Main differences between A code and K code

this is what I recall off the top of my head:

Cam: K-code used a solid flat tappet cam for more power and higher RPM capabilities
Heads: K-code heads used more valve spring, screw-in studs and other mods to support the larger cam
Exhaust manifolds: Somewhat better design for better flow
Damper: used a different damper
distributor: dual point distributor, mechanical advance, only
Carb: the K-code used a slightly higher flowing version of the 4100 carb

Unless you want the motor to appear to be a k-code motor, it might be better for you to ask how to make your A-code 289 put out 300 horsepower. Using modern components, this is much easier than it was when the k-code was being built. Is that what you would like?

This won't be a complete list, but some of the differences were hotter camshaft (K), solid lifters (K) vs. hydraulic (A), screw-in rocker studs (K) vs press-in (A), 600cfm Autolite 4100 with manual choke (K) vs 480cfm with heated choke (A). You also had an extra counterbalance (K), crank checked for hardness (K), thicker main caps (K) and 3/8" connecting rod bolts (K) vs 5/16" (A). Exhaust for the K was essentially a cast iron shorty header, but for the A was a log manifold.

With little effort, you can build a 289 motor using updated technology that makes much more than the 271hp the K code made and do so on regular fuel and without breaking the bank. This will be more streetable than the K and not so high-strung. Stroke it to 331 or 347 if you want, or stay with the 289. Go with aluminum or ported, 1.90/1.54 valved 289 or 69 351W heads with upgraded springs, add roller rockers, a more modern performance cam grind and (if you can afford it) roller lifters. On the bottom end and for the heads/intake, ARP stud everything and add a windage tray and double-roller timing chain. Use a RPM or Stealth intake (or Airgap if you only drive the car in the summer). Add a good set of headers and a decent exhaust system. Enjoy. I'm sure others can add to the list, but even in a rebuilt 289 this should get you beyond the 271hp goal you are after.
Daniel

i wonder what kind of power would a set of GT40 heads and a set of good headers would put ya at for horse power.

KaraKedi said:

I would like to put out my A-Code engine horsepower from 225 to ~300. For this, i'm changing some parts in the first step (I already ordered but not install yet)

1) Intake manifold Stealth dual plane
2) Holley 4160 600 cfm carburetor with electric choke
3) MSD Pro-Billet Ready-To-Run Distributors (MSD-8352)
4) MSD Blaster 2 coil
5) Street fire ignition wire set (8 mm)

i'll change headers and camshaft in the second step.

End of the day, does my engine performance up-to 300? If your answer is Not, what can i do for more horsepower.

Regards

Click to expand...

With exhaust (including headers) you'd probably happy with that setup, I would think. The Stealth/Holley combo is a good one. A cam might not be necessary for your purposes.. .the above setup will probably outrun a K-code if the exhaust is done right (SAE Gross... see below). Don't go too big on the exhaust... for your purposes 2.25" pipes, and headers with 1 1/2" primaries might be ideal (generally its easier to find 2.5" pipes and 1 5/8" headers though.. going bigger will hurt your lowend but help a bit in upper rpms).

Also, keep in mind (explaining this gets tiresome, but I feel it must be done)... horsepower was rated differently in 1966 as opposed to today (actually, its changed a couple times... the 60s are even more confusing because manufacturers intentionally fudged ratings for insurance reasons). Without getting much into detail, in the 60s horsepower was rated in SAE Gross units. Now its rated in SAE Net units. The difference has to do with the test method and what accessories are connected to the engine when its tested (i don't remember all the specifics).

Bottom line, its doubtful that a 225 hp 60s Mustang would make the same #'s on a dyno as say... well any 225 hp car today. Its been a while since I've seen a chart, but most stock 289s put down 140-160 rwhp in stock trim, IIRC. This comes out to ~190-200 SAE Net hp at the crank, about 10% (which is roughly the rule, from what some old dude on a Mopar board used to tell me) less than the original rating. This difference starts getting bigger as engines get wilder.

To get to a true, honest 300 hp, you may need a camshaft upgrade. But I'd do the other stuff first and see if you're happy. The stealth/holley/exhaust will give you some growing room if you decide to get more aggressive (all will work well with aftermarket cams and heads if you decide you need it).

(part of me is telling myself that getting into the SAE Net vs. Gross issue might be overkill, but I had it typed out so figured Id might as well)

One thing extra needs to be asked before making recommendations: What kind of fuel are y'all getting in Turkey? Does it have an octane rating on the pump?

Better than we get here: 87/89/93. Actually we have two grades herre, 87 & 93. 89 is a blend of 35% 93 and 65% 87. You've got a pretty good parts list except for the MSD stuff (I'm just not convinced it's worth the money over an electronic conversion of a points distributor & a hot coil, but it's your money) You definately need to do the exhaust to get where you want.

D.Hearne said:

Better than we get here: 87/89/93. Actually we have two grades herre, 87 & 93. 89 is a blend of 35% 93 and 65% 87. You've got a pretty good parts list except for the MSD stuff (I'm just not convinced it's worth the money over an electronic conversion of a points distributor & a hot coil, but it's your money) You definately need to do the exhaust to get where you want.

Click to expand...

87 octane gas is the same as 95 in euroland and 100 octane is the same one as Shell sells in the US as V Power. A matter of some different measuring method.

About the turkey guy, still missing info on his gearing, tires and maybe brakes which I guess are well needed on the classics before adding horses

Given a fixed engine size, your power will ultimately limited by your heads. The intake, cam and exhaust should then match the heads. So, if you plan to make more changes later , especially the cam, then keep this in mind. I would have the heads ported (assuming you will stay with a noon-stroker crank) as soon as you can. The Stealth will be fine. So will the carb you chose. You'll want 1 5/8" headers, though. Then you can pick a bigger cam and not be be disappointed.

This will probably start a discussion on just buying new heads. That, of course is an option. But, personally, I wouldn't do that unless you also stroke the motor. Again, if you think you will stay with the 289, then porting will have good results. You can even ship them to PowerHeads (http://www.powerheads.com) for the porting. They have lots of options, too (valves, studs, etc.). It will cost you as much as some new cylinder heads, but using the stock heads with small chambers will keep your compression up.