Small Block Pontiac 307

[68 Stang]

Sorry that I haven't posted back with the numbers before now, but here they are. I had a GM 19 and a 388520. I believe that the second number is right, but if there is anything that you can notice that wouldn't be right, I would be glad to recheck it. Hope this is what your looking for. By the way, I posted this also in the Chevrolet forum(which I haven't gotten much response or help) and one guy told me to use it as a boat anchor...Then he told me that I need a 350 or 400ci! He thinks I could afford that, is he crazy? My goal for this engine is to get it just as fast as a 350, but still have the 307 block. I doubt I will make it to that goal, but it's worth a shot. Thanks again for your help!

[Dan_in_WA]

I'll check on the numbers and get back to you.

Umm... As far as the boat anchor thing? This guy has never heard of the 283 Power Pack, or know a whole lot about small blocks.

What you and I have are 283 blocks with a 327 crank. The main difference between the 350 blocks and the 283 blocks is 1/8" of bore diameter.

Just 1/8".

Here's another formula, for your amusement:

Cubic Inch Displacement (CID) = Bore x Bore x .7854 x crank stroke x number of cylinders.

Bore squared, times .7854 gives you the area of the circle.

Type to you again soon!

Dan

[Dan_in_WA]

I typed "small+block+Chevy+520+head" into the Google search engine.

Looks like you have what is known as 283 "Power Pack" heads. CONGRATULATIONS!

These heads are just what you want for street use; small combustion chambers (59 to 61 cc) and have a little better cooling around the exhaust valve, if I read all that right.

These are not 'emissions' style heads at all. No valve shrouding or any of that other Mickey Mouse stuff GM did in the early '70's in the name of "Clean air". [I'm not against clean air - but I don't like killing engine performance just because some bureaucrat says to.]

1.72" diameter intake valves, 1.5" diameter exhaust valves. Since it's a new valve job, I would personally disassemble and inspect it, but leave it alone unless I find something not right, like a valve leaking.

With future fuel injection and flat top pistons, expect to make about 325 peak HP and get 17 to 22 mpg, depending on your rear-end gears.

Type to you later!
Dan

[68 Stang]

Wow. 325 peak horsepower! That is just what I am looking for! Not and insane amount, but surely enough to show that guy sitting next to me who's boss. So the heads sound good, eh? The pistons that are currently in the 307 have notches cut into them for valve clearance. Do they really need that, or should I put flat-top pistons in as you mentioned? And the crank is a 327, thats cool. What about the cam, you think a 350 stock cam would be good, or the 307 stock cam? Or should it be a mild aftermarket? Oh, by the way, do you have any idea on torque numbers?! I am excited, it sounds like it will be a worthwile buildup after all!
Thanks for all the information!
Grant

[Dan_in_WA]

Originally Posted by 68 Stang

Not and insane amount, but surely enough to show that guy sitting next to me who's boss.

Ah, and this leads me right into the most important concept in hot rodding... You will receive a PM tomorrow.

Before the cam is finally chosen, you'll have to know several things - like the car the engine will go in, final drive ratio, weight of car, transmission type, and so forth.

As far as the pistons are concerned, you may be looking at flat tops. A flat top piston will have the four 'eyebrows' cut into it. A dished piston has a noticeable dish in it. You definitely want flat tops! That will help keep compression ratio up around 9.5:1 or so; there is a formula to figure out compression ratio too.

I'll post it when I find it.

Welcome to Automotive Engineering 101! (No pun intended)

[68 Stang]

Wow, the PM was really good! Don't worry, I followed you all the way.I re-checked the numbers on my heads and it wasn't exactly 388520 as I stated before, but wasn't far off, it was 3884520. I wouldn't expect this to make any difference but tell me if I am wrong! So...about torque and accelaration...I want lots...and lots...It's a great and horrible thing that I already have "the bug" at my age. I can't afford, but I love it! I don't have any idea of the weight of the '48 or '49 Ford that I would like to put it in, but I do have an idea of transmissions. I was thinking possibly a 700R4 for auto or T56 for manual. I realize that both are out of my price range, but I will deal with that when the time comes. How much would a port and polish job cost on my heads? After how you were explaining the importance of airflow, I realized that I want to make those babys flow! I looked them over again, and all the parts really seem to be in good condition. Really looking forward to your posts!

Grant

[Dan_in_WA]

Yeah, it's the last 3 digits of the casting number on the head, that tell you the basics of the head you have. 520 is the 283 Power Pack head, 186 casting would have 2.02" intake and 1.60" exhaust valves, and so forth.

Before the cam can be chosen, you'll need to acquire the transmission. Then the question of automatic vs. manual will be answered. Actually, it would be preferable to get the truck, too. Is there a weigh station on a highway near you? You might be able to have the thing weighed there.

To get an idea of what head work will cost, just call around to your local machine shops. Take a look through the Yellow Pages, and call a couple different ones. If there's a race track in your area, or any racers, find out which shop they use. You won't need (or even want) a major port/polish; what you're after is a good general clean-up of the ports with some blending of surfaces in the area of the bowls of the ports, where the A/F mixture turns the corner.

This is easy to do! Just figure out which shop is the best for your needs, tell them what you are after as far as performance, drop your heads at their door and they will do the rest.

Velocity of the air is critical - you don't want the ports hogged out to get those big numbers on a flow bench, because that's not where the engine is going to be running [high RPM] most of the time anyway. When air velocity drops, fuel can drop out of suspension and start to puddle around the port walls, and it doesn't do anything for power!

For top street performance, all the major pieces need to be present (engine, trans, chassis) to see what you have to work with. The hottest hot rods have been completed on paper before they took shape in the garage - because of the thought and design work that went into them before they simply became another money pit. This doesn't mean you're stuck before you get your truck and the trans - but you do have to know some things for sure before you start laying down ca$h for things like camshafts and headers!

For instance, if you decide you're going to be using the 700R4 with a shift kit and 3.5 rear end gears, but all the sudden someone gives you a killer deal on a T56, that will make a big difference in which cam is optimum for your application. And if you've already laid your money down for the cam, well, you get the idea.

More later!

[68 Stang]

Alright, so don't jump the gun, or I lose the very little bit of money that I have. So, what should I do now? I don't want to push my dad for getting the truck, because I am lucky he is allowing me to have the engine really. Is there anything else to tend to while waiting to get a little older, and get my dad talked into that truck? Should I start saving for a boil-down of the engine, to get all that crap off? Or, should I start hunting for a transmission? If so on the transmission, should I go to a junkyard first, or is it better to bite the bullet and buy new?(that would kill the project most likely )Your posts have been a great help. Looking forward to more!

Grant

[Dan_in_WA]

I'd start by saving the money for the hot-tanking the engine will need. It will go over a lot better to have a clean block lying around - wrapped up in a large trash bag to keep the dust and junk out - than to have a greasy, crud covered junk engine sitting in the corner looking ugly!

Keep an eye out for the transmission, but there's plenty of time. You may even be able to scrounge one from a shop's graveyard pile out in back. A junkyard will be a fair bet at best - they're in the business of making money, not helping out a n00bie hot rodder; which is too bad for them. I still frequent the salvage yard I got my first break from when I was 15. Probably spent several thousand dollars there, over the years.

I'd ask the local junkyard if they have an old core lying around, "for educational purposes". Got a school science fair coming up?

Personally, I use Rustoleum Hard Hat paint (in the BIG can) for painting things like valve covers, oil pans, timing chain covers, and all the other sheet metal like that. I go with black on the sheet metal and gray on the castings. The water pump gets flat white. Just look at the front cover of "Chevy Performance" book at your local auto parts outlet - that's where I got my inspiration. [The Best Ideas are stolen.]

Do you have the engine yet? Clean-up is the first priority. Then it needs any necessary machine work, like a bore job or whatever. After that, you can paint it. The sheet metal can be painted at any time.

A few words about prepping for paint: The engine paint job will only look as good as the prep work underneath the paint!

1) Clean the parts. Scrub the bejeebers outta them. If the original paint is holding to the metal and doesn't want to come off, that's fine. Just NO dirt, grease or oil.

2) Scuff the surface that will be painted. A green Scotch-brite pad works best - my wife is constantly running out of them for use in the kitchen. Wet-or-dry sandpaper (220 - 320 grit, use wet) gives excellent results, too.

3) If there is any bare metal, use Metalprep (TM) or something like it. Read and follow the directions. This is available at any paint supply store.

4) Buy a 99 cent Tack Cloth for use just before you spray any of the parts. Wipe down the surfaces you're about to paint, then paint 'em. This will remove all traces of dust and other stuff that gets into spraycan jobs.

Using this method, I've gotten some real professional looking jobs done with minimum cash outlay. If the sheet metal or casting surface is extra, extra cruddy, DOW oven cleaner works wonders. Removes old paint, varnishes, cruds, slops, etc. etc. and all for about $2.25 a can!

Just wash and rinse thoroughly after using oven cleaner, and WEAR GLOVES! This stuff will burn your hands royally. BTDT. Didn't like it.

Good luck, and Happy building!
Dan

Edit:

Reading back through the posts, I noticed that your dad restored a Mustang, and you have that 305....... And the 307 should be there by spring of next year.

Seems to me you might have some trade-able parts from that 305; after all, it uses the 3.48" stroke 350 crank, and what are the casting numbers on the heads? What is the overall condition of the engine? Do you have things like the oil pan, valve covers, etc. to practice painting on? You may not have much, but you do have a little swapping material here. It's still an asset.

Is your Dad a car guy? Fords his favorites? Or did he just want an original 'stang?

Lastly, a word about your studies: You're gonna need the math in this game, to ever be any good at it. Take computer courses too. The schools won't teach you the things that you will need with fuel injection, but are kind of a starter course you can at least build on. If your teacher is any good, that is. If your school offers an electronics course, take it. You'll really need it bad when it comes time to dive in to GM's ECM stuff.
Fortunately, you're 14 and still have some time to get your feet wet in it.
The deeper you get into hot rodding, the more you'll need skills with Algebra and Geometry. In fact, there comes a point that you can't go on without it.

Discussions of rod ratio, piston speed relative to crank angle, valvetrain geometry, and all the really in-depth topics that separate the truly knowledgeable people from the ricers, well, those topics can't be discussed without referring to mathematical formulas and terms!

Just look at some of the formulas I've posted so far - those are the easy, teaser ones. And we haven't even discussed the subject of making the car handle, yet! That's an engineering discipline in itself.

Are you in Algebra, by any chance?

Dan

[68 Stang]

Yes, I am in my second year of Algebra, Algebra 2/Geom. Don't worry about the painting. After restoring the Mustang, I think the painting is under control(not that you knew this). I was in charge of all the interior door panel painting, and the man that gave me the engine is an old-school rodder thats retired and he paints cars. He is the one who painted our Mustang. I am really wishing I knew how to post a pic right about now... Also, if I wanted to, I could spray it with a gun instead of a can, you know like with the same paint as the car so it will match. I dunno though, I have the laquer thinner, and am using it to clean parts. It works great! My dad likes all cars, he has a Mustang though becuase he has had it since high-school. It was my granpa's. The 305 engine is in bad bad shape. When I remove the oil pan, I found a chunk of piston, metal shavings, a gear from the oil pump, and just some really disgusting oil that I don't think was EVER changed. The valve covers had small dents, and the edges are bent, so they would take too much work for what they are. The oil pan had that disgusting sludge stuck in it, but I suppose you could reuse it if needed. I will save the pistons just in case, 'cause you never know when you might use them. Also, on getting the old paint and grime off the engine, what about a sand-blaster. Had any experience with them? Are they worth the trouble, or a waste of time? Once again, thank you for all the advice.

Grant

[Dan_in_WA]

I've used a sand blaster at home and work, they will do the job on the castings. The sheet metal parts will get badly pitted and tend to warp, though. The blast media acts like millions of tiny hammers hitting the surface. It sure cleans a casting, but the thinner sheet metal will distort, in my experience.

Prepare to clean up a mess if you use one of the $20 guns from the hardware store. Blasting material goes everywhere unless you have a booth to keep it contained.

Will write more later,
Dan

[68 Stang]

I was just thinking, pics would probably help, eh? I will take some on our digital, then try to post 'em up! I will take the 305 first, and get the 307 asap. By the way, I was working on my 307 this past weekend, removed all lifters, cleaned and greased them. I got pistions and everything free and moving. I'll go get those pictures now. Write later.


Grant

[68 Stang]

I just realized that I don't think I posted any specs on the engine. When I checked the number in the book, it listed as the '69 Pontiac small block 307 with 200 horsepower and 9.0:1 compression. I don't want to go with a roller motor, simply because I do not have the money. I would like to get 300-325 horses out of it with a cam, the head swap, headers and other small things. I doubt I will make it, but I will try to shoot high! The 284 power pack heads have had larger valves installed for use with unleaded gasoline. Found some cool aluminum valve covers and matching air cleaner that a guy had on his 350 and wanted to sell because they oxidized. I will put that zoop sealer on them, and the shine should last. Not that asthetics matter, but they are still cool! I think I will go with bosch plugs, +2's maybe? I will have the crank re-balanced, get the cam bought and in, and hope for the best. I am thinking on using a stock 350 cam, more power without the really rough idle. Hope those specs help some. Looking forward to your posts.

Grant

[Dan_in_WA]

Originally Posted by 68 Stang

I would like to get 300-325 horses out of it with a cam, the head swap, headers and other small things. I doubt I will make it, but I will try to shoot high! The 284 power pack heads have had larger valves installed for use with unleaded gasoline.

Grant

You should hit your goal with little trouble! This is the range of .9 to 1.0 HP per cubic inch, which is easily attainable with the proper choice of intake, cam and exhaust.

KEEP THE HEADS YOU HAVE!!!! These are EXACTLY what you need for street use, and with the bigger valves (assuming 1.94" intakes) they just can't be improved any more, IMO.

Could you verify valve head size for me? I imagine the intake valves were enlarged from 1.72" to 1.94", and the exhaust valves are still 1.50" in diameter. This is how the "1.94" heads came, when referring to valve sizes and not casting numbers.

So far you are absolutely on the right track. All you have to do now is select the intake, exhaust and cam for the RPM range you intend to run.

Header primary pipes should be no larger than 1 5/8" dia, and I'd give strong consideration to 1 1/2" dia primary pipes, unless you wind up with an ultra-light chassis. Best thing to do is contact Headers by Ed.

Intake is already pretty much taken care of. Two barrel manifold to start, then a later upgrade to fuel injection. Those will be stock systems, or modified (tuned) stock systems, so......

Pay EXTREME attention to the camshaft you install! The best advice I can give here is to start doing some major research. Pick the cam that will work best with your intended future FI set-up. You'll need to know whether the FI system will be Speed-Density or MAF. The two-barrel carb and manifold will be an interim intake system until you get the FI system, so I'd give it a good clean-up and maybe a rebuild kit, but not worry about trying to 'optimize' it.

Tull Systems in California does FI set-ups; they may have a website. I'd ask their recommendations on what to run as far as the cam. A stock grind is a safe bet, but there are a lot of stock performance 350 grinds and some will work better than others with FI, due to things like reversion and overlap. I say ask someone who knows more about these things than I do - the major cam companies would be a good start.

Stay with a hydraulic grind, naturally. Modern hydraulic cams can be ground with as wild a profile as you'd ever want for the street, and we're talking about making power in the 1800 to 5500/6000 RPM range, or so.

Too much lift on a cam profile just robs power from the engine to force the valve down further against the spring - and I'd rather use the power to turn the rear wheels than mash the valve down more than it needs to be to properly fill the combustion chamber! To re-state this: At lower RPM ranges, the valve does not have to come off the seat as far to properly fill the cylinder. The fuel/air velocity isn't as high at 3000 RPM as it is at 6500 RPM, and the valve is less of a restriction at the lower RPM.

I will explain this in more detail later - lunch break is over.

[68 Stang]

I know that I can get major horsepower from the cam, but I would rather not have that un-appealing lope that can barely stay running. That's why I am planning on the stock 350 cam, for a little bit of grunt, but not much lope. Not too much that the magnaflows can't cancel out. I added all my parts that i plan on using, and it added up to $537. Not too bad, eh? I can't wait to hear it run(not that I will ever get it running!). I don't know how soon the FI system would come, but probably before I would even be able to get the truck, so It might never have the 2 barrel on it, I still don't know. Thanks for the response, it makes me want to work more and more on the project.

Grant