Does anyone have a 302 chev or a hi-po 283 in Z?

[Guest butlersZ]

and if so , whats the hp/tq numbers ? I have a 283 block and am considering boring it out to a 302. Need to know how much power they put out.

[Guest Nic-Rebel450CA]

how much power do you want? if you want it, there is a way to get it.

[jt1]

A 302 is 4" bore x 3" stroke, which means boring the 283 0.125" over, and that isn't going to happen. Very few 283 blocks will take a 60 bore without the cylinder walls getting too thin. If you want a 302, find a small journal 327 block and use your 283 crank. 302's can make good hp #'s, but they have to turn a lot of rpm to do it, like 7500 - 8000, and that's hard on the bottom end. You can make the same power and get a lot more durability with more cubic inches.

 

John

[Guest butlersZ]

well now that I know that the 283 can't be bored to a 302, now I want a 327. Although how hard is it to get around 300-325 HP from a 283? I know in the older vettes with the 283 there was a 290 HP version that was fuel injected. I would think that with the newer technology 300 HP would be of ease, am I right? My 283 is a '64 replacement block made with the 327 tooling(the dish in the bottom of the cylinders).

[jt1]

A 300 hp 283 would be no problem at all, especially with modern heads. With the 283 power pack heads you would need to spend a good bit of money on porting; better to just buy some more modern heads. Smokey Yunick built a 450 hp 302 back in the early 70's, with a fabricated cross ram intake that was the prototype for the "Smokeram" intake Edelbrock made for the Trans Am cars. 302's can run, no doubt about it. They made the Z28's legends, but they have to turn a lot of rpm to do it.

 

John

[Guest butlersZ]

Well then what if I went with some trickflow 23 deg. heads (if I can afford it) or maybe some Vortecs and port them out as well? This old hotrodder I know said that the power is all in the heads. I believe that after porting my E88 on my '74Z. Huge difference. I am planning to go along with roller rockers and roller lifters to cut down on the friction at those high rpm's, I'll do the port work on the heads myself( I have done many). I have never built a small block before though and just aquired a new project car that was previously set up for a 350. I just can't decide which motor to put in, 283(already have most of the parts needed), 302, or a 327. I really want to go 302, nobody I know has it yet in a Z. The pistons are really expensive though and that was why I was considering the 283 a candidate. With a reasonable budget, how much power can they built up though? My minimum goal is 300Hp and 275 Tq. Any suggestions for a good combo?

[Guest Nic-Rebel450CA]

My minimum goal is 300Hp and 275 Tq. Any

suggestions for a good combo?

 

You can make this with stock heads' date=' a good intake and good fuel delivery (carb or FI) and a good exhaust. If you have found dyno graphs of 305 (the "5.0" Chevy engine) you will see that they arent real powerhouses. Dont get this confused in any way with the 302. A warmed 302 can easily make 300 HP and well before 6000 RPM.

 

 

I really want to go 302, nobody I know has it yet in a Z.

I might beat you to it

Maybe would could compare notes

[Guest butlersZ]

well, we'll see who swaps it in first. The only trouble I'm having is finding out which combo makes what with the 283 and 302. But also while staying on a somewhat limited budget and also not taking years to do it. The car is already set up, it's just the motor and maybe the tranny a little bit too, probably a th-350 though. But a T56 would be nice huh?

[Guest Nic-Rebel450CA]

But a T56 would be nice huh?

 

Oh yeah, especially with a 302. I cant wait to pound through the gears in those high RPMS

 

A 283 and a 302 are very different animals. A 283 will have less power in general, but will still rev like the 302, maybe even a little better. A 327 will have more bottom end, as will a 350. If you build them up good ($) then any small block Chevy can rev very high, I have just been leaning a little more towards a 302 because it will be easier to get that to sip gas when I am not punching it as opposed to a 350. Of course, after I check out Heavy Z's 327 in person I might sway towards a 327

[Guest butlersZ]

Well when you go for a ride in it, let me know how it is, I'm stuck on the 302 myself, like I said earlier, no one has it yet. I like to be unique, don't want my friends to copy me anymore, one guy is in the process with duplicating my '74 with the L28, same coil,wires,block,carbs, everything. But with the SBC swap, theres no chance. I want a demon carb too. Of course, everybody has thier dream setup

[Brad-ManQ45]

Why not use the 350 pistons and go with a longer rod? You DO want good rods don't you?

 

Grumpy - is there a reason this shouldn't be done?

 

IJWTK...

[Heavy Z]

Hey Butler, you want something your friends won't have? DavyZ posted this a while ago, it's a 400 block w/ a 327 crank, long rods, 54cc 305 heads, and 11:1 compression that'll run fine on 87 octane:

 

http://www.airflowresearch.com/articles/article03/A3-P1.htm

[QWKDTSN]

11:1 compression that'll run fine on 87 octane

 

[Guest MKIII91t]

http://www.airflowresearch.com/articles/article03/A3-P1.htm

 

i've seen that link before. do you think you could spray nitrous on a motor with that much compression? if so, how big of a shot can you go? 150 would be plenty, 175 would be good too.

[DavyZ]

http://www.airflowresearch.com/articles/article03/A3-P1.htm

 

i've seen that link before. do you think you could spray nitrous on a motor with that much compression? if so' date=' how big of a shot can you go? 150 would be plenty, 175 would be good too.[/quote']

 

Not sure---I've never done spray before, but I venture to say (from what I have read) that it depends more on timing then it does on compression. What I find so intriguing about that article is the amount of compression they can run simply because they have good quench.

 

What I really want to know is this: if you can run that setup on 87 octane, can you also run 12:1 or 13:1 compression using 92 octane?? That would possibly put a few more ponies under the hood. Man, what a sick motor that would be. Understand that I will not put anything less then 91/92 octane into a performance car with a V8. Hmmm.

 

Davy

[Heavy Z]

Man Davy, that's a good question. It sounds reasonable to me that you could squeeze an extra point or two of compression if you ran 91. That would be quite a motor.

[Guest shortyz]

uhm.. i got a 302 in a 1971 Z...

 

so u wont be the first heheheheheh 8)

 

it pulls hard and sideways up to 7 grand.. havent pushed it farther.

 

my bro bought it for 7 grand cdn, so its still in the family (i made sure so i could keep driving it )

[Guest butlersZ]

Bastard!

[Guest butlersZ]

Bastard!

[Guest shortyz]