Need help with a motor rebuild

[Ptaylor459]

Hey everyone, it's my first time posting on this forum, been on LS1Tech for a while for my 98 T/A. I have a few questions regarding my 66 Mustang coupe, however. I rebuilt the car with my dad about 3 years ago ( Mostly body work, brakes, and suspension work) and we left the motor and transmission as they were, which is stock i suppose. The 289 in the car currently is not numbers matching, but still runs strong. I've been wanting to do a motor rebuild in the car for some time but didnt know where to begin. I've heard you can stroke a 289 to a 347 but it reduces the lifetime of the motor severely and that is something i do not want to happen. i want a motor that gets 5-8 mpg when hotroding around town and has a decent amount of power. I also didnt know if a 302 block could fit in the car without modifying the shock towers, because a 302 can defnitly handle a larger crank in it than a 289, thus producing more power ( which is good). I want to stay as cheap as possible but still produce adequate power. Should i go with a 302 block from CJ pony and get a forged crank/stroker kit for that motor and get matching heads/cam and build it from there up? Im pretty lost about where to even begin with this process so help is greatly appreciated.

Thanks,

Patrick

[theman1990]

I think the 302 and 289 blocks are same size but either way, the 302 or even 351W will fit. The words "cheap" and "performance engine" don't get real close but you can get into a 347 for 4-6K w/ decent parts. The "lifetime issue" of 347's is no longer the case w/ newer 347 kits w/ improved piston ring and geometry. Search in the modified section for more answers...

[Nickm1024]

In building engines, they always say you can have any two of the following, but not all three

Cheap
Reliable
Fast

[22GT]

I've heard you can stroke a 289 to a 347 but it reduces the lifetime of the motor severely and that is something i do not want to happen.
There's always a tradeoff.

i want a motor that gets 5-8 mpg when hotroding around town and has a decent amount of power.
Pretty low standards. You can get to 320 hp and still get 15 mpg.

I also didnt know if a 302 block could fit in the car without modifying the shock towers, because a 302 can defnitly handle a larger crank in it than a 289, thus producing more power ( which is good).
Someone has totally mis-informed you. The 289 and 302 blocks are entirely identical, inside and out, except the cylinder skirts of the 302 block extend downward an additional 1/8". Any stroker kit will fit either block.

I want to stay as cheap as possible but still produce adequate power.
OK, no problem.

Should i go with a 302 block from CJ pony and get a forged crank/stroker kit for that motor and get matching heads/cam and build it from there up?
I thought you had a budget. What you now describe is literally throwing money at the project.

I'm pretty lost about where to even begin with this process so help is greatly appreciated.
Here’s the system for an inexpensive 289/302 build:

• At the heart of any build, the camshaft. The C9OZ-6250-C was Ford’s hydraulic version of the 289HP cam. It offers excellent driveability, and good power through 5000+.
• Screw-in rocker studs. Cheap, and will add reliability to your upgraded valve system.
• Edelbrock Performer RPM or Cobra intake manifold, and 600 cfm carburetor.
• 289HP air cleaner.
• Cylinder heads port-matched to the exhaust manifolds (289HP) or headers.
• Stock distributor curved to BOSS 302 specifications.
• Flat-top pistons.

This simple formula has been dyno tested at 323.5 hp @ 5300 rpm, and can be done for under $1000.

For increased power, at the price of increased maintenance, you can use the C30Z-6250-C 289HP mechanical camshaft, or more significant increase with the Cobra LeMans C7FE-6250-A mechanical camshaft. Ford reported over 350 hp with the C7FE-A, although their figure includes 351 heads with oversize valves.

Notice in particular that this does not specify exotic ignition, fat plug wires, or a bunch of chrome. None of that will significantly improve performance, so is not included. Such things are useful for impressing people with the size of your wallet at cruise night, though.

[Ptaylor459]

Like i said, im new to modifying motors and essentially the whole pricess of rebuilding so I'm sorry that some of the things I had said previously were not 100% accurate.

Moving foreword, I've been looking at getting a 302 block ( from an older ford such as 89-93 mustangs i believe) and building it from the block up. I dont want to spend too much money on the rebuild, but i do want to achieve at least 325-350 rwhp. and get decent gas mileage at the same time. I know these 3 are contridictory but I want the best combination of the 3. Not breaking my wallet, making good power, and good drivability.

As for the help with the cam, thank you for that. It helps point me in a better direction for where to start. Where did you gain knowledge on rebuilds? Im in the dark essentially with cam times/durations and matching heads with a cam. SO my question is, where do i begin with that process?

[PairOf66's]

Unless your planning on using a roller camshaft (which you can still do with correct lifters) why would you want to buy a 302 block when you already have a 289? As 22GT stated they are the same block.

[Ptaylor459]

Because I've heard from multiple places that turning a 289 into a 347 causes the motor to have a lot less of a lifespan. Turning a 302 into a 347 has more of a lifespan apparently

[22GT]

Moving forward, I've been looking at getting a 302 block ( from an older ford such as 89-93 mustangs i believe) and building it from the block up. I dont want to spend too much money on the rebuild…
Why not just use the 289 you already have?

…but i do want to achieve at least 325-350 rwhp. and get decent gas mileage at the same time. I know these 3 are contradictory but I want the best combination of the 3. Not breaking my wallet, making good power, and good driveability.
The 289HP with the C3OZ-6250-C cam gets 14-18 mpg, and idles smoothly.

As for the help with the cam, thank you for that. It helps point me in a better direction for where to start. Where did you gain knowledge on rebuilds?
Decades of blundering.

I'm in the dark essentially with cam times/durations and matching heads with a cam. SO my question is, where do i begin with that process?
Here. Heck, the formula I gave you above will get you to 320 hp. You might do better, but not without spending oodles of cash. Why do you want to spend money on heads so badly, for example?

[dobrostang]

Originally Posted by 22GT

I've heard you can stroke a 289 to a 347 but it reduces the lifetime of the motor severely and that is something i do not want to happen.
There's always a tradeoff.

i want a motor that gets 5-8 mpg when hotroding around town and has a decent amount of power.
Pretty low standards. You can get to 320 hp and still get 15 mpg.

I also didnt know if a 302 block could fit in the car without modifying the shock towers, because a 302 can defnitly handle a larger crank in it than a 289, thus producing more power ( which is good).
Someone has totally mis-informed you. The 289 and 302 blocks are entirely identical, inside and out, except the cylinder skirts of the 302 block extend downward an additional 1/8". Any stroker kit will fit either block.

I want to stay as cheap as possible but still produce adequate power.
OK, no problem.

Should i go with a 302 block from CJ pony and get a forged crank/stroker kit for that motor and get matching heads/cam and build it from there up?
I thought you had a budget. What you now describe is literally throwing money at the project.

I'm pretty lost about where to even begin with this process so help is greatly appreciated.
Here’s the system for an inexpensive 289/302 build:

• At the heart of any build, the camshaft. The C9OZ-6250-C was Ford’s hydraulic version of the 289HP cam. It offers excellent driveability, and good power through 5000+.
• Screw-in rocker studs. Cheap, and will add reliability to your upgraded valve system.
• Edelbrock Performer RPM or Cobra intake manifold, and 600 cfm carburetor.
• 289HP air cleaner.
• Cylinder heads port-matched to the exhaust manifolds (289HP) or headers.
• Stock distributor curved to BOSS 302 specifications.
• Flat-top pistons.

This simple formula has been dyno tested at 323.5 hp @ 5300 rpm, and can be done for under $1000.

For increased power, at the price of increased maintenance, you can use the C30Z-6250-C 289HP mechanical camshaft, or more significant increase with the Cobra LeMans C7FE-6250-A mechanical camshaft. Ford reported over 350 hp with the C7FE-A, although their figure includes 351 heads with oversize valves.

Notice in particular that this does not specify exotic ignition, fat plug wires, or a bunch of chrome. None of that will significantly improve performance, so is not included. Such things are useful for impressing people with the size of your wallet at cruise night, though.

+1 on everything above especially the comment about the chrome! Everyone here on this blog knows that if you want big HP on a Ford go beadblasted aluminum Cobra valve covers, air cleaner etc... - Gratuitous chrome only works on Chevys although there are a few hold-outs that swear by chrome export braces, go figure...

M

[bartl]

Originally Posted by Ptaylor459

Because I've heard from multiple places that turning a 289 into a 347 causes the motor to have a lot less of a lifespan. Turning a 302 into a 347 has more of a lifespan apparently

Positively not true. The older 289 and 302 blocks have more "meat" in the main webbing area and will hold up better than the 5.0, which does have a higher nickel content which makes it more resistant to cylinder bore wear. The best block would be a "Mexican 302" which are also high nickel blocks but incorporate heavy duty (almost HiPo-like) main caps, although you can now purchase reproduction HiPo main caps. Everything that 22GT said is spot on, and if you feel even more ambitious you could rebuild those stock heads with bigger valves (1.94"/1.60") and do some more aggressive porting to really make them breathe.

The "older" 347 strokers used a piston that put the wrist pin hole up in the oil ring area and these experienced some oil consumption issues. Now, pistons are available that avoid this issue. As far as reliability is concerned, the biggest factor is piston speed, especially at both ends of the stroke with the short rods. Using a cam that makes its peak power below 6,000rpm will help longevity.

Just bear in mind that torque is what gives you that "pressed into the seat" feeling. It's one of the reasons why you see folks building 351W-based strokers of 393, 408 and even 427ci displacements.... that 4" plus stroke computes to "grunt"...and, yes, a 351W block WILL fit in a '65-66 chassis with swap headers. It's a "snug" fit but definitely do-able.

[Ptaylor459]

Thanks for all the help guys.

So, barti, you're telling me
That a 351W will fit with swap headers? What does swap headers mean? Swapped from stock? As in TrI-Y or something similar? Also isn't the deck height of a 351W higher than a 289? I have a really nice metallic pain job with racing stripes on the car currently and I wouldn't want to have to buy a new good for my motor to fit

[bartl]

The "swap headers" are designed to fit a 351W when installed in an early chassis so that they avoid the shock towers, steering box, etc. You can find them from Accufab, Hedman (shorty), Hooker, Sanderson (shorty), etc.

Yes, the 351W deck height is 9.5" as opposed to the 289/302's 8.2", but remember, since it's a 90* V8 that only equates to an increased width of about 5/8" per side. You just want to make sure you lay something protective on your engine compartment paint. From a height perspective, a drop-base air filter and thinner spacer will probably be needed but it will fit under a stock hood.

[PairOf66's]

Here are my Hedman Shorty 351W swap headers. It is a tight fit as you can see where the shock towers indented the headers due to weak motor mounts. I run a 3-in air cleaner with 1-in. drop and have no hood clearance issues.