Well, I have a chance at a virtually free LO3 that I could drop in my '84 'maro (Z28) until I get my 5.3 ready to install. But the kid installed a Comp Magnum 270 HR cam, and a Performer 3706 intake manifold.
I checked Comp's website, and their description for this cam, ( they always base these descriptions on a 350, not a swirl-port 305 ) says 1800-5000 RPM, 270/270, 215/215, 500/500, 110@106. "Mild street performance, slightly noticeable lope at idle, needs intake and headers, 3.40-4.10 gears"
I have a 700R-4 with a stock 1500-stall, and a 3.23:1.
I think if I try this, It won't perform very well below 15 MPH, and it won't like the torque converter locked when I'm trying to cruise at 55 MPH. Worse, it may not like OD at all at my local pace of 40 MPH.

 

Probably a fair assessment of the outcome.

As cheeeeeeeeeeep as cams are in general, I think I'd make the change before dropping it in. Granted that's a roller and therefore not as cheeeeeep as some others, but still, even a used truck cam or something is likely to be a better choice.

 

what heads are on it?

 

swirl-ports.

 

Yeah. Before installation is the best time for a cam swap. And, I probably could and should sell this cam for enough to get a milder cam.
But trying it might be enlightening, and even if it works out as we expect, that's still educational by giving us confirmation. And it costs us nothing but a couple of hours of my labor, to try this combo before the cam swap.
The guy can't tell me how much idle vacuum it pulled, he says he never checked it.

 

I'm getting it Wednesday.

 

I dont think it would be that bad. It wouldnt be ideal.... but 3.23's arent too far below 3.40s, and it's not that big of a cam (duration-wise) that it wouldnt have much torque. I've got a flat tappet bigger than that with 3.27's and a the awfully tall T56 first gear. The fact that it's a roller cam will make it behave better than it otherwise would too.

I think it'd be fine. I'd rather keep the roller cam than have you switch it to a flat tappet one, that's for sure. But you just want something to run you around town until you get your 5.3 swap ready... i wouldnt spend any money on the cam. Just throw it in and see how well works - worst case scenario you can put some 3.42's or 3.73's in it and that will set you up for the future with the 5.3 anyway. You're not gonna leave the 5.3 stock, are you? It's gonna get a big nasty cam too, right? Throw some 3.73's in it and have fun with it.

EDIT: I just realize, we're talking a 305, not a 350.... that changes things a little... those power band assumptions are usually based on a 350. I'd still probably throw it in and see how well it worked because I wouldnt want to spend any money on a roller cam swap, but I'm a little less optimistic now. You may want to see if you can find a cheap regular LT1 cam or something for the minimum of cost and hassle.

 

make sure your springs in your heads can handle the lift.

 

you better find out if that guy changed the springs to handle that cam first.

 

Thank you, I planned to, but we are considering probable driveability, not the supporting hardware.

 

Fail / WIN!
While I was there to do the trade, I was looking around until he got off the phone. And what I brought home should give me some more power.
I got a pair of 416 heads that can go on my '95 LO5 short block assembly. Great except for 2 pulled rocker studs. I got a Professional Products intake manifold. ( Now I'll be ashamed to open my hood.) And I got a nicked and dinged Comp 08-413-8 cam. It rolls straight on a plate of glass, so it may not have been dropped.
I did my research before logging in, too.
"Good midrange power, noticeable idle, needs headers, 3.55-4.10, 2000 stall, 1500-5500"
I'm keeping my 3.23:1 gears until I break them, or until I drive them with the 5.3 / T76 / 4L80E, whichever comes first.
I'm keeping the stock torque converter until I drive this new combo.
Headers: Hedman 1.625" long-tubes.
Porting: I'll do a bit to these heads.

 

I started my grinding on these 416 heads;