I have a 350 block casting #3970010 and the crank was shot and the pistons are the dished crap ones so it needs a whole new rotating assembly. I figured it would be really cool to build a 302, (I don't know why but I really like all of the Chevy 5.0 liters 302, 307 and 305) but I am not really sure how to do it with my block. I know they use a 265/283 crank but thats just about all I know. I know building a 383 or 350 is what everyone else would do but I would really like to build a 302. Any information on how to build one with my block would be appreciated.

 

Nothing wrong with using the block but forget about the antique cranks. They used small rod journals. If you want to build a 302, buy a new crank, rods, pistons for making a 302. Price wise, it's probably cheaper to build a 383 and you'll be happier with the results.

 

Yeah the problem is finding a kit or even separate parts to make a 302.

 

Which is because there's no benefit to doing it, so nobody does it. Having a small cube, high revving motor sounds like a neat idea, but the reason that 350s and 383s are so much more popular is because they're better. Even if you want an 8,000 rpm screamer instead of a torque monster, the 350 and 383 will do it just as well as the 302, and will make a lot more power in the process. There's just absolutely nothing that a 302 will do better except drain your wallet.

 

You are probably right but I still would like to know how to make one.

 

Learn how to make a 265, 283, 305, 307, 327, 350, 383, 400, or 427 and you'll know how to make a 302.

 

But I have heard that there are different 3 stroke cranks that were used in the 265, 283 and 302.

 

Why do people make this so hard?

Crank:
http://www.summitracing.com/parts/ESP-435030005700/

Pistons:
http://www.summitracing.com/search/D...8/?Ns=Rank|Asc

You can use the factory rods, or buy new.

If you started with a factory roller block, you could use the "baby LT1" 1-piece RMS 3" stroke crank with the pistons above.

 

Thanks and do you think a factory 283/265 crankshaft would be able to take the power of the 302?

 

Doesn't matter, they all bolt in the same way. If you can build one SBC you can build any of them.

 

I know how to build a small block if I have the parts but I was wondering what parts I needed.

 

The original old large journal 302 cranks were forged or so I have been told. Very hard to find though. I would think that the new crank would be much better.
Also if doing this check for the compression ratio closely. Originally they were about 13:1 compression ratio and for many years that is all you could get. I would assume you could find a lower CR now though.

 

Why would I want to lower the compression ratio? haha

 

To avoid buying $9 race gas.

 

I thought you wanted to keep it with a factory LG4

 

Yeah I am. I am building the 302 for a different car.

 

It would be a drag engine.

 

then why limit yourself to a 302? Is your goal to go as fast as you can afford, or is your goal to spend just as much building a motor with a bunch of silly self-imposed restrictions?

It's pretty much the same as a competitive runner deciding that he wants to run in the olympics, but insists on doing it while breathing through a straw.

 

That is a Valid point. The 383 is over 20% bigger than the 302 so it should give me a pretty decent gain in power.

 

Understand that '55-'67 SBC cranks used smaller journals than '68-up. The factory 302 was produced from '67-'69; therefore, one year used the small journals, the other two used large journals.

All 283 cranks were forged (with a few - very few - exceptions). The last year for the 283 was '67.

If you want to build a 302 for drag racing, then you are going to have to spin it to the moon to get it to move anything with any amount of weight. That means all forged components, a mega-dollar valve train, and high compression to live with the high overlap cam you're going to have to get those high revs (read: race gas).

In contrast, a long-stroke 383 will have more grunt down low and can make great power with no more than 6k RPMs and pump-gas compression. Pretty simple to do with standard racer budget parts.

 

So would a 327 be a good compromise then?

 

No, just 25 cubic inches less deficient than a 302.

 

I don't know. I have heard that the 327 and 302 can turn a lot more RPMs than a 350 or 383

 

You've heard a common misconception. It's not that they can turn higher, it's that they need to.

Power is determined by how much air you can move through the engine. A small engine has to turn more times to move the same volume of air that a larger displacement one does.

 

Again are you interested in spending a whole lot of money to not go faster than a 355/383? What is the driving force behind this? Just RPMs? Im going to go out on a limb here and say that since you havent built a motor or know how one comes apart you havent been on a racetrack either and probably wont spend too too much time on one when you do. With that said...we are all here trying to give you advice that will give you a fast car and not leave you broke yet you keep coming back to ways of emptying your pockets. If all you want is high rpms and screaming motors go get a honda. If you want something that is actually fun to drive build a torque monster for the street. Everyone gets so hung up on horsepower numbers. Horsepower numbers are fine but its the torque that gets you moving from a stop quick. My motor runs out of breath at 5600 rpms but i built it that way and it makes TONS of torque down low.

I dont really mean to come off brash and rude but when more than a few people have come forward and tried to steer you in a better direction and you keep going back to what you want it irks me.

 

I am 16 and I have torn down a 350 and I do know the way a small block works. I am not into that ***** crap. Keep in mind there is about a 25% airflow difference per stroke in between the 383 and the 302 but you can compress a 302 alot more than a 383 and push a lot higher RPMs out of a 302 without rod failure and remember the 302 will be able to breath just as well as a 350, 355 or 383 but it doesn't need as much air in the cylinders as they do, so the fuel should burn better in a 302. The 350s, 355s and 383s aren't the only good motors ever made which some people seem to believe. Don't get me wrong I am not saying that the 383 or 350 aren't great motors or that they aren't better than the 302 or 327. I simply want to do something different every one builds 350s, 355s or 383s and I know why they are great motors especially for getting good power while maintaining a street car, but I don't get why a lot of Chevy guys attack anyone when they want to build any other small block than a 350, 355, 383 or 400. I don't care what anyone says the 265, 283, 302, 327, 307 and 305 are all very capable motors. Some Chevy guys act like they are crap Honda motors, but they aren't. If I had the money I could have any one of those motors push over 500HP easily.

 

Ahhh finally hahaha. The truth comes out!! The old "i wanna be different and build a (insert engine size here)". Never made sense to me before and doesnt now. The reason people build 350s and 383s is there is just more bang for the buck. You can do the same stuff to a 327, 305, 302 or the like and not get as much out of it power wise. Im not saying dont do it but just be prepared for the guy in the next lane from you with the 350/383 that cost the same or less than your build blowing your doors off.

 

You know a little about how it's put together. Still plenty to learn about how it works yet.

Check your math on that again.

Only if you've chosen the wrong parts.

"Burn better" doesn't mean anything. A 302 will need less air on each stroke, which means that it will burn less fuel on each stroke, and make less output on each stroke. Then you'll have to turn more strokes in the same time to makeup for the loss of displacement and make the same power.

Realize then that every small block is the same. Choosing a few different parts than some other guy doesn't make you different, even if it changes your bore and stroke. It just makes you slower and poorer if you choose the wrong ones. A 5 HP Briggs & Stratton lawnmower engine powering your car is different, go ahead and give that a try if different is what you're looking for.

Sure, anyone could, it's only money. But as soon as you actually have to start earning and spending your own money instead of talking about it, you very quickly tend toward the more cost-effective options.

 

What does engine size have to do with it? I spin my BBC 588 to 7500 rpm. If built properly, any engine to reach a desired rpm limit.

The Chev 302 was built for TransAm racing. There was a displacement limit and GM figured out how to make a 302 with a 4" bore to fit into the limited displacement range. The 327 was too big. These engines were built for road racing where spurts to 8000 rpm was common. On the street, having a 302 would be better than a 305 but if you're building from scratch, a 350 or 383 is even better. The larger displacement is from an increase in torque. Torque is what you feel in your butt when you launch from a dead stop. The 3" stroke in the 302 isn't going to make as much torque as the larger SBC engines.

If you're building an engine to fit into a specific displacement limited class of racing then a 302 is a good choice. If you're building an engine to make power or for street use then go bigger.

 

You think the 350s are so great and that the 302 and 327 suck in comparison? Well the highest output 350 had 370HP, the highest rated 302 had 360HP and the highest rated 327 had 375HP. You guys are so right I am so stupid.

 

I agree, but I just hate how some people act like anything small than the 350 is a piece of junk and they are worthless pieces of crap in comparison to anything with displacement of 350 or above.

 

You're not stupid, just inexperienced, and there's something called the Dunning-Kruger effect.

Factory horsepower ratings aren't always accurate. You may have to take into account the under-rating of output for insurance purposes, the difference between peak and average power, emissions restrictions were increased over the same time that displacement was, the difference between SAE Gross and Net ratings, and the fact that even if those numbers were accurate they are completely meaningless for comparing the cost-per-performance potential of engines of different displacement.

There's a huge difference between "not cost-effective" and "worthless piece of crap".

 

I know I used base horsepower numbers. I know that when the 350 came out is when the EPA's reign of terror on the auto industry began, but I think you guys are missing my point. I AM SAYING THAT ALL OF THE CHEVROLET SMALL BLOCKS ARE GREAT MOTORS. I HATE HOW SOME CHEVY GUYS ACT LIKE ANYONE THAT WANTS TO BE A MOTOR OTHER THAN A 350 OR LARGER IS AN IDIOT. EVERY SMALL BLOCK IS A VERY CAPABLE MOTOR. THEY AREN'T PIECES OF JUNK LIKE PEOPLE ACT LIKE. I KNOW THAT THE 350 OR 383 ARE THE BEST BANG FOR YOUR BUCK MOTOR BUT THEY AREN'T THE ONLY GOOD SMALL BLOCKS.

 

I think you're missing our point. Nobody's saying it's junk or that they're not good. We just say they're not worth the time or money.

There are a few good reasons and many bad reasons to build a smaller displacement block, but wanting to do it doesn't make someone an idiot.

 

You know the cool thing about hot-rodding? You can build anything you want!

Relax man, this is just an internet forum. If you want to build a 302 for your first SBC, then by all means do just that. Then take it to National Trail raceway (or any dragstrip), drive it on the street, go to a Power Tour event, and most importantly learn and have fun. And by working on your own car you'll also build confidence in yourself and gain handy new skills.

 

But they are worth the time and money. Maybe me turning my 350/327 block into a 302 isn't worth it but making a 327 would be worth it. If I had a 57 Bel air and it had a 283 building the 283 would be worth the time and the money. Heck if I had a 55 Bel air building the 265 would be worth it. If I had a 1968 Z/28 building a 302 would be worth it. Every single small block being built in a car it came stock in is 100% worth it.

 

Thank you.

 

Nobody is saying otherwise. You said you wanted to build a race motor, not a stock numbers matching restoration. Nobody will criticize a person who keeps their 68 Z28 origional by reusing the stock motor, but that's not what you asked. You asked about de-stroking a 350 to put into your thirdgen to take racing. That's just dumb.

 

And there is another point to this. Ford guys use Ford 302s all of the time. Their argument is "Sure you may the same horsepower or a little bit more but the difference is I did it with 5.0 liters and you did it with a 5.7+ liters" How satisfying would it be to take that away from them? To build a motor better than their 302s, but by using the same amount of cubic inches. No one else thinks that would be fun to do?

 

It might be fun on paper, but in the real world nobody likes paying more than they have to.

Have a look around the racetrack and see how many of the winning Ford guys have swapped their 302 for a 351W.

 

I live in GM territory I don't see too many old Fords, but when I go out of the area to do interiors with my grandpa come to think of it none of them have a 302 or a 351. haha They all have 429s or 289s.

 

Well they are. The 305 is a small bore engine. Any large bore block smaller than 350 CID isn't worth building since it costs the same to build a 350 and you'll be happier with the results.

There's a place for a small displacement V8 engine but it's not for a 3500 pound street car. It's a specialty engine for a specific purpose. Showing up with an 80's car and bragging that you only have a 302 or 327 and not a 350+ will get a lot of questions of why not? If you want to build a period car with a period engine then do it and nobody will question it but anything more modern will need a newer and larger engine to fit in.

 

3500 pounds? My Camaro isn't that heavy. http://www.iroczone.com/2009/10/1982...pecifications/ then subtract the weight of the smog control and A/C my Z28 probably doesn't even weigh 3000 pounds let alone 3500 pounds.

 

It would take a lot more than not having smog and A/C to get under or even close to 3000 pounds. You're inexperienced, we get that. But there are some very experienced people on here giving you excellent information. Use it and dont brush it off, unless you can find concrete evidence proving them wrong. I was like you when I was your age. Over the years I have realized that there are people that have forgot more about these cars then I will ever know. use their knowledge to your advantage.

 

The stock weight on my car is 3169 pounds and the A/C and smog control have to weigh at least a hundred pounds. My car is a 1982 Z28 not an Iroc. Honest mistake though. I get there are some very experienced people here. That is why I came here for advice. I just want to do something different than a 350 or 383 built with a kit from summit. Not that there is anything wrong with that, but just want to do something that isn't done all the time. You know what I mean? As for my Camaro I am gonna buy a LG4 305 for it. I have $70 saved for one. haha (Spent my money on body parts, emblems and paint that still needs to be done) I would really like to build either a 327 or a 302 with my block for a different car though. The 350s and 383s are great motors, but I want to build a motor that you don't see every day or hear about a lot.

 

do it .
Just allow alot of extra $$ for the fuel bill
Some references
"dyno sheets on a 302 built to NHRA "E" Stock rules (stamped rockers, cam, stock Holley #4053, etc.) this one made 389hp @ 5800).
The power is there, but you really have to spool it up to find it - hardly an ideal street engine for that reason, "

"April 69, Popular Hot Rodding track tested a 1969 Z-28 302. Best time with street tires was 14.74 at 95.78 (3.73 gears).
It was also mentioned that with 4.88 gears installed that the Z-28 would turn 13.20 at 107MPH with headers and slicks ".

"I had a 68 Z and it ran a 13.99 @ 105 bone stock (4.56 gears )"

Driven a street car with 4.5X+ gears and a engine that idles at 1500 rpm.
Not fun at the stop lights

 

Until you put your car on a scale, you have no idea what it weighs. Just because a website (Even if it does happen to be my site!!) told you it weighs a certain amount, doesn't mean that your car is the same.

You're consistently ignoring everybody's advice. That makes me wonder why you're asking for it in the first place. You obviously have your mind made up, so just go build the damned thing. Just don't cry when you keep getting pounded at the track by guys who spent a lot less money.

 

That is your site? That is too funny, but I agree thats why I cross referenced a couple websites for a weight and that is the heaviest weight that I got for my car. Remember my car is lighter because it doesn't have all the little things a later one would have. Like the hatch pull down motor, power windows, ect, I believe a fuel injected motor weighs more than a carbed motor, and I am sure other things come into play too. I was asking how to make a 302 out of my block. Not if I should make one or not. Who knows like Apeiron said "Sure, anyone could, it's only money. But as soon as you actually have to start earning and spending your own money instead of talking about it, you very quickly tend toward the more cost-effective options." (Just so every one knows I pay for my own parts, my dad doesn't buy them for me. Although he did buy some paint for me.) I just wanted to know how to build a 302. Will I do it? Maybe, maybe not it depends on what I think when I actually have the money to buy something. I might just end up building a 383, but it wouldn't be bored out. My block doesn't need bored the measurements on the cylinder walls were 4.0001-4.0002. As far as why I would want to build a 302 is that there is just something about the Chevy 5.0s that I love. It may be because I thought both of my 350s were 5.0 liters at a time. (My dad told me they were, I need to stop listening to him. haha)

 

So build something that is not a sbc try a 409 or some other odd motor.

 

Thats a great idea. You hardly ever see a 409. That would be a motor that could give me great power but without doing something that is done all of the time. (by the way for the Camaro I am currently restoring a LG4 305 is going in it.)