Ford noob question - 289 or 302 - how to tell?

[serial car restorer]

So please bear with me here, my '69 Bronco is the first Ford I've owned since high school in the '70s. When I bought the Bronc, the seller told me he didn't think the engine was original (based on comments from the family he bought it from 12 years prior), and didn't know if the engine in it now is an early 302 or a late 289. How can I determine which I have, short of pulling a cylinder head to measure the stroke accurately? Any external clues?

 

[1969]

I believe above the starter is a cast number for the block. You could post the numbers and someone will be able to tell based on those.

 

[Broncobowsher]

For the most part, you can't tell the difference. There are clues that hint one direction or the other. Casting dates of the block are one of them, but that doesn't mean what is inside matches. About that time there was 302 cast into the lifter valley of engines filled with 289 guts (or was it the other way around?).

Next, what does it matter? So long as it is running good, leave it alone. Need minor work, minor parts are the same. Overhaul, find out when you get it apart.

 

[serial car restorer]

That's what the seller told me—external indicators are not reliable for this. It appears that I'd need to pull a head to be sure.

And it's not purely curiosity. The engine runs pretty good, and seems healthy other than a totally borked carb. I could just slap on a new carb and call it a day, but I'd like to go EFI on this build, and have been leaning towards the Howell TBI system. Since the Howell is not self learning, and Howell's tune for 289 and 302 are different I'd like to be sure which I have. I doubt I can measure the difference between 3.9" and 4" stroke using a dowel through a spark plug hole. Not a good, straight shot.

 

[Broncobowsher]

289 is a 2.87" stroke
302 is a 3.00" stroke.
4" stroke is for a 400, or typical stroker kit for a 351 with a little overbore gets you a 408.

If you pull a head just to see, you will be opening a can of worms. Don't do it. Didn't know Howell was still in business. Talk to them about it, I bet they will offer a software solution. All else, the 302 tune might be a little rich on cold start but once in closed loop will self correct. Many years ago I watched a "good running" Howell EFI go on the dyno. The tune was far from perfect. Closed loop it drove great. Started right up, all the normal good EFI things. But open loop was off the charts. If you are going old school like that, I would say to just get a Q-jet and be done.

 

[bmc69]

I doubt I can measure the difference between 3.9" and 4" stroke using a dowel through a spark plug hole. Not a good, straight shot.

2.87" versus 3"..and yep, pretty difficult to measure such a small difference through the plug hole.

The last 289 block casting number was C6AE-C. The first 302 block castings were C8OE-A and C8TE-B.

 

[phred]

I’ve messed with Howell systems and as stated closed loop they perform well but are difficult to get to that point. We had several chips custom burned in an effort to get the idle clean and the odd surge between shifts to go away. Eventually it was replaced with a self learning system. In a stock application I would recommend going with a qjet built by Jet performance or someone like them. I’ve had a qjet on my truck for over 10 years. It starts and drives great. I have not touched it since I installed it and set the mixture.

 

[Quick & Dirty]

Dropping the oil pan should be easier than pulling the head. A factory crank will have an ID stamped/cast in one of the counterweights.
1M, 1MA = 289 (28 oz-in)
2M, 2MA = 302 (28 oz-in)
2MAE = 5.0 (50 oz-in)
If it's an aftermarket/stroker crank you'll need to dig deeper.

 

[serial car restorer]

Dropping the oil pan should be easier than pulling the head. A factory crank will have an ID stamped/cast in one of the counterweights.
1M, 1MA = 289 (28 oz-in)
2M, 2MA = 302 (28 oz-in)
2MAE = 5.0 (50 oz-in)
If it's an aftermarket/stroker crank you'll need to dig deeper.

Great tip! I'm likely to drop the pan anyway to replace seals and gaskets, so this is no extra work.

Also, good info on the drawbacks of the Howell system, thanks to all. I like the idea of OEM quality parts, but the drawbacks of not being self-learning are significant. I'll give the other options (including staying with a carb) some more thought.

 

[ared77]

^^^^All of that is great advice. You can also use link below to see what it says about the casting numbers off block, heads, crank, etc if you are just curious.

Ford casting ID numbers and part identification info for Mustang Shelby parts

Ford and Mustang casting identification. Find detail pictures and information for parts identification. Classic 60's early 70's Mustang, Shelby, Boss and Ford casting ID numbers. Covering 260, 289, 302, 351, 352, 390, 406, 410, 427, 428 and 429 engines. Details ID identification and pictures of...

www.mustangtek.com