what pistons do i buy for a DZ302, gonna build one for my 84 Z, thought it would be cool to make it kind of like the old style 69Z28s, except im gonna be pumping out about 450-500hp out of mine

 

if you have a dz block sell it to someone that needs it. there isn't really anything magical about it. it's just like any other 4 bolt 4" bore LJ SBC block. i always find it funny everyone has a DZ block but never a CNA casting. the pistons you buy depend on your intended application which you negelected to mention. you'll be money and power ahead to build a 350, might not be as cool as spending more money for less inches and less power but you'd be ahead in the long run.

 

well i wanted to make a 302, not a 350, i have a 350 right now, but i also wanted to be able to have the rpm range of the short stroke 302, otherwise i wanted to build a 383
so what i wanted to do was build a 302ci small block, not a 350 out of a DZ302

and also it is a real DZ302 block, the VIN in front of where the cyl head mounts says V060DZ or somethin real close to that, i would have to go look to get the exact number

 

RPM range is more dependent on the valvetrain and the heads/intake combo you match to it.

If you are going above 6500rpm's though, a stroke between 3-3.48 is the way to go. To gain an optimum rod ratio with a 3 inch stroke for a nice powerband however it places the wrist pin low in the piston and makes the piston heavy. With the 3.25" stroke you can obtain the best rod ratio for high rpm power. 3.48" is on the high side, however it still produces significant power in higher rpm operation.

Remember though, for every increase in stroke there is an increase in low speed torque but not a linear increase in output.

 

I think ede is saying that a numbers matching 302 block is worth a fortune to a person doing a 69 Z28. Sell it to someone who needs it for such a project and just get a 4 inch bore block to make your 302 with.

They were only around for three short years. In fact, in 1967 there were only about 600 Z28s made and around 20,000 in 1969. Thus you can see that GENUINE blocks are very hard for a restorer to get.

You'll be doing the Camaro fraternity a real service to help out with a genuine 302 block in such a way.

 

yep that's what i'm saying. if you want to spend your money on bullets to shoot yourself in the foot with (more money for less power) build the 302. hell i've done the same thing, just because i wanted to do something differant. the fact is if you have a original gm 302 block. crank. carb ,or anything else advertise it in hemmings and you'll get more than enough money to finiance building a 302 from top of the line aftermarket parts and someoen will have a numbers matching z/28. the matching numbers doesn't mean anyyou and it means a lot to someone restoring a z/28.

 

you can get original spec 302 pistons for .030 over blocks and 11.0:1 compression in the gm performance parts book
p/n 3946882. i have a 1967 dz302 steel crank sittin in a bag in my garage that still has standard size journals.....but it is a small journal crank. i say go for it if you want to build it. a guy i work with had a 69 z28 that he made run 10's N/A with a 302 and a 4 speed. of course he had to run a 5.86 gear and was shifting at 10,000 rpm. if you want a real screamer i'd build a 377. stick a 350 crank in a 400 block with bearing spacers. i've seen those things turn almost 11,000 rpm when done right.

 

fast there were no dz castings, or forgings in 67 and i beleive they were all lj

 

I'd have to agree.....

 

well then let me go get the casting nuber off of it because it is a forged steel, small journal 3" stroke crank...............ok here it is:
3735236

 

and if i remember right the large journal blocks didn't come in to play until 1969. i thought the 67-68 302's were still the small journal.

 

you have a 283 crank, 3" SJ forged steel, i've got a couple just like it. the 302 was the first LJ engine, or block gm made. not 100% sure but i tihnk 67s were 2 bolt, but with only 600 made and no z/28 badges there aren't many if any left around.

 

GM's whole lineup was large journal by the 1968 model year. The first large journal block (only one) was the 67 350 in the Camaro.

67 Z/28 block was LJ 2 bolt small journal crank
68-69 Z/28 block was DZ 4 bolt large journal cranks

 

the camaro didn't get the 350 until 1969 when it pretty much replaced the 327 all together.

 

Actually it did get a 350 in 1967. It came in some of the SS and was called the L48 and it made 295HP. See here.... http://www.camaros.org/diffs67.shtml

David

 

my dad had a '67 RS/SS wich came with a stock 350.

 

The original 1967 350s had problems with their crankshafts, if I recall correctly.