Can you build a real Chevy 302?

your right I have a dz camero block sitting in my garage...it is stamped DZ

 

DZ is 69. 67-8 were MO's and some MP's I think. It's been a while, but I used to be around those a lot

 

I'd like to try at building one that starts making torque @ a lower RPM. I think it can be done.

 

Any time you try to make more power in the lower rpm, you loose power in the top rpm. You can't have both. decide what you want it to do(what max rpm? street driver or all out race car) and then pick compression ratio and cam size, intake, ect. btw 377 cid likes rpm's to 9000.

 

I am always dismayed at the concern over 4 bolt mains versus 2 bolt mains ... I have raced a lot of Chevys and known a lot guys that raced Chevys back when all there were 2 bolt main blocks and I dont know of anyone that ever spun a main bearing. Rods sure but mains never.

 

2 bolt blocks are easier to find and have bigger webs. If you are really after strength you take a 2 bolt block and mate 4 bolt caps to it.

If you are going to build one to turn that many Rs it needs to be align bored and decked anyway so you only really loose the cost of the caps and paying someone to drill and tap the extra holes.

If you find a large journal 283 crank IE after '68 you can also build the mill with a 350 block. Far easier to find a pristine seasoned 350 block.

Personally I would prefer to build one with the small journal crank. It will handle the Rs better (less loading on the mains) but that would be next to impossible. Not too many clean small journal 327 blocks out there.

The real majic behind the 302 is the bore to stroke ratio. I don't think that it was by design but it is about the optimum bore to stroke ratio so it worked out well.

There is another trick or two for you fellas that prefer shorter stroke engines. if you will allow me the indulgence.

For instance you can build a 327 from a throw away 307 crank and a 350 block. 307 cores are cheap. Well up until I threw out there.

You can also take a large journal 327 crank and a 400 block bored .030 and come up with a short stroke 350. That was the engine that GM should have built instead of the 350 that they marketed.

Here is my take on it. Build it heavy on the bore side if the equation, keep the stroke as short as possible, and your compression as high as is tolerable. Mash the loud peddle and let it sing.

High rev cruising is a rush.

Well I hijacked the post.
Sorry 'bout that.

Carry on.

 

This is the formula that I've always used to calculate cubic inches:

Bore x bore x stroke x no. of cylinders x .7845 = cubic inches

Regarding the 302 versus 301 question:

4.000 x 4.000 x 3.000 x 8 x .7845 = 301.248 cubic inches


Buckshot40

 

Are you sure it's not .7854??? That'd make it 301.5936.
Larry T

 

You, sir are correct! Got my numbers crossed - my bad!

Buckshot40

 

.7854 would be correct.

 

I think most of the 302's were dogs on the bottom end because of the big overlap cams. I think the ford 302's use the 4" bore and 3" stroke. Someone correct me if I am wrong on this, Those seem to go pretty well in those late model cars, but it's just not a Chevy.

 

yeh before there were 327,s we just bored 283,s out 1/8. we called them 306,s ??? as far as i knew the old 283,s could take a 1/8 bore no problem. I bored my 265 to 283 at Jr. college shop, it was done all the time, we hadnt heard of thinwalls yet.

 

302's......easy to build 327 block and 283 Crank. As noted above.....a bazillion 327's & 283's were made and are all over the place. Al use 5.7 rods.....

LJ Opion - Use a 350 LJ Block and 283 SJ Crank...........can get spacer bearings to use little SJ crank in LJ block. They are sold on Speed Shops and EBAY too.
Not all 283's are steel...........cast too........easy to tell.
283 Steel work (round flywheel flange)
302 SJ has a (notch in the round flange)

Low buck Build..........find a 327 block with small ridge...cut out ridge and run loose....std bore pistoles are every where...I have 24 of the little ashtrays...

Short stroke and loose bores work just fine.....

 

Reving my 302 Crank 292" Aluminum Rod engine this morning....neat to see the 8K RPM Sun Tack Buried with no effort.

 

This one's a 305. The class was 307 and under.

It will do whatever you want. I guess they are not real 302's without the proper casting number.

 

Boy it sounds like time to get rid of the one I have.
It is a clone with a an original 302 large journal crank/ rods/ pistons.
I made it with a 3970010 block, And a smaller set of heads with 194 valves non accessory hole's with 194 valves, fully ported. A fully balanced assembly / rods side clearanced
Had it in a 70 Vega / chy 8/34 / 391 suregrip / 13 lb alum flywheel.
/ It would twist up too 8000 grand. The little car beat quit a few hemi cuds on telegraph rd in Mich in the 70s.

 

Good ol' U.S. 24.... My old stomping grounds back in the day.. Just keep an eye out for the Redford "boys in blue" They love writing out tickets.

 

Why build a 302, when you can do the same thing with a 400 block, and build a destroked 400 w/350 crank (aka 377) more cubes.. all the same revving fun!

Or you can do what I did w/my 383 which is build a "long rod" motor, which will correct the geometry of the 383 and allow you to rev it high.

 

It's just not the same......

 

The stroke on both of the motors is too long, the piston still has to travel an 1/2" or 3/4" further up and back down EVERY revolution therefore the 3" crank (265,283 or 302)WILL wind with less stress on the rods than any other factory small block chev. I read in an old magazine that a 409 turning 6k had something like 10,000lbs of force being applied to each of the rods twice EVERY Revolution, or something along that line

Here is something to ponder, 283's and 289's have similar cubes, but the 283 has a 3.875 bore and 3" stroke whereas the 289 has a 4" bore and a 2.875 stroke, and 302 fords and chevs are identical bore and stroke but you dont hear about the rev-ability of the SBF's as much as the chevs

 

Probably due to the rod length to stroke ratio.. I'll have to read up on the subject..

 

It has to do with piston speed and weight. The stock 409 pistons weighed a ton. Now you can get superlight pistons for just about any engine (including 409s), so piston speed isn't near as critical as it once was.
BTW, I used to run with a serious street racer back in the early 70's. He used to call Z-28's Zippers because of the way they sounded at 8,000 rpms. LOL
Larry T

 

the original 283 bored to 4.00 was called a 301 engine ... It was done simply because that was as far as you could take a good 283 block relatively cheaply. The 327 didnt appear before 1962. Stroker cranks back then cost more then a good complete engine. 348 engines were correctly called truck engines and didnt perform as well as a well built 283 that was worked. I had a really strong .060 over 292 cu in engine in a 55 Chevy that beat just about everything in town until 327's started showing up in wrecking yards in 63 ... by '68 when I got out of the army everything was big block ... Hell you could buy a low 13 second car off the show room floor and just take it to the track then.

 

My 292 Aluminum Rod Engine gets a full QTR thrashing this year. I beat the Sun 8K tack into submission yesterday morning.....that is with a 50LB steel flywheel.........
..No Aluminum Required.........let'n the nighbors know its SPRING again... I can tell you my 5:38 gear ain't enough.........bet I can run 3rd gear with 30" tires thru the QTR.

 

Looked at this many times
Better version 377, 400 block, 350 crank, same rpm's more cubes

302 were both small and large journals depending on year, so yes they were made fro 350 and 327 blocks.
Circle track guys like 2 bolt mains becuase they typically build 400's and the 400 4 bolts are weaker
Best bet is 2 bolt block with splayed mains easy conversion at machine shop, new main caps, line bore the engine
a "301" is an overbored 283 and was popular before guys moved up to 327's and 350's
turning 7000 rpms was a necessity when all you had were small engines it takes a much more costly / temprimental valvetrain to make it live and is hard on parts, not much reason to do it if you can get the same power from more cubes, if youre drag racing only - sure, if you want to drive around town the peaky high rpm cam, high compression is a pain the ass.

Build a 377 dress it out as an early 302 youll make more power down low and it will still turn 7K if you want to do it. any sbc can turn 7K, you need good valvetrain to do it regularly.

 

check out ebay on nacar cranks, small stroke aftermarket cranks with "honda" 1.88 rod journals are cheap, they are typically small journal so that turns off 350 block guys unless you want to run a spacer bearing.
that lets you run high quality 1.88 journal rods in whatever length you want, they go cheap because no one except race teams are running the 1.88 rod journal
you can put together a sbc out of used nascar parts that will take much more abuse than 40 yr old factory stuff.
Bryant crank, Oliver rods 6-6.125 in, J&E pistons - you need a small journal 327 block or a 350 / 400 with spacer bearings,

 

Honda parts in my motors????......... Ummm I don't think so!

 

I don't know. My Anglia (running a 327) was turning 8000 through the traps in 4th with 5.38's and 28" tall slicks. That was mid 11s @ 120mph.
Larry T

 

Hey Larry. Got more pics of your avatar?? Please post'em if you got'em. Thanks bud!

 

Deuces,
It's just mocked up right now. I've got 3 different intakes to play with when I get my Anglia going again, this is one of them. It's an Offy, not a GM. That's probably not gonna happen very soon since I'm working on the 55 right now, not the Anglia.
Larry T