Guidelines to building a 302

[mario_82_ZXT]

With my Zs turbo engine slowly dying, I've been thinking about what to drop in it. I really like the idea of these high revving v8s.

 

The basics are these right?

3" stroke

Small journal block with 4" bore

 

Now, to handle high rpms, would a stock 283 crank be able to handle them? A budget build would be a 327 block with a 283 crank right? So I was looking online and found the following:

http://tucson.craigslist.org/pts/424688398.html

 

I'm going to email the owner to get the block casting numbers or see if he knows if it is a small journal or a large journal block. If this will work, is it as simple as swapping cranks and replacing the bearings?

 

If the 283 cranks can be used reliably, there's a few of them around the area for cheap!

 

Thanks for you help,

Mario

[HarrisonTX]

With my Zs turbo engine slowly dying, I've been thinking about what to drop in it. I really like the idea of these high revving v8s.

 

The basics are these right?

3" stroke

Small journal block with 4" bore

 

Now, to handle high rpms, would a stock 283 crank be able to handle them? A budget build would be a 327 block with a 283 crank right? So I was looking online and found the following:

http://tucson.craigslist.org/pts/424688398.html

 

I'm going to email the owner to get the block casting numbers or see if he knows if it is a small journal or a large journal block. If this will work, is it as simple as swapping cranks and replacing the bearings?

 

If the 283 cranks can be used reliably, there's a few of them around the area for cheap!

 

Thanks for you help,

Mario

 

 

Mario

Ah yes, the 302. Thats what i am currently building

Your right, 4 inch bore, 3 inch stroke.

It is not as simple as swapping cranks, and new bearings. You need special pistons too. The part number is L2210a. they run about $350-$400, with varying size domes, i have never seen flatop 302 pistons. Now, the reason for the special piston is where the pin, to hold the rod on the piston is located. like, if you had a 350, and you bought a 383 crank, you would need pistons.

A 283 crank is great. All 283's cranks are forged cranks.

You can get a small journal 327 block, and a small journal

or a large journal 350, 327, whatever block, and a 302 crank, and you would have it then.

Or you could find a 283 block, that would could be bored to .060 and then you would have it.

I think i got that right, once i found all my pieces, i kinda forgot.

 

just find yourself a 3.00 stroke crank, first, then find the block, whether its large or small journal.

 

You will get lots of hell, especially from people on this site that will say, "why not build a 383, its cheaper and more cubes = more power" and all kinds of stuff like that.

Im not building this my motor to be the fastest guy in town, i just want something fun. Plus, these motors make power in the higher rpm's so why would i build a low tq monster, when a 302's power will really come in once i get the car moving.

 

yes, you may spend a little more on this motor than say, a 350. The expensive parts for me was the pistons, at $365, and the virgin 327 small journal block at $200. everything else is normal price, you can score a 283 crank cheep!

what im runnin is in my sig, afr eliminator heads, a stock, forged crank with a fluidamper balancer, an aluminum flywheel, some h-beam rods and the L2210af pistons and a solid roller cam. im going to run a team-g weiand intake, and a nice holley.

[grumpyvette]

I get asked why the 301/302-327-331 sbc engine, is just not seen as comonly any more, the basic reason is the 283-327 they were built from is no longer as comon as the current 350 basic core engine the 383-396-401 gets built from, as the 350 sbc is far more comon.

just some info guys....theres a GOOD REASON why the 302 is less than popular compared to a 383-401 stroker built from a 350 basic block.

THERES NO way a 302 with its 3" stroke and the higher stress on the valve train that rpms over 7000rpm that the 302 sees will match the results and dependability a 383-396-401 stroker combo with its 3.75"-3.875" stroke and under 6500rpm valve train stress will produce

lets say a 302 can produce 1.25-1.4 hp per cubic inch, you can do the same with a 396 sbc

your looking at say 410 hp for the 302 and a similar 396 sbc costing almost the same will produce 535 hp with the same hp per cubic inch WITH LOWER VALVE TRAIN STRESS, its a FACT your far more likely to have valve train problems at over 6500rpm than under that rpm

theres also a much faster ramp up on the torque curve with the larger displacement.

we USED to build 301-327-331 sbc when the cylinder heads flow limited the effective displacement that could effectively be fed, those days are long gone, with the current aftermarket heads.

 

example

 

http://airflowresearch.com/articles/article031/A-P1.htm

 

http://www.chevytalk.org/fusionbb/showtopic.php?tid/131229/

 

http://www.bracketmasters.com/small_block_stroker_383_cu.htm

 

http://airflowresearch.com/articles/article014/A14-P1.htm

 

http://airflowresearch.com/articles/article016/A16-P1.htm

 

btw USING A HYDROLIC LIFTER VALVE TRAIN in a 302-331 SBC thats built for MAX HP,is about as useful as snow shoes on a snake

 

ID also point out the differances in bearing sizes and the difficulty in building good compression with flat top pistons with the shorter stroke combos

 

http://www.mortec.com/journal.htm

 

http://www.mortec.com/borstrok.htm

[mario_82_ZXT]

It is not as simple as swapping cranks, and new bearings. You need special pistons too. The part number is L2210a. they run about $350-$400, with varying size domes, i have never seen flatop 302 pistons. Now, the reason for the special piston is where the pin, to hold the rod on the piston is located. like, if you had a 350, and you bought a 383 crank, you would need pistons.

A 283 crank is great. All 283's cranks are forged cranks.

You can get a small journal 327 block, and a small journal

or a large journal 350, 327, whatever block, and a 302 crank, and you would have it then.

Or you could find a 283 block, that would could be bored to .060 and then you would have it.

 

Ahh ok thanks for that. There are actually a few complete 283s locally, so I think it might just be easier to bore it out and stick those special pistons on there. Do I need different rods as well? I figure I would also need an aftermarket cam/springs/retainers everything for the higher rpm.

 

grumpyvette, I wanted you to chime in!. Would dependability be worrisomely bad? One reason for a peppy motor is because I currently don't have the money to flare out the car and I think I would find it very difficult to put power down. This car's primary duty is going to be road racing, not drag. I would also like to eventually build some 180 degree headers just for the sound (unless I could find a flat plane crank). Is there anything that can be done about the valvetrain stress that won't cost an arm and a leg?

 

It's mostly an idea to be a little different

Mario

(currently reading those articles)

[grumpyvette]

I used to build a few road racing engines, and while wide rpm ranges can be handy, responsive and near instant torque and accelleration the larger displacement can provide generally (with the correct gearing) alows LESS gear changes and faster accelleration out of the corners, and more effective compression brakeing off the throttle,building a valve train that lives over about 6000-6500rpm tends to become far more expensive, especially over 7500rpm and up

[mario_82_ZXT]

That's understandable.

 

I also keep running across threads that are 302 vs 327 vs 350. The point of the matter is that I'd like something that rev's to about 6.5k comfortably like the stock L series, which is why I was thinking 302.

 

I then looked online and found out about the 377, but I can't find any 400 parts locally. There's also the 327, and there's actually a large journal longblock locally for $150.

 

What do you think about something like a 327? From what I've gather in the corvettes, the factory redline was set at 6k to 6.5k rpms. Can they sustain those revs?

 

Thanks,

Mario

[HarrisonTX]

Well, if your only wanting to see 6.5k, then a 350 will do that just fine. I run a 355, in my malibu. I have a stocke forged 350 crank, some forged eagle rods, and probe pistons, a stock flywheel, and a stock balancer. The rotating assembly was professionally balanced, and it spins to 6500 just fine. So 6,500 isnt asking too much man. Just make sure it is balanced good, and dosnt vibrate apart

 

I do agree 100% with grumpy about the valvetrain stress, but Im running afr eliminator's, which come stock with good vavles, and my solid roller cam will only be about .530 lift, so the stress wont be too much. I will dyno it, and i expect around 450 at the crank

[mario_82_ZXT]

I seriously wouldn't mind a higher rev limit. I just don't want something that turns slower then the motor it is replacing. I've read the 302 peaks power at 6.9k, which was originally why I was looking at it.

 

Being as how a 302 is buildable on a jy budget (I've even located used pistons) I was wondering if something like this is doable with other SBCs. Or will a 327, or 350+, require expensive parts to spin +6.5k reliably?

 

Mario

[HarrisonTX]

I seriously wouldn't mind a higher rev limit. I just don't want something that turns slower then the motor it is replacing. I've read the 302 peaks power at 6.9k, which was originally why I was looking at it.

 

Being as how a 302 is buildable on a jy budget (I've even located used pistons) I was wondering if something like this is doable with other SBCs. Or will a 327, or 350+, require expensive parts to spin +6.5k reliably?

 

Mario

 

I just told you my 350 spins to 6,500. and it is dead reliable. Thats with stock double hump heads, and a mild hyd. cam.

 

You can build 377, which is a destroked 400 will rev good, and wont be too much difference in price. a 327 would be good too, probably rev higher than a 350. whether its 7,000 rpm in a 302, or a 400, 7,000 rpm is still 7,000 rpm. Its gonna be hard on the valve train parts no matter what the cubes are.

a 350 can see 6,500

a 302 will see 6500 +, faster and easier, in my opinion

[280zwitha383]

A 302 will not get to it's peak rpm faster than a larger cubic inch engine similarly built. When you say easier that is arguable also, valve train parts don't know what's rotating below them (i.e. if you had the same valve train in both and spun both engines to the same red line they would both last just as long unless you take into the fact that the larger cubic inch engine will get to its red line faster which would theoretically cause more wear).

[HarrisonTX]

A 302 will not get to it's peak rpm faster than a larger cubic inch engine similarly built. When you say easier that is arguable also, valve train parts don't know what's rotating below them (i.e. if you had the same valve train in both and spun both engines to the same red line they would both last just as long unless you take into the fact that the larger cubic inch engine will get to its red line faster which would theoretically cause more wear).

 

What you said about the valve train not knowing whats below it, i just said that right above your comment when i said 7,000 rpm is 7,000. I get that.

 

Think about piston friction, often over looked.

 

take a 383 vs a 302, "both engines have the same bore, the 383's piston friction at 7,000 rpm will be much greater due to the .750 longer stroke

 

280z, you said this

"A 302 will not get to it's peak rpm faster than a larger cubic inch engine similarly built"

If you a 383 will reach 7000 just as fast a 302, i strongly disagree.

If you are saying i 383's max power is say 5,800, and a 302's is say 7000, and they will reach their individual peak at the same time, i think thats impossible to say.

 

Mario, man this is going to far lol. If you want a 302 build it. if you want the best bang for you buck go 383, im not denying a 383 will be cheaper (maybe) and make more power. I am just saying a 302 will be fun. Im not trying to be the fastest guy in town, im just gonna have a good time. I dont wanna be like 90% of the ppl with an ls1, or a 383, im doing my own thing.

 

Anywho, 280z, i love you still, and i live in lubbock. I have never rode ina v8z, how about i come down there

[mario_82_ZXT]

Hahahaha

 

I guess it has gone a little too far. I'm going to price out the 302 with everything that I can get locally. The only thing I don't like so far is that this is probably not the best engine choice for a college student budget

 

At least I have a daily driver ($750 SE-R FTW Woo!)

 

What I was going to reply to you was that your 355 is "professionally balanced" and that sounds pricey to me, which is why I commented about the other engines. I too don't really care about being the fastest in town (I just don't want to be the slowest), and my Z has too much character and I feel like I'd betray that if I did a ho hum swap.

 

Thanks so much for your support!

Mario

[mario_82_ZXT]

PS Do you have to use those pistons?

 

They raise the compression to 11:1, which seems quite high for pump gas. Or is that more for period correctness? Is there something lower that might support forced induction or giggle gas later that might be more easily found?

 

Thanks,

Mario

[jt1]

posted by HarrisonTX

 

If you want a 302 build it.

 

Bingo. There are many combos, build the one you like.

 

I'm working on a 302 now for no other reason than the hell of it.

 

John

[Pop N Wood]

This has been one of the better threads on 302's!

 

BTW, an LS1/2 will easily turn 6500 RPM.

 

It is typically valve float, and not engine stroke, that limits RPM. Valve float and airflow, like Grumpyvette explained.

[woldson]

Hay mario call me 714-9798, your in spokane right?

[mario_82_ZXT]

http://www.hotrodders.com/forum/chevy-302-help-4624.html

Another way to build one.

 

With an LT4 3in crank (large journal) and 5.94" rods, then you can choose the compression ratio with the heads using a 4" bore block. I'm going to see if I can find one of these locally.

 

The stock LS1 redline is 6.2k rpm but I've heard with upgrade valve springs and retainers you can spin them close to 7k rpm.

 

Woldson, I'm in Tucson AZ, but if you still need me to call you I will

Mario

[280zwitha383]

If you a 383 will reach 7000 just as fast a 302, i strongly disagree....

Anywho, 280z, i love you still, and i live in lubbock. I have never rode ina v8z, how about i come down there

 

A 383 similarly built will get to whatever rpm you want faster than a 302 similarly built simply because the 383 will accelerate faster. If you would like, I would go so far as to say the 383 will rev just as fast as a 302 without a load also. In this case, the more power you make the faster something will "rev".

 

If you ever come down here send me a pm. I've never visited personally with anyone who has done any sort of engine swap so I will enjoy it. I'll show you how fast a 383 can rev

[HarrisonTX]

A 383 similarly built will get to whatever rpm you want faster than a 302 similarly built simply because the 383 will accelerate faster. If you would like, I would go so far as to say the 383 will rev just as fast as a 302 without a load also. In this case, the more power you make the faster something will "rev".

 

If you ever come down here send me a pm. I've never visited personally with anyone who has done any sort of engine swap so I will enjoy it. I'll show you how fast a 383 can rev

 

man, do you have anything to base this on?

I just gotta say, really dont think you right

 

"both engines have the same bore, the 383's piston friction at 7,000 rpm will be much greater due to the .750 longer stroke"

 

piston friction will cause slower revs. I think your crazy man.

 

but anywho. you have never met anyone that done a motor swap? who the heck do you hang out with? Did you do your own work? I will for sure come on down, what is it 2 hours from lubbock>?

[Pop N Wood]

"both engines have the same bore, the 383's piston friction at 7,000 rpm will be much greater due to the .750 longer stroke"

 

piston friction will cause slower revs. I think your crazy man.

 

You are right, but what I think he is saying is a 383 has a bigger push. More power trumps more friction.

 

I would think the piston friction will be small compared to the energy that must be pumped into the heavier rotating mass.

 

And when in gear, the engine that revs the fastest is the the one in the car that accelerates the fastest. Once again, power rules. In that case the 383 will almost certainly win.