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My 302

10K views 158 replies 11 participants last post by  OklahomaCoupe 
#1 ·
I picked up a used 95% complete 302 that ran but needs a rebuild for $150. I tore it down last night and everything looks pretty clean and the crank turns smooth. I measured the bore and it measures 4.00" and according to the web thats what a 302 should be.

All I'm really wanting to do in the rebuild is add a mild cam, 4 barrel intake and carb, and headers(mainly because of budget). My car is going to be a cruiser so I would like to get around 300 horse power is possible.

What are the major steps that I need to do in the rebuild process?
 
#3 ·
To do it right you need to take it to the machine shop. They will bore the cylinders .020 or .030 over stock and hone them. They should also line bore the bearing surfaces and size the piston rods. Depending on condition, they may also need to grind the crank shaft. Then you (or they) install new bearings and oversized pistons and whatever cam you choose. All that (not including parts) should not cost more than a few hundred dollars. Once done, however, the motor should be good as new.

Are you going to replace the heads? It may be hard to hit 300 HP without addressing the heads.

Baxter
 
#4 ·
Most of the early stock 302's had either 210 or 230 horsepower. The difference was whether they had two or 4 barrel intake/carb setup. If you want to keep most of it stock, have it bored .030 over, go with a set of pistons that give about 9.0 to 9.5 compression. You might be able to go as high as 10.1. Wouldn't go too high, or running on pump gas gets iffy. A more aggressive roller tappet cam/ lifters. Flat tappet ones rob horsepower and have too many issues these days. I've had good luck with Lunati cams, stay away from Comp cams, seen too many on Fords and Chevys that literally melt. Also get a free breathing Exaust like Flow master, Magnaflow, Borla. On the Exaust run a h pipe and good flowing headers. A good friend installed an h pipe on his small block Chevy, and loved the difference it made. Better low end, midrange power. Of course run a good breathing K&N filter. A large carb mounted ones are my favorite. The cone ones give more top end, but you need to run out in the fender, and lose low end torque. Well that's what I would do, hope that helps.


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#8 ·
Any interest in selling the 289? With the right date code, a decent running 289 could be worth something to anyone trying to restore a car. Might be a way to pick up some of the cash you need to build that 302 the way you want it.
 
#15 · (Edited)
My thoughts my engine builder gave me for general evaluation:
When sorting thru what's good, what's not for a common small block: General if done by a prof and don't wanna be second guessing "if this if that" is in spec, it all can cost money to check. And once you start going thru engine eval process, where do you draw the line when some parts "marginal", replace others?
IF you don't do the engine work yourself (meaning assembly after machine work), my engine builder told me cost wise, cheaper to buy a short block crate engine, comes with a nice warranty?
I'm about doing thing right the first time and the engine is the heart of the car.
If you rebuild an engine (freshen it up" and it fails or smokes later, gotta start over.

But if you're certain just needs a few simple things, low mileage, then move forward with it.
Also newer 302's (not sure what years) the firing order is different than the classic 302. Others can answer that.
 
#16 ·
Hydraulic Roller

Will manifold vacuum be a consideration in your cam decision (now, or anytime in the future)? "Cruiser" is a term that means a different thing to different people. Will your cruiser be equipped with P/S, P/B or air? These are all thing that will factor into your build decisions, if you don't want to be forking out more cash to redo things down the road. Believe me, I speak from experience!
 
#18 · (Edited)
That engine will be the same 28 oz balance and will have the boss on the side of the block for the clutch equalizer ball stud if you have a manual transmission and use the stock clutch linkage. The heads are junk. They have have 69 CC chambers and very poor exhaust ports. You can pick up used GT40 heads pretty cheap. They'll be a huge difference over the stock heads. If the cylinder walls still have the cross hatching they'll probably not need boring. Best thing is to have a shop check the block out. I would go with either a hydraulic flat tappet or roller cam. There really won't be any difference in performance on a street motor. Experts say you needed around 280° advertised duration before you see an advantage in the roller design.

I was sort of in this spot a while ago with a fresh reman 302 around the same year along with a set of new GT40P heads. I thought about my actual plans, use and budget. The more I thought about it the more it made sense to change paths on my build and buy a used 97 Explorer GT40P motor. I sold my GT40P heads for $525 and bought the whole motor for $450. I needed new flywheel and balancer no matter which engine balance I went with, so that was a wash there. If anything it saved me money as my brother gave me a Mustang 5.0 clutch kit a long time ago. While new hydraulic roller cams are not cheap, used ones are and there are a lot of them out there. You do not have to match the tappets to the lobe or breAk them in. You simply swap the cam and reuse your old roller tappets. I bought a used 91 Mustang 5.0 cam which is slightly hotter for $60 used. There are a lot of good used roller cam motor parts out there cheap.

Here's a link to my build. I'm not saying you should or need to copy my build but rather to think exactly what you want to do, keep your options open and look outside the box to get to your goal.

http://forums.vintage-mustang.com/v...t-my-gt40p-up-running-my-66-a.html?highlight=
 
#27 ·
No, what I'm saying that worked for me. Lay out exactly what your long term plan is and what's the best way to get there. While I had a fresh motor I wasn't stuck on having a fresh motor. These roller cam motors will go for 200K miles no problem is taken car of.

I will say it runs very, very well for a cheap stock type motor. It runs a lot better then my expectations. It idles nice, lots of torque and revs very easily.
 
#20 ·
Your power brakes will require manifold vacuum to operate, unless you intend to go with a hydro-boost setup. As cams get more aggressive, vacuum generally goes down, often to a level that does not meet the manufacturers minimum spec. This is why you have to prioritize your wants and needs! Some of what you loose in being forced to use a mild cam can be made up elsewhere.
 
#30 ·
I did a little more research and found that Ford didn't use a 5.0 in their mustangs in 80,81. They did in 79, then again. In 82. In 80,81 they used a 4.2. That said your motor if in fact is 1980, probably came out of a truck, or passenger car. Problem is it's probably no more than 160 horsepower stock. You've got a long way to go to make that motor if you use it, to put out anywhere near 300 horsepower. It can be done, but your talking heads, boring, stroking motor, cam. I guess at this point tear it down, if internal block isn't damaged, have block magnafluxed to check for cracks, and build up. I tend to side with the other guys, and buy a quality rebuild. Summit has a pretty good rep. I've had friends but motors from them for Chevys with good results. They have a 300 hp engine for $3600.00, good to go.


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#35 ·
302 build

OKCoupe, can you give us some casting numbers ? Yes, you can easily hit arond 300 hp with a 302, and you can even use your factory heads. If you get a good deal on GT40s or 351W heads thats great, but the stock heads will work if your budget is limited. The bigger intake valves from a 351W can fit into the 302 head and help you a bunch. But first we need to know if you block has to be bored or not, and then choose some pistons. Most guys unintentionally get pistons that are too short. Let us know if you have to bore or not, and we will go from there. LSG
 
#37 ·
302 build

OKCoupe, there is absolutely nothing wrong with using your 73 engine parts. You can have your 300 hp and you don't have to have a roller cam or different heads. We can work with what you have. Do you know how to measure the bore for taper ? LSG
 
#38 ·
OKCoupe, there is absolutely nothing wrong with using your 73 engine parts. You can have your 300 hp and you don't have to have a roller cam or different heads. We can work with what you have. Do you know how to measure the bore for taper ? LSG
Great! So it is a 1973 engine? So I know, how did you get 1973 out of the casting number? I do not know how to measure for taper, how do I do that?
 
#39 ·
I just want to say thank you to everyone who has chimed in to give me their help and advice, I really appreciate it! I hope I haven't annoyed you all with all of my questions. This is my first mustang restoration and engine rebuild so its a little scary for me. I want to learn as much as I can in the process also.
 
#43 ·
I don't think anyone can advise you on that without knowing what your true expectations are. If you picture your car billowing clouds of tire smoke and depositing 50' strips of rubber on the pavement, I'd say flip it in favor of a more suitable candidate. If, on the other hand, you are looking to do a budget build that performs about like the 289s of the era (or maybe a little better), you've got a legit shot. Just proceed with your eyes open and never loose sight of what YOU want.
 
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#45 ·
Some of the issues are that you're new. We just don't know you too well so it's hard to give exact help. Post some pictures of the car and of the 302 you bought. Like the saying goes, a photo is worth a thousand words. Again, I'm not trying to push you into what I did. It was right for me. Some of it comes down as to what's available and how much you want to spend. One of the problems with forums, you may just need a tune up and before you now it, you'll be building a 347 with big heads and a big mechanical roller cam. Not what you wanted or needed in the first place. Don't laugh stuff like this happens.

Mustang 5.0's were and are popular swaps. But the last Mustang roller cam 5.0 sold was 1995. That's 22 years ago. These were driven hard. Back in 1995 you could find a lot of 87 to 95 motors cheap because a lot of them were crashed. The last roller cam 5.0 pushrod motor was 2001 in Explorers. Not quite the same motor but still a very good motor. They used much better heads, milder camshafts but the big advantage is they usually weren't driven as hard, usually soccer moms drove them and they are a lot newer so a better chance of finding a lower mileage motor that's still usable without rebuilding. Even with the milder cam but better heads then the Mustang 5.0, the Explorer motor will probably make more power with the same exhaust system of the Mustang. Basically what I'm saying is if you're just looking to install a complete running motor that you don't want to rebuild or modify too much in stock form cheaply this may work for you. I would estimate my motor is about 250 ish HP, maybe slightly more. It may not sound exciting but it runs real well. These cars are light, so you don't need a lot of power.

There's a ton of good used parts and a ton of cheap new parts out there for these motors. Stock heads can be made to work very well and there's nothing wrong with fixing them up other then for the expense of doing this. You could end up spending more then just buying a new set of aluminum heads. On ebay a vendor, Skipwhite sells offshore castings but does all the machining in house with USA made parts from Comp Cams and Crane. for $699 a pair I'm not looking to buy a pair but I think you could very easily spend more on stock heads and make less power. From what I've been reading on late model forums, these are pretty good heads both from quality and the power they make. Personally I'd prefer to buy USA made heads. But from the cost standpoint of either rebuilding stock heads or these. I think I would buy the Skipwhite heads. It's not a recommendation to you just what I think I would do in my case.

Tell us more about your car and exactly what your goals are. Don't be in a rush or let money burn a hole in your pocket. Post pictures, we love them!
 
#46 ·
Ditto, Ditto and for good measure . . . Ditto! Nice to read a level headed post that really sounds like it wants to address the OP's reason for coming here in the first place.
 
#49 · (Edited)
302 build

OKCoupe, Rhutt is correct, if your casting number starts D3AE, its a 1973, if it starts E0AE, its a 1980. Either one is just fine. The older, pre-roller cam blocks are actually stronger because there is more meat in the casting. I'll presume that the new engine is extra ? Does the car have an engine in it now ? Do you still have the original 289 ? Is the 302 apart ? What casting number are the cylinderheads ? If you're looking for 300 or just a little more, we can easily get you there. If you have flat feeler gauges, I'll tell you how to use them to check the bores for taper. LSG
 
#51 ·
OKCoupe, Rhutt is correct, if your casting number starts D3AE, its a 1973, if it starts E0AE, its a 1980. Either one is just fine. The older, pre-roller cam blocks are actually stronger because there is more meat in the casting. I'll presume that the new engine is extra ? Does the car have an engine in it now ? Do you still have the original 289 ? Is the 302 apart ? What casting number are the cylinderheads ? If you're looking for 300 or just a little more, we can easily get you there. If you have flat feeler gauges, I'll tell you how to use them to check the bores for taper. LSG
I bought the car as a roller. This is the only engine I have. The 302 is apart(as in I pulled the heads, intake manifold, carb, etc). The only casting numbers I could find on the heads was a IK6. I don't have flat feeler gauges.
 

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#50 ·
Oklahoma stated in an earlier post that he bought the car as a roller. This 302 is the engine he purchased separately. From what I gather it's probably a long block. I don't recall him mentioning intake manifold or carburetor except to mention that it would need both. In his first post, he did say 95% complete, so I could be wrong.
 
#58 ·
Oklahoma-
With every post, I feel stronger and stronger that you really don't want to build this particular motor. I think a few responses to your initial post placed enough doubt in your mind that you are now second guessing yourself. You cannot proceed with this commitment (time and $$$) unless you are confident.

Several of us have tried to be supportive and offer positive feedback and information, but it really seems as though you are looking for someone to tell you it's OK to hit the reset button and start over. It is! If you have ANY doubts that this motor deliver on your expectations. . . .sell it, get your initial investment back at the local Mustang shop and sit on the engine build for awhile. Rethink it, write a plan and then start fresh.

If, on the other hand you want to proceed, we are here to help and offer advice that we hope will make this process a great experience for you.
 
#54 ·
302 build

OKCoupe, before you trade in the 302, lets determine what is it. Turn the head over, the casting number will be on the underside of one of the intake ports. You don't have to swap it for a roller camshaft block to make the power you want. If you have a 73 block or an 80 block, its stronger than the 1986 or newer roller camshaft type block. And do you have the original 289 engine as well ? Are you going to be using regular unleaded gasoline ? LSG
 
#55 ·
OKCoupe, before you trade in the 302, lets determine what is it. Turn the head over, the casting number will be on the underside of one of the intake ports. You don't have to swap it for a roller camshaft block to make the power you want. If you have a 73 block or an 80 block, its stronger than the 1986 or newer roller camshaft type block. And do you have the original 289 engine as well ? Are you going to be using regular unleaded gasoline ? LSG
I don't have the 289 or another engine. Yes, regular unleaded gas.

Just so I understand all of this correctly. The block doesn't really matter when it comes to getting the horsepower, its the cam, heads, intake and carb mainly? Boring just makes the cylinders good again and doesn't give you more horsepower? Could I have the block vatted, magna fluxed and bored then install a rebuild kit and run the stock heads with the stock cam and a 4 barrel intake and carb? Do I need to have anything done to the stock cam?

Ill turn the head over and see what I find.
 
#61 ·
Glad to hear that you have some time and can proceed at your own pace. I think it is now a given, that the engine you have will produce (250-300 horsepower).
Your machine shop will determine what must be done to the block. Before assuming the worst, do what almost anyone would do (including your machinist) and check a bore or two for a lip where the top ring reaches its highest point. In your picture it would be right about where the black ring starts at the top of the bore. Using your fingernail, try to determine if there is a sizeable lip (or no lip at all). A minimal offset is perfectly normal and may only require honing (assuming the bore is round) to prepare it for new rings. Let us know what you find.

Have you given any thought to the build budget. "As inexpensive as possible" is not a budget. Are you looking to spend 1K, 2K, 3K or more? Pick a number and then a game plan can be written. A small budget is OK as long as your expectations are consistent with it. It might dictate that you do a couple hundred dollars of work to the existing heads and put the money you save where you will get a "bigger bang for your buck". I still believe that you can get what you want . . . . and make your grandpa proud!!
 
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