[Sureguy]

I am going to be either rebuilding my 327 or putting a different motor in my '68 until I have the time and $$$$ to build my dream motor. I am looking into building a 302 because of the durability and decent gas mileage(EFI) of a smaller motor. Is there any reason I shouldn't build a 302? Also how hard is it to find a 283 crank and what needs to be done to convert my 327 to a 302? What modifications or additions should be done while biulding the motor to make better, stronger, faster?

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<BLOCKQUOTE>quote:</font><HR>
The night-time is the right time

****James Bondo****
<HR></BLOCKQUOTE>

[68SS396]

Just my opinion but making a 302 doesn't mean your going to have this high revving copy of a Z motor. Just like a 70 350 LT1 Corvette motor isn't the same as a Impala 350. You said you are looking into a 302 because of durability. A 302 is durable because of the parts that went into it, not because its a 302. I would redo the 327 you have. Any parts you would buy to make a durable 302 would make the 327 just as durable, without all the extra machine work$$$. I know you want smaller right now but the same parts that you would put into a 302 to make a 302 would make more power in the 327. There's no substitute for cubic inches. Did anyone ever say that before, sounds familiar. Maybe when you get into a real high revving race motor situation where things like stroke vs bore and conecting rod length etc come into play the 302 might be better. But probably not for what you want right now. Remember, Chevrolet didn't make the 302 because its the best motor combination out there, they did it because the cubic inch limit at the time (racing) was 305 and the 302 could be made with off the shelf parts (money saver). Don't remember what the limit was changed to in 70 (I think 360) but GM didn't keep the 302 and moved to a 350, closer to the limit. Back to that cubic inch thing. Sorry so long and I always wanted a 302, but not to build when I don't own the Z to go with it. Just my opinion. Besides nothing is worse than having a non Chevy guy tell you that your a idiot because Chevy never made a 302 and the early Z's came with 350's std and big block optional. Had to throw that in because I overheard a spectator telling a Z owner this at a swap meet last season

[Dave Birdwell]

Advantages of the 302...
Will spin to 8000 rpm with no problem(if balanced and good rods, pistons, and bolts)

Disadvantages...
Special pistons, only two available, $5-600 a set...
needs to spin to 8000 to make any power...
no low end torque...
eats clutches for lunch, unless you run 4.10 or lower rear gears...
mileage is not any better than a comparable 350...
constantly spinning engine above 4000 in-town cruising to get car to move smoothly...
really has to have a 4-speed trans(see also-no low end torque)...
etc.etc.etc...
If I were to buy another Z, I would pull the 302, and change the shortblock to a 350 and use the same heads and valve covers, no one can tell the difference by looking. It will make it 500% easier to drive, also.

[Shawn]

I thinks Dave is right. Everybody seems to like the Mystique and Aura of the 302. Who doesn't like the idea of a wicked small block that screams up to 8000 RPM? But, don't forget GM never intended this to be anything but a holmogated race motor. It's a great and essential centerpiece for any Z, but like Dave said, if you really want to drive the thing, pull the engine. Stuff something more street friendly in it's place. Pack it nicely in the corner with lots of lube and leave it there to be re-united with the car some other day. Which begs the question, do you really want to build a very expensive CLONE motor that isn't all that "streetable" to begin with?

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Shawn Peterson
1969 Z28, 406SB


[This message has been edited by Shawn (edited 12-17-99).]

[davidpozzi]

the 67 thru 69 302 had a 4" bore and a 3" stroke. Your 327 has a 4" bore and a 3.25" stroke. A 350 has a 4"bore and a 3.48 stroke.

An 80's 305 used a 3.48 stroke and a smaller bore. Somewhere around the mid 80's they went to a one piece rear seal and EXTERNAL balancing. The 302 developed nearly the same torque as a similar year 350 but less hp. I had an 85 302 with tuned port injection- 0 to 60 was about 7 seconds. My 89 350 Iroc was about 6 seconds.

Get a target 350 from chevy and put a mild cam in it. These engines run great, make good power, and are guaranteed for 50,000. miles.They usually cost less than a properly done rebuilt engine. The cam they come with is not bad, similar to a non smog 60's cam.

The best thing about a 350 is the torque. When you hit the gas it'll go right now, at any rpm. The 302 (67-69 type) has to rev up to make power. They would come on at 4500 rpm and the ignition (points) would break up at 6000 to 6500 rpm. the 302 needs low gears to work at all.

In 1969 I raced a 68 Z/28 with my 67 275hp 327 with 4 speed and 3.08 gears. we were about even, If I'd had the 3.73 gears he had I would have left him in the dust! I think all I had done to my car was re-curve the distributor. Later, I installed a 325 horse hydraulic cam. I still got good mileage and the car ran good.

[DjD]

David - Was the 302 below a typo?
<BLOCKQUOTE>quote:</font><HR>Originally posted by davidpozzi:
An 80's 305 used a 3.48 stroke and a smaller bore. Somewhere around the mid 80's they went to a one piece rear seal and EXTERNAL balancing. The 302 developed nearly the same torque as a similar year 350 but less hp. I had an 85 302 with tuned port injection- 0 to 60 was about 7 seconds. My 89 350 Iroc was about 6 seconds.<HR></BLOCKQUOTE>

Back in '74-'75 my buddy's stock '68 302 Z28 saw 8,000 rpm all the time! No problems with his points...
<BLOCKQUOTE>quote:</font><HR>
The 302 (67-69 type) has to rev up to make power. They would come on at 4500 rpm and the ignition (points) would break up at 6000 to 6500 rpm. the 302 needs low gears to work at all.<HR></BLOCKQUOTE>

If the guy in the Z's driving skills were equal to yours (IMO) you would have been looking at his tail pipes!
<BLOCKQUOTE>quote:</font><HR>
In 1969 I raced a 68 Z/28 with my 67 275hp 327 with 4 speed and 3.08 gears. we were about even, If I'd had the 3.73 gears he had I would have left him in the dust! I think all I had done to my car was re-curve the distributor. Later, I installed a 325 horse hydraulic cam. I still got good mileage and the car ran good.<HR></BLOCKQUOTE>

I agree a 350 would make a more streetable choice and personally would leave the 302's to the Z28's....

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...DjD
69RS Ragtop
www.fbody.com/members/topless69

[clill]

I vote for the 350. I have several Z28's and you have to do alot to them to make em move like you want. Yes they sound great but people read too much legendary stuff in the magazines. You could build a 350 and call it a 302.= sleeper.

[davidpozzi]

I did make a typo in my origonal post. Here is the corrected version.

An 80's 305 used a 3.48 stroke and a smaller bore. Somewhere around the mid 80's they went to a one piece rear seal and EXTERNAL balancing. The 305 developed nearly the same torque as a similar year 350 but less hp. I had an 85 305 with tuned port injection- 0 to 60 was about 7 seconds. My 89 350 Iroc was about 6 seconds.

I would expect the valves to float with a stock 67-69 302 turning 8000rpm using factory springs.

The 68 Z/28 I raced had an advantage over me. I had the 4 speed saginaw trans and you cant shift them fast at all! But he may not have been revving it like he should have. I had a friend with a 69 302 with 4:10 gears and headers that would have run away from me. But I think a lot of totally stock 302's with a fiew miles on a tune up would be a close race for a 327 with equal gearing and a little sharp tuning.

[Eman]

327-cid Chevrolet block with a 283-cid Chevrolet crankshaft for a 4" x 3" stroke that yielded 302.3 cubic inches. I have a 283 engine in my camaro. I'm looking for a 396.

[clill]

I had a 69 RS Z28 with 95000 miles on it, engine had never been apart. I added a Crossram and Chambered exhaust. It would wind to 8000 easily. I kept thinking something would come apart, finally changed out the orig. Nylon timing gears and chain. It was a slug off the line but once it got going it was fun.

[davidpozzi]

<BLOCKQUOTE>quote:</font><HR>Originally posted by clill:
I had a 69 RS Z28 with 95000 miles on it, engine had never been apart. I added a Crossram and Chambered exhaust. It would wind to 8000 easily. I kept thinking something would come apart, finally changed out the orig. Nylon timing gears and chain. It was a slug off the line but once it got going it was fun.<HR></BLOCKQUOTE>

I've seen other guy's 302's shed the timing chain at 75000 miles. The plastic teeth go. Say, how did the crossram do? I've read that the crossram actually helps the engine develop more upper midrange torque. Did you notice any improvement around 4500?

[clill]

That's exactly why I changed the chain and gears out. I new I was on borrowed time with them. 4500 is about exactly where it started to make real power, and kept pulling all the way through 8000. Just kept hopeing stuff would never fly through the hood. The guy I sold the car to still has it and the engine has still never been apart.

[Doug Garland]

Everybody wants a 302, I know a guy about 25minutes from me that has several for sale.I looked at 3 he had down at the Moultrie , Ga. swap meet back around Thanksgiving. There were 2 '68 models, and a '69.
I have access to a complete DZ bottom end, it has been put in a '71 350 block.The original block didn't make it.It has the #1178 crank, pink rods, pop-ups.Also a couple of sets of heads, and several intakes are available. Anyone seen an O.T.C. intake for a 302, it has a different casting # from the others I have seen, I think it was a #116.If anyone needs parts, email me, I'll give you a price, and all the casting #'s info.

[This message has been edited by Doug Garland (edited 12-30-1999).]

[69z28rsMATCH#s]

Yo,

I would go 302! It's really not a matter of cubic inches cause Chevy squeezed more horses out of the 302 compared to the 350 or 327. They underated ti at 290 so they could get in the TA races. That's why it say " 290" but in DYNO tests it shows more like 426. Now you can squeeze whatever you want out of most anything but this was really cool if you think about it. 400+ horses out of the small 302 ( thought to be a Ford engine by all NON-Camaro people). Z28s are amazing cars mine is awesome I only wish that i could have more drive time with it. http://www.69zee.homestead.com/enter.html check her out! Nice car. Well follow your heart is all I can say to you. Mine says 302 seeing the awesome power. But follow your own. C ya later!

Cya!

69Z

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69 Z28 RS. ORIGINAL window sticker. GM documentation from work being done. Replacement P.O.P from early 69. Fresh off RESTO. 500 miles since put on. NICE car! EMAIL me for PICS!

69Z (nike10622@msn.com)

[ScottB]

Regarding the 302 gas milage.
&gt;&gt;I am looking into building a 302 because of the durability and decent gas mileage(EFI) of a smaller motor.&lt;&lt;
My 69 Z/28 with 3.73 gears makes my 86 3/4 ton Suburban with a 454 seem fuel efficient. If you keep your foot out of it(impossible for me to do)you might get 6 - 8 mpg on the freeway. On city streets you spend most of the time in 2nd and 3rd only get into 4th over 50mph. My 302 is alot of fun , but I wouldn't build a 302 if it's not a real Z/28.