289 vs 302 block

[markw]

Sad tale but true. Prepared to start my newly rebuilt 289 on test stand yesterday. Filled the radiator and heard water pouring into the pan. Drained pan, out came a gallon of water. Pulled pan and fond a 1/2" hole in the bottom of the water jacket #3 cylinder. Took pics, sent to the builder who came over and confirmed rust through. After all the "how the f did I miss that?" was finished it was time to plan a new build. Yes, hes's taking care of it but I need to find a new block. Where do I find a first run 289 block? Can I substitute a 302 block? Flat tappet cam and all that. Suppose I can ditch my new cam for a roller but would rather not. Builder is on the hook for finding a block but I want to know what my options are. Thanks in advance! Mark

 

[Timmy390]

All parts will interchange except the crank,rods,pistons. Those have to be either all 289 or all 302 due to slightly longer stroke of 302.

I would go to the yard and get a complete Explorer engine. Roller cam, one piece rear main seal, GT40P heads, intakes for future EFI, and Explorer front dress. Can get them for $350-$400 around here. 99% are int eh yards due to wrecks and were running when smashed. I just pulled some GT40P heads off a 2001 Mountianeer with 144K on them and they were clean and it appeared to have had reg oil changes.

Or just put the 289 parts you have on the Explorer block.

Tim

 

[Broncobowsher]

289 block is the same as a 302.
There is something different with the back of the crank when going to a 1-piece rear main seal. Forget what the differences are.

Having driven both 302 and 289 I feel the 289 is a better running engine and could never notice any difference in power.

Since the builder is doing good, no need to screw him over and get a late 5.0 block that will work but isn't as direct of a replacment as an older 302 block.

Yes, a 302 block will work. Talk with your builder about which one he would like to use. rebuildable early blocks are getting harder to find simply by attrition.

 

[Timmy390]

Having driven both 302 and 289 I feel the 289 is a better running engine and could never notice any difference in power.

The rev quicker due to the shorter stroke........Boss 302 and 289 rods are the same length.....

Tim

 

[markw]

The builder is a friend of mine for 20 years and a stand up person. Just made a mistake.
I may have a usable 289 block. Need to check the bore, I don't want more than 40 over, I've heard of overheating problems. Also have a line on a complete 289 and 302 block. Thanks for all the help and replies. It's why I'm on here every day! Mark

 

[Timmy390]

Going 40 over or more is block specific. Some can some can't etc. My 390FE is 40 over and no overheating at all but it's not going any bigger as the block can't take it.

You could always get the block sleeved.

Tim

 

[DaveLev]

Sleeving a block is expensive. I would not do a 60 over 289 or 302 given the bronco's propensity to overheat. But as your builder - the stand up guy that he is - is the one doing the build, you should let him know this preference soon before he does get you a 60 over block. He's probably trying to find something that uses the same size pistons that he already bought.

 

[markw]

Hi Dave That's the concern. We had a first run block with 30 over and that will be hard to duplicate. If he has to replace the pistons and rebalance everything so be it. I haven't paid him anything yet so I have some leverage. Hope it doesn't come to that though.

 

[Rustytruck]

I would run a want ad here.

https://californiafords.com/cgi-bin/ultimatebb.cgi?ubb=forum;f=5

 

[markw]

Thanks Rusty, I'll do that if these other leads don't work out.

 

[ntsqd]

There is a slight difference btwn the 289 and 302 blocks according to the Ganahl book, but I doubt that the slight increase in cylinder bore length will be an issue. oh, and one says "289" in the lifter valley while the other says.....

Anything over .030" over I'd give serious thought to sonic checking an SBF block's wall thickness. They mean it when they call these "thin wall castings".

 

[El Kabong]

As you might be looking for an old block be aware that the very earliest 289 blocks had 5 bellhousing bolts. Like in late 64 early 65. After that 289s went to 6 bolts, & continued with 6 for 302s.

 

[markw]

We've come across all of these things in our search. The core I have is a 302 per the casting in the valley. Looks like original pistons though one is in about a dozen pieces. Not sure what grenaded that but I hope it didn't destroy the block. Taking it to the builder today.

 

[tirewater]

Do you mind posting pictures of the hole in the water jacket?

 

[markw]

I'll get a picture up this evening. In the meantime the 302 block is bad as well. The broken piston broke out the piston skirt. However, I found a 1971 302 block casting D1ZM apparently a Mexican block. Also ordered a Ford Motorsports single plane intake manifold. I've read they work better than dual plane with FITech FI. Had a Weiand on it for the square bore as I was going to use a Quadrajet carb. This is just one reason it's taking so long to get this project done. Better stuff keeps coming along.

 

[Timmy390]

I'm not sure about the FiTech but there have been several threads about other TB EFI's not working well with a dual as the MAP sensor can't read the air on both sides of the plane. The trick is the "notch" the plane so the MAP can read the air coming in correctly.

Maybe FiTech is different but lots of info on using a single plane for the Holley Terminator.

Tim

 

[markw]

#3 cylinder water jacket rust through.

 

[markw]

Maybe this went through

 

[DirtDonk]

Also ordered a Ford Motorsports single plane intake manifold. I've read they work better than dual plane with FITech FI.

Nothing wrong with that. But as Timmy said, the FiTech unit is not as finicky with divided plenums as other throttle body setups seem to be.
Still, doesn't hurt to open things up a bit most likely. Interested to hear how it all turns out.

Paul

 

[markw]

I'm hoping to get this thing back in 4-6 weeks. We'll start it up on the stand then take it to the dyno to tune and get some numbers. I won't have anything to compare it with but it will be interesting to see how it does.