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Havoc65,

I’m going on 42 years of marriage with my charming bride.
Primary lesson in all that time, better to ask for forgiveness then for permission hands down.
Guys can I get an Amen?

I tend to maximize efficiencies when building a motor.
That said, if the ridges you noted at the top of your cylinders when you changed the head gaskets were deep enough to reguire boring I would suggest you take a step back and consider what your long term goals are. Given you are already at .40 over, would .60 take away all taper leave enough material for honing. Keep in mind not all factory 289 blocks were created equal. Some handle .60 better than others.

So if you have to buy a new set of pistons why not sleeve your block, 400 to 500 bucks, and pick up a standard set of pistons. That way if you decide to add so power down the road your foundation is able to handle it.

Just my .02.

Good luck whichever way you choose.
 

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My opinion, bore it 60 and pressure test the block. Sonic test wouldn’t hurt either. If you have a leaky hole sleeve that one. I think I would likely consider moving up to a tree fiddy one instead of rebuilding a 289. Sure, they have their charm, but so do the extra cubes. Anymore I would consider a modern FI motor, as they make so much more power.
 

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Discussion Starter #26
Doesn't help much IMO. Hard to tell anything about a photo, especially one 18 months ago. The measurements from a mic would help...

How many miles since that picture? (Not that it really matters.)

Allen
Hard to say on the miles since my odometer doesn’t work but probably only a couple thousand at the most. Weekend cruising mostly.
 

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Hard to say on the miles since my odometer doesn’t work but probably only a couple thousand at the most. Weekend cruising mostly.
Roger that. I recall you said it doesn't smoke. You may get away with a "refresh". It's getting late, I'll have to look back on the intentions. I love a 289 screaming at 7k rpm, probably not what you're looking for but if you want to keep it, you can certainly make it work (provided the walls are thick enough to handle the over bore).

Allen
 

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The weak link in the bottom end of a stock 289 is the 5/16” rod bolts. That said a carefully prepped 289 can readily produce 350hp all day long. If that fits your bill, I’d suggest your machince shop help you decide what you have and get their opinions as to what your options are and the relative cost for each. Their having your block in hand would best of course.
Then choose path right for you and pick up some flowers for your sweetie on the way home😉.
 

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My advice, and it's only worth what you paid for it... :D
  1. Check your valve seals first of all. If you have the stock style umbrella valve stem seals, they're notorious for leaking, and breaking down, cracking and altogether failing. These will make a perfectly good engine smoke like a tired half-a-million-mile clunker!
  2. Have your engine builder measure your bores - and are they square? You may not need to punch it out any further. It'd be great if you could get by with merely a hone and new rings. And a ridge reamer can remove the ridge without boring.
  3. Camshaft selection if rebuilding... Lots of recommendations on this forum for the C9OZ-6250-C cam as a nice solid street performer with excellent driveability. I have the M-6250-A312 cam (very similar specs) which is a great all around performer. A Ford Motorsport engineer recommended the A312 cam because in California we're stuck with crappy unleaded fuel, and the split duration favoring the exhaust side would be a better choice because it supposedly makes more power with our unleaded gas.
    1. C9OZ-6250-C - single pattern cam; Duration @ 0.050: 218°; Lift: .470"
    2. M-6250-A312 - daul pattern cam; Duration @ 0.050: 214°i / 224°e; Lift: .472 i / .496 e
Whatever you do, keep us posted.
 

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I slammed in a junkyard GT40P. Paid $450 for it. Sold off the EFI parts for $175. Then bought a used Wieand Stealth intake, USA made too for $80, used 91 Mustang 5.0 cam $60, used Edelbrock 600 $125. I did pony up for a good set of .540" valve springs, shims and seal, about $200. This cheap pile of parts runs very, very well!
741094
 

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Discussion Starter #31
I slammed in a junkyard GT40P. Paid $450 for it. Sold off the EFI parts for $175. Then bought a used Wieand Stealth intake, USA made too for $80, used 91 Mustang 5.0 cam $60, used Edelbrock 600 $125. I did pony up for a good set of .540" valve springs, shims and seal, about $200. This cheap pile of parts runs very, very well! View attachment 741094
Nice! What headers did you use? I’ve thought about getting a P motor header issues kinda scare me away. I’m using a z bar clutch too
 

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Off the shelf MAC longtubes. I did a write up a couple years ago on my swap. Unfortunately this recent VFM format "upgrade" lost a lot of pictures and no edit button

I'm using a Z bar adapter bracket
 

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Discussion Starter #33
Off the shelf MAC longtubes. I did a write up a couple years ago on my swap. Unfortunately this recent VFM format "upgrade" lost a lot of pictures and no edit button

I'm using a Z bar adapter bracket
Any idea if they’d clear a Borgeson steering box? Might be an option for me.
 

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This was from a thread I have about headers borgeson, and zbar clutch linkage:

MAC headers claim to fit with stock power steering and Z bar. While I dont have a Z bar, I do have Borgeson power steering and they clear the box just fine. They have good ground clearance too. As a matter of fact, they make an entire 2 1/2" exhaust that fits fantastic in my opinion.
 

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Discussion Starter #36
I spoke to a couple of machine shops today and they all were confident they could rebuild the motor. With that in mind any cam recommendations? I have an edelbrock rv cam in it now which was ok but with the T5 and 3.80 gears I have now I think something a little more rev happy would be better.
 

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See post #29 above... The Motorsport M-6250-A312 is a great all-around street cam. It idles well with mild lope (ever so slight IMO). Great around town driveability and really comes alive when putting your foot into it or on the highway.
 

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Discussion Starter #40
See post #29 above... The Motorsport M-6250-A312 is a great all-around street cam. It idles well with mild lope (ever so slight IMO). Great around town driveability and really comes alive when putting your foot into it or on the highway.
Thanks! I missed that.
 
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