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302 building info


Guest Nic-Rebel450CA

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Guest Nic-Rebel450CA

I am preparing to start building my engine for my Z, I just need some info from those who know all the good stuff about engine blocks.

 

I am looking for a 327 block, and I am wondering if any particular years are better to go for. Better metal composition, etc. I am under the impression that Chevy never made a 4-bolt main 327, is this correct? Are all 327's small journal?

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There were no 4 bolt 327's. 68's were the last year of the 327 and were large journal motors. All previous were small journal. All the small journal motors I've seen are forged crank motors, and I've read all small journal motors had forged cranks.

 

You can build a 4 bolt 327 if you want, use a 4 bolt 350 block and a large journal 3.25 stroke crank. An original one will be hard to find, 68 only, but the aftermarket ones are fine.

 

There's nothing wrong with a small journal 327. Lighter rotating assembly and less friction. Upgrade the rods, balance it a have a real winder.

 

John

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Guest Nic-Rebel450CA

I am actually planning to build a 302, I just want to make sure that the 283 crank can go into any 327 block I find, and that the block is a good block.

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I would find a small journal 327, and use aluminum heads.

arp bolts on the bottom end should be good enough to keep it together

camel hump heads had the 2.02/1.6 valve in them, flow good for the time but nothing compared to todays heads, alloy or cast, i like alloy though and would love to build a v8 with alloy heads.

small journal is up to 67,

concentration would be balancing the forged assembly.

you gotta love the stock forged bottom end on those.

my old z had a 327, and it used to belong to the same guy who owned your 70 before you!!!

mine was mildly put together with 300rwhp or so, and made awesome power from 2500-6200rpm, bottom end solid as a rock, with nitrous!

good luck on the 327, its my favorite chevy motor just because it has a nice ring to it, look at my name!!!

build it up well, you could see 7k or more, and that would be fun.

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Guest Nic-Rebel450CA

I plan to use a forged 283 crank, 6" rods (if possible), and was thinking of vortec heads. I want to try to get about 12:1 or 13:1 compression but want to plan on the fact that later on down the road I will probably add on a supercharger. This will be my first engine that I have ever built, but I will have some help from others who have built engines before. I am very open to any suggestions, the only thing I am married to is using this crank.

 

For now I want about 325 rwhp out of the 302.

 

My most important question though is just wondering if any particular 327 block is better. I have heard that the V8's were made with different compositions of metals throughout the years and some are better than others. I am also curious if this crank could fit into any later model blocks. I dont think it would be able to, but I dont know much about the engines after Gen. I.

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Guest storm280z

im new to the whole v8 world but im planning to built my first v8 280z soon. an im goin to use a 350ci motor. is there any reason your using a 327 over the 350.

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To use a 283 crank in a 327 block to make a destroked 302, you will need to use the early small journal 327 block.

On the other hand... IF you want to make a large journal 327, you should use any year 350 block and a 327 large journal crank, OR the cheaper option would be to use a 307 crank. They are not widely recognized as having the same stroke as well as rod and main journal dimensions as the 327.

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Guest Nic-Rebel450CA
im new to the whole v8 world but im planning to built my first v8 280z soon. an im goin to use a 350ci motor. is there any reason your using a 327 over the 350.

 

I am not building a 327, I am building a 302. By putting a 283 crank in a 327 block I will have a 302ci engine. I have several reasons for wanting to build a 302, but none of them are really worth considering for the average builder. Most people just want as much HP as possible out of a V8, obviously going for smaller displacement will not get the most HP. I am not trying to get a ton of HP, I am building the 302 mostly for exotic appeal.

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Nic, as far as I know all small journal 327 blocks are equal. The high nickel stuff didn't come along till the very late 60's and early 70's. To use your 283 crank you will want a pre 68 block.

 

A 283 crank and a small journal 327 block will make a dandy 302. I used to race a dirt late model with that exact combo.

 

John

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Guest Nic-Rebel450CA

Maybe I will just go that route. I already have a 350 engine from an 88 truck and may even be a 4-bolt. I could probably sell the 350 crank for a few bucks, or hold onto it in case I decide to go to 350 in the future.

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That 88 350 engine you have won`t be of much use in this situation. 86 and newer sbc`s have one piece rear main seals where your 283 crank uses a 2 piece seal. You will need to find an earlier 350 block.

 

A good note is that you should be able to get some decent cash for the 350. Probably enough to buy an earlier block, and still have some cash for machining and misc left over.

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Guest Nic-Rebel450CA

Ya, the 350 has a mild cam, an Edelbrock intake, and some good flowing heads. I kinda dont want to see it go, it sure can move! Not what I am looking for for my Z though.

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  • 4 weeks later...
Guest Nic-Rebel450CA

Well, it looks like I am going to have some more time to think about engine build up for my Z, so I decided to go back to this topic.

 

Now, I was planning on going with the 350 block with bearing spacers and a 283 crank, but when I was searching for bearing spacers on the internet, I found another forum where someone mentioned the same idea I had about putting the crank from the 4.3L Caprice into an LT1 block.

 

Here are some specs that he mentioned about the 4.3 and the LT1:

 

CID....Years....Bore.....Stroke....Main....Rod....Mainbearing

265...L99-94...3.740......3.00....2.45...2.10....4.32

350...LT1-92...4.000......3.48....2.45...2.10....5.73

 

Now, I dont know much about what the numbers mean, can anyone confirm if the L99 crank can be used in the LT1 block?

 

Also, if I were to go that route, what pistons would I use? I was reading that you have to use pistons other than 350 pistons because of where the wristpin is (or something like that).

 

Anyone have any advice as to which would be a better way to go? (350 with bearing spacers and a 283 crank vs LT1 with L99 crank)

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Guest Nic-Rebel450CA
I have a complete 4.3 LT1 if you like.

Tim

 

How much? I would really like to go with a 302 because of the bigger bore and the ability to use normal sized heads with nice big valves, however, the 4.3 is looking a little attractive being that it will take much less work and $$ as it is already a complete engine. I guess I would just have to supercharge it then :twisted:

 

Know where I can find any stock specs for the L99?

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