My 85' 5.0L IROC Z28 is rated 170hp stock mine, ain't stock so I'll say 180Hp.
The stock 3.4 has 160hp, add the huge cam and the better flowing 2.8/3.1 type plentum and short duel exhaust and I got to at least be pushing 180Hp.
I am about to (to night) order a 3.4 from crate-engines.com and I want to have the cam swaped out before I put it in.
I want a crane cam H-272-2
dur@ .05'' lift
in 216* .454''
out 228* .480''
with 112* lobe seperation
I might also get bord one day and put 1.6 rockers in it.
I'm useing the old 2.8 manifold with eather 17lb.hr or 22lb.hr injectors I'll start with the 3.4injectors but want to try 22lb.hr. injectors some time on it.
When I come home and get reunited with the car I'll have ported cylinder heads and ported and done up intake manifold and plentum to add on.
The car is a 5 speed with GM one wheel squeel 3.42 rear gears.
Do you think that cam might be a little much?
Any one have any ideas?

 

Well look at some of the 3rd gens one of the 3 5.0 s available in 85' Z-28 (not with the IROC package) had 165 hp. A 3.4 has 160 hp factory give it an intake and an exhaust its got the Z-28 beat. Take an older 3rd the 3.4 beats them stock in the hp department.

Now if you made a 3.4 capable of nailing a 4th gen Z-28 that would be a hell of a proud day.

"theres no replacement for displacement"

 

What about the torque curve of the V8 vs. your 3.4L? If I was a betting man, Id say the V8 probably made more torque sooner and flatter than your 3.4L does.

 

my moneys with bigsteve7 on the torque curve.

 

The torque curve on that 5.0L goes some like this, up kind fo sharply to about 260-270 ft.lb before 3800rpms then rather quickly tapering off through out the rpm scale.
The V6 would get crushed in the torque department.
The 3.4 stock has about 205 ft.lb I don't think with that cam it would push much over 220ft/lb and and no way it would go over 240 and it would move the curve higher up on the scale to peak around 4200 then kind of slowy decline out to 6000 at the most I'm guessing.
My Z28 would crush the V6 off the line compairing torque but the V6 is about 300lb lighter, I think it would still get crushed off the line.

 

NICE !!!

 

Why not compare it to a LT1/LS1??

 

Actually, I think that cam is a bit conservative. If it were me, I'd look for a grind with something no less than .510's lift. But, I like BIG cams.

When you compare cars, Torque to weight ratio will usually dictate the winner. The stock 305 was given so much smog equipment and conservative tuning that they were choked out. But they actually did pretty well in terms of GM's power output. My '79 Z28 was originally rated at 175 horsepower and that was with a 350!

Allowing that 305 to breathe better, you shouldn't have any problems at all getting it to output no less than 300 horsepower.

 

The reason I compaired the V6 and z28 is because there both mine and there made the same year.
As far as lift on that cam goes, if I put 1.6 rockers on it that should push the intake lift to about .485'' and the exhaust lift to about .511'' + or - a few thousands.
I'll realy feel it on the low end.