DIY Chevy 302.

So, I've had my eye on this old 327 for a few years now. It looks like its sat in the barn its in for atleast 20. I don't remember a whole lot bout it except that its from the late sixties, has double hump heads and a carter competition carburetor. Dude wants 700 for it, its kept the manifolds somehow, but other than that its been sitting semi-exposed at the open part of this barn.

My cousin told me today that he's taken the crank out of this old truck we have on grandma's farm. I'm gonna say its a late fifties Chevy 70 series, dual rear wheel, COE type of truck. It was wrecked and parked many many moons ago. It has a 283 with a steel crank, I wanna say its forged, we think.

Now I dont know if the 327 is a small or large journal, I haven't seen the motor in years, and for all I know its locked up, cylinder walls grooved, and all sorts of bad stuff. I think the word of the old man who has it, but he's had alot of stuff for a long time, and his memory is slipping a bit. His place used to be like the stuff you see on American Pickers but he's let alot of it go.

Now, other than decent heads, and the combination of 283/327 internals, is there anything special that has to be done. Say, can you use the 327 rods or do you need a certain length? How will I be able to judge the small/large bore of the block?

I'm interested in this because, as much as I love the 350, 355 and 383 SBCs, they are really common, and the 302 has always been my favorite motor. It makes goober tons of power, revs to the moon, and I wanna see the confusion on peoples faces when I pop the hood and tell em its a 302 or that its just a little ole 5.0

I wanna stay fuel injected, but a TPI manifold would not work on a DZ302 replica at all. I'm thinking of a TPIS mini ram, but those dudes are expensive. I've seen people convert LT1 manifolds for SBCs, although I'm not sure of the cost of that either.

But most of all, I've never actually assembled and engine from the mains up, and have it run. I did in tech school with dummy engines a time or two, but never heard one actually fire. I come here because most of you like the quirky, different stuff too, and I know I can find some real tech here, not just a bunch of eablers (though that's good too.)

Oh, and FYI, the car is a thid gen Camaro. Auto, t-tops, right now has a 305 and its all original. I don't plan on making a crazy track car with this, just a fun street car that has a nice idle, some wow under the hood and enough power to make me giggle like an asian school girl.

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if it's a 67 and earlier 327, then it will be the small journal block. the 283 crank will drop right in, and either the 283 or 327 rods will work. buy a set of 302 pistons, get it balanced up, and the rotating assembly is done.

it would be wise to throw away the main bolts and get studs put in, along with new bolts in the connecting rods. the mains will need to be honed and the rods resized..

if it's a 68 or later block, then it will be a medium journal block. you can get thick bearings to use the small journal crank in that block, so that's not an issue. get a solid lifter cam for it and shift at 8000+ rpm when you want to play.

The best factory produced head for that block is the Vortec truck head from the 1990's; paying a premium for double hump heads does not make sense unless there's some racing rule that makes them useful.

I have no idea why you'd want "302" pistons since it's a 327 block. So, you know, grain of salt, I may not know what I'm talking about with that one but when I looked into this... you get the idea.

I have a set of double hump heads you can have if you pay shipping (they are even the same casting number that came on the 302). This is the last chance and they are going in the trash. lol

Bench Racer (BowtieBandit) wrote: ...... I'm gonna say its a late fifties Chevy 70 series,.... 283 with a steel crank,.....Now, other than decent heads, and the combination of 283/327 internals, is there anything special that has to be done. Say, can you use the 327 rods or do you need a certain length? How will I be able to judge the small/large bore of the block?

Word of caution. The early cranks had rope seals, the 60's 327 did not. The 327 (non 2 bbl) rods are WAY better than the 283 rods.
Easy ID on small or large journal - look at flange at back of crank - round wth notch = small / rectangle with notch = big

$700 is way too much for an assembled and uninspectable 327. If it is exposed it will cost $ to machine. Very high likelihood that at least one head is cracked. If its a large journal, it's a $200 piece. And the thick bearing to use the small journal crank are expensive. If it is a small journal with the weak rods it may be a $300 piece and with the better rods $350.

http://www.jegs.com/i/Clevite/695/MS1110H/10002/-1 (going off memory on the P/N). Side note - I use the H-series for high rpm's and the land speed stuff, and HD-series with Aluminum rods. P work under 500 HP, you'll beat them up at 520 hp in a 400...if you hook. P-series stuff is what you get at the local parts stores.

Don't get caught up in the camel hump hipe. I give my cores away to 2 buddy's who use them on dirt track engines. I recently bought a fresh set of 2.02/1.60 with screw in studs for $80 and picked up another set last summer for a pair of tires with the 327 LG. The quality and performance of modern stuff has kicked the tar out of the camel head prices. Rightfully so, a well ported camel goes 230-240 cfm at 28" and can go as high as 254 cfm professionally prepared. A Dart with 4 hours of work will go 252, and race prepped we are seeing 300 cfm.

Don't get me wrong, I enjoy the old stuff too. I have (2) 1955 265, (1)SJ 327, (1)LJ 327, (4) 400, (6) 283 cranks, (4) sets of power pack, (2) set of camels - both 2.02.., blah, blah, blah, the list goes on. It's not worth doing if you can't get into it right and the stuff is still out there. Just remember, the legends are weak, I was there. Mystique is expensive.

Just remember guys, those guys didn't build small engines because they were better, the 302 was created because of the rules. Cubes rule with the cylinder heads and metallurgy we have today. I would never build a 302 when I could build a 327 or 350 or 400 for nearly the same money.

You could build a Stroker 327 instead if its the large journal crank...... one of the rare and valuable 350's.

Thanks for all the help guys, upon further research last night, I found some forum where someone was saying take a newer 350 roller block, with 1 piece rear main, and put a 3.00 inch crank in it. Makes since, since I'd really rather have rollers and such anyway.

All in all I was looking to do something different, but it looks like 350 wins... again.... dammit.

I've seen 331's pulled from 327 engines, but like was said, the price is a bit much for one that I have no idea what kindof shape its in. I wasn't really planning on using the double hump heads, but I was wanting to stick with a mini-ram style of manifold, so vortecs were out. Carbs aren't all bad, hell we don't even do emissions testing here, but I think I'd be open to going backwards. Not like a TBI is all that sophisticated anyway.

Again, thanks for the input guys!

Bench Racer (BowtieBandit) wrote: All in all I was looking to do something different, but it looks like 350 wins... again.... dammit.

A 400 with a stroker aftermarket crank is still different, and way more powerful. A few years ago Hot Rod ()I saved the article) built an amazing 440 ish with an aftermarket Dart block that made an incredible amount of power. You can still be different and make power.

Honestly these days anything that's not an LS1 is different. Build a 383 stroker out of a $50 350 and stick it under the TPI and keep telling people it's the 5.0.

tuna55 wrote: Just remember guys, those guys didn't build small engines because they were better, the 302 was created because of the rules. Cubes rule with the cylinder heads and metallurgy we have today. I would never build a 302 when I could build a 327 or 350 or 400 for nearly the same money.

The only reason (note - I did not say good reason) you build a 302 is for cube limited use. I have a 350 block with a DZ crank ofset ground to 2.9 stroke SJ rod size if you want to see one. A 302 is way more expensive to build than a 350. The piston cost is ridiculous. The offset grind allows a 350 5.7 rod piston to work with 2.9 stroke and a 6 rod - deck height adjusted. FWIW, we are doing some tiny inch engines also...again only for cube limit reasons.

Save money, do a 350...spend savings on everything else...these days getting something done is different enough.

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pres589 wrote: The best factory produced head for that block is the Vortec truck head from the 1990's; paying a premium for double hump heads does not make sense unless there's some racing rule that makes them useful. I have no idea why you'd want "302" pistons since it's a 327 block. So, you know, grain of salt, I may not know what I'm talking about with that one but when I looked into this... you get the idea.

you get the 302 pistons because of the shorter stroke of the 283 crank (3.00") compared to the 327 crank (3.25"). the pin height is lower so the same length connecting rod can be used.

the "283 crank in a 327 block" was called a 301 when hot rodders were doing it before Chevy did it at the factory for the 67 Camaro Z/28 to be homologated for the new trans Am series and called it a 302. then in '68, Ford copied Chevy and built their own production 302 for the same reason.

and there are more reasons to build a 302 Chevy than just the need to fit into a certain rule package- the 4" bore and 3" stroke with a solid lifter cam was a recipe for some high rpm power shifting fun. a 327 or 350 will make more power, but the 301/302 will rev to the moon- and who doesn't like the sound of a V8 wound out to 8000+ rpm?

as already said, there is another way to build a 302 Chev using all factory parts- one that i want to do some day. you get the crank and rods from a 94-96 L99 powered Caprice and put it in an 87 and newer 350 block. the L99 is a 4.3 liter (262) V8 that looks externally identical to the 5.7 liter (350)LT1 engine, but has the smaller bore of a 305 (3.736") and a 3.00" stroke crank with longer 5.94" rods (compared to every other small block built since 55 that had 5.7" rods). the longer rods allow the use of standard replacement 350 pistons in a 4.00" bore block.

my goal is to build that 94 Caprice LT1 on the engine stand in the garage into a 302 with a big roller cam and put it in something light with insane gearing and a manual trans.. i know the LT1 has more potential with the stock crank and he more displacement it brings, but that's not the point here..

In reply to novaderrik:

Short stroke does not equal high RPM! Nothing about a 302 enables it to rev higher than a 350 but the cylinder heads and cam.

Low displacement typically needs a higher RPM to make power

to novaderrik: you forgot about the 400 SBC and its 5.565" rod length.

to tuna55: unless you're talking specifically about valve float as the rev limiter, i'm gonna have to say you're mistaken re. nothing about a 302 enabling it to rev higher than a 350. specifically, because the stroke is shorter, the crank / rods / pistons see lower accelerations and therefore will survive to higher RPM before destruction, assuming identical metallurgies between the two displacements. also, because of the smaller cylinder volume of the 302, it will indeed be able to spin a higher RPM than a 350 with the identical heads and cam before it runs out of airflow through the intake or exhaust.

Also (to the OP) if your intent is a high-revving small-block, don't even consider using the stock thirdgen TPI stuff. Not a bad intake setup for its time, and it looks cool, but the runner length is obscenely long and caps airflow much over 4500-5000 rpm.

Flynlow wrote: Also (to the OP) if your intent is a high-revving small-block, don't even consider using the stock thirdgen TPI stuff. Not a bad intake setup for its time, and it looks cool, but the runner length is obscenely long and caps airflow much over 4500-5000 rpm.

+1. A stock type TPI is a good truck intake, but the TPI motors didn't like to rev at all.

AngryCorvair wrote: to novaderrik: you forgot about the 400 SBC and its 5.565" rod length. to tuna55: unless you're talking specifically about valve float as the rev limiter, i'm gonna have to say you're mistaken re. nothing about a 302 enabling it to rev higher than a 350. specifically, because the stroke is shorter, the crank / rods / pistons see lower accelerations and therefore will survive to higher RPM before destruction, assuming identical metallurgies between the two displacements. also, because of the smaller cylinder volume of the 302, it will indeed be able to spin a higher RPM than a 350 with the identical heads and cam before it runs out of airflow through the intake or exhaust.

yeah, i always forget about the short 400 rods since no one ever uses them any more.

AngryCorvair wrote: to novaderrik: you forgot about the 400 SBC and its 5.565" rod length. to tuna55: unless you're talking specifically about valve float as the rev limiter, i'm gonna have to say you're mistaken re. nothing about a 302 enabling it to rev higher than a 350. specifically, because the stroke is shorter, the crank / rods / pistons see lower accelerations and therefore will survive to higher RPM before destruction, assuming identical metallurgies between the two displacements. also, because of the smaller cylinder volume of the 302, it will indeed be able to spin a higher RPM than a 350 with the identical heads and cam before it runs out of airflow through the intake or exhaust.

There are super stock cars out there running north of 9K RPM. The problems with RPM are not primarily bottom end related (although you are technically right) they are top end related.

Plus, the smaller engine takes less air at a given RPM because it's making less power, not because it gains the magic ability to make more power with less air.

tuna55 wrote: Just remember guys, those guys didn't build small engines because they were better, the 302 was created because of the rules. Cubes rule with the cylinder heads and metallurgy we have today. I would never build a 302 when I could build a 327 or 350 or 400 for nearly the same money.

Amen, tuna.

The only time I recommend smaller cubes is if you need to conform to the rules.

That being said, you don't need some exotic, fancy $700 assembly to make it. I bought a marine vortec 350 with a leaking head gasket for $50, complete carb to pan. Its only a crank, rods, and pistons away from being a 302, and the vortec heads will beat the flow of ANY other production head by 50% with about the same port volume.

But I wouldn't build a 302 unless you needed a DZ for a restoration. Forged stroker cranks are available for SBCs for dirt cheap, and you can build a 383 that can rev to 7000 RPMs, make 500 hp, and still make enough vacuum to run power brakes.

More cubes at the same RPM means potentially more HP and crazy gobs more torque, and the torque will happen at a far more streetable RPM.

A 500 hp 302 will idle at 1200, make peak torque at 5500 rpm, and require serious gearing, stall, and revs to make it work. A 500 hp 383 will idle at 800, make peak torque at 3500 rpm, and easily work on the street with a 2500 stall and 3.73 gears.

curtis73 wrote:

tuna55 wrote: Just remember guys, those guys didn't build small engines because they were better, the 302 was created because of the rules. Cubes rule with the cylinder heads and metallurgy we have today. I would never build a 302 when I could build a 327 or 350 or 400 for nearly the same money.

Amen, tuna. The only time I recommend smaller cubes is if you need to conform to the rules. That being said, you don't need some exotic, fancy $700 assembly to make it. I bought a marine vortec 350 with a leaking head gasket for $50, complete carb to pan. Its only a crank, rods, and pistons away from being a 302, and the vortec heads will beat the flow of ANY other production head by 50% with about the same port volume. But I wouldn't build a 302 unless you needed a DZ for a restoration. Forged stroker cranks are available for SBCs for dirt cheap, and you can build a 383 that can rev to 7000 RPMs, make 500 hp, and still make enough vacuum to run power brakes. More cubes at the same RPM means potentially more HP and crazy gobs more torque, and the torque will happen at a far more streetable RPM. A 500 hp 302 will idle at 1200, make peak torque at 5500 rpm, and require serious gearing, stall, and revs to make it work. A 500 hp 383 will idle at 800, make peak torque at 3500 rpm, and easily work on the street with a 2500 stall and 3.73 gears.

what is this "stall" thing you speak of? people that build small inch, high revving engines don't know or care about that word..

tuna55 wrote: Plus, the smaller engine takes less air at a given RPM because it's making less power, not because it gains the magic ability to make more power with less air.

no, the smaller engine takes less air at a given RPM because it is smaller.

I'm looking at building a 500+hp 302 for my C-Prepared car. The smaller motor allows the car to be lighter, which is a huge advantage in autocross.

I know it will be spendy, but I'm having a hard time determining the right way to go. For those who have gone this route, what do you recommend?

Open the catalog and pretend you have room on the credit card. Goals are under 310ci, 500+hp, and as reliable as a race car can be. Race gas is allowed.

Gimp wrote: I'm looking at building a 500+hp 302 for my C-Prepared car. The smaller motor allows the car to be lighter, which is a huge advantage in autocross.

A 302 weighs almost exactly the same as a 383... or a 400... or a 434 SBC for that matter. Same block, the only weight savings is the crank, but when you're talking about the difference between 565 and 575 lbs it won't really help.

... or are you saying that class rules allow for a lighter weight car?

Gimp wrote: I'm looking at building a 500+hp 302 for my C-Prepared car. The smaller motor allows the car to be lighter, which is a huge advantage in autocross.

No, no it does not. A stroker crank might weight slightly more than a regular crank, but for every increase in bore you're removing steel and adding aluminum. This is just flat out false.