-electronic autos are gods gift to hot rodders. I agree with all the comments on the carb too, with a dual plane on a 6000-6500 rpm 289, I would probably use a 4778. Shelby used a 4118 on the early Shelbys, same venturi size on a similar dual plane,on a 289 with a similar power level to what you have, worked well.

[frnkeore]

I have to agree with what 289 says about your compression. I don't have any specs on the Dart heads but, most after market heads are in the 58-64cc range. The early C5-C6 heads, run 53.5-54cc, they get bigger from there out. Deck heights run .016-.011 for stock type pistons. That's 1.6 & 1.605 CH. There are replacement FT's as low as 1.585. Compression is a up hill battle with 289 & 302's. I'm building a high rpm 302, right now, with 54cc chambers, 0.00 deck and 5cc single cut pistons and can only manage 10.4, at best. It's a lot of work and costs quite a bit, to get compression on a 289/302 and you have to know your numbers.

On the chart I'm posting, I'm using 58cc heads and the head gasket is 8.87cc (4.1x.041), More common is 9.1cc and a standard .016 deck. I used 7cc for a double cut piston. That is best you can do, it will be more like 8-10cc and you have to add in the area between the top of the piston and first ring, that adds 1-1.5cc.

You can't compare a AFB to a Ford carb. The Ford will give the same as a 600cfm 1850, maybe more but, as on all VS carbs, make sure the secondary's open. It only takes a spring. In 1969, I held the HPS record, with a smaller version of that carb, in my factory, '64 Fairlane, 271 HP, 289.

For the price of a new 650 DP, you can buy a used AOD & 4.33 gear set. The labor is the same for the gears but, more to install the trans, than a carb.

[n2omike]

Small blocks, overdrive autos and 4 series gears are a match made in heaven.

Just depends on the combo and its intended use. The engine currently has a cam that is 212 @ 0.050", and is low compression. It's going to make good low and midrange power, while being all finished by 5500-5800 rpm. With a hotter engine, the 4.xx gear would be great. With this one, a 3.55 will feel like a 4.11 in those cars.

I've had my 1966 mustang since age 15. (52 now) It spent many years as primary transportation. It has gone through numerous engine/trans combos. It started life as a worn out 289 2bbl with an auto trans and 2.80 rear.

I have had, and street driven the following gears in the car... 2-lane as well as interstate. With 'mustang' sized tires and cruising up to around 70 mph with no overdrive, the 3.25 is about the ideal compromise between power and cruising speed. This is coming from direct experience with 289-302 engines in mustangs. I've run 2.80, 3.00, 3.25, 3.40, 3.50, 3.55, 3.70, 3.89, 4.11, 4.30, 4.33, 4.56 and 4.86 in the car. Some were with an 8", some after upgrading to a 9". 3.55 is great around town, but buzzes a bit too hard with mustang sized tires at speed. 4.11 feels like driving a tractor down the interstate if you don't have overdrive.

IF you can get an overdrive, go for the steeper gears. If not... especially with a low-end, mid-range engine... I'd be hesitant to go steeper than 3.25.

Engine could use more compression, but for the small cam... it will probably be fine.
Carb, exhaust and gear would be first. As for headers, long tubes can be a PITA. Shorter mid-length are 90% as good, and are generally a lot less hassle. If you want to delve into an overdrive, study up to see if the trans tunnel will need cut for an AOD. I don't know. You'll need one without electronic control. I put a 1986 TH 700 R4 in a GM vehicle. It had an electronic lockup converter, but the transmission rebuilder did away with the electronic lock-up. Maybe the AOD can be done the same way if you go that route. Personally, I'd convert to a T5 5-speed if I were going to do any trans swaps.

Good Luck

[frnkeore]

AOD's hook up, the same as C4's, no electrics involved. They are longer though.