Specifics on car.. stock 305 bottom end. Ported LT1 heads, LT1 intake, 24# injectors, 1 5/8 headers, K&N CAI, 3" hi-flow cat, 3" SLP cat-back. Compression ratio will probably be around 9.8:1.

Possible cams that I have access to...

Speed Pro cam of some sort
222*/232* int/exh duration @.050"
.479"/.501" int/exh lift with 1.5s (.511"/.534" with 1.6s)
LSA of 114

Crane Cams Compucam 2031
208*/218* int/exh duration @.050"
.438"/.458" int/exh lift with 1.5s (.467"/.488" with 1.6s)
LSA of 112


I haven't decided on valvetrain just yet. Will probably be stock 1.5 rockers until I throw on some 1.6RRs (since they are easy to replace after the fact). Also haven't decided yet whether I will go with larger valves than the 1.94/1.5 (if anything it'd be 2.00/1.55) or stick stock for now. Heads should flow about 260/190 at .550" lift and 240/175 at .450" lift with the stock valves.

The Crane Cams cam will give me better low-end and sacrifice very little top-end, but I can't help but think that it feels like its wasting my ported heads since most of the flow gains will come in the bigger lifts. If the Crane Cam had a bit more lift, it'd be obvious which to go with. Will that little lift be a big deal?

The advantages of the Crane Cam would be that it should be much easier to tune and that it would allow me to use the stock LT1 springs. Advantages of the Speed Pro are more lift and more duration (though not necessarily a good thing for my 305).

Any estimates on times with a 3000-3200 stall torque converter, 3.xx gears, and a 3400lb (including me) car? My goal was to hit low 13's with this motor without nitrous/boost and not diving into the internals

 

The first one you listed IMO...

 

Desktop dyno shows them both having similar HP outputs, with obviously the bigger cam giving it a few hundred RPM later, but the low-end torque is of course more with the smaller cam. However, I'm not a big fan of comparing different cams in DD2k because it doesn't seem to take into account lift much.

I know the smaller one will be easier to tune, but looking at some flowcharts of heads that should flow similarly to mine, most of the benefits of the port job are with higher lifts. Then again, this smaller cam is kinda weak to put into a 350 anyways, so I guess I may as well use it in the 305 and then get a better cam to take more advantage of the heads whenever I go to a 350.

I have the SpeedPro cam laying here in my room right now and will be trading it to a buddy living around here for the Crane Cams. He needs a bigger cam for his 350/383, and I think I might want a bit smaller cam for my 305

This Crane Cam looked good until I compared it to the XE256 specs, and it looks smaller than the XE256. Though I guess its probably pretty easy to overcam a 305..

 

Actually I think the first one will tune easier due to it's 114 LSA vs. the other cams 112. My cam has a 114.5 LSA with a 530 lift for my 305...

 

The decision is ultimately going to depends on your priorities. Do you want this to be a fun, low rpm street cruiser type... or are you willing to sacrifice that torque in favor of more top end horsepower. One suggestion I may make: Take a serious look at the GM LT1 HOT cam package. With a factory designed cam specifically for the LT1 intake and heads, matching valve springs/locks/retainers, AND 1.6 RR all for about $500... you really can't go wrong. Obviously it was designed for a 350 engine, but still, that's one hell of a deal. Besides, with the smaller bore of the 305, the mixture will burn faster... which i assume will make tuning easier than it would be with a 350. You just won't be making as much torque obviously.

 

You mean the LT4 Hot Cam though? That was one of my first choices and I got this other one instead. I don't know about a cam being easier to tune on a 305 than on a 350...that's against most logic. But, I already have the SpeedPro cam and David is willing to trade me what he has so its between these two cams.

The LSA difference is 2 degrees. The valve durations are different by 14 degrees...I'm pretty sure that will overcome the 2* difference in LSA.

The other advantage to using the low-lift Crane Cam is that I could use the stock LT1 springs on this motor for now.

I think I'll just go with that one and upgrade the cam when I go to a 350 eventually. Or I'll just sell the car once I make it a low 13-second 305 in favor of the next project car, a mid 80's to early 90's 'Vette

 

Wow... where to start...

The 114 vs 112 arguement doesn't work for me. You are still tuning the same stuff: idle, p/t, wot etc that you would with either. I have a 112 and it tuned just as easy as my buddy w/ a similar cam on a 114.

The 222/232 is almost too big for a 305... I would be 100x more tempted to run a LT4 hotcam in a 305. Similar in duration, but has good idle characteristics for the 305 setup.

The fact that DD2k shows them with similar power outputs shows how inaccurate it is. That is completely stupid. They shouldn't be close IMO...

The second will have more power, higher in the band etc, while the other will have more torque. The first will be more TPI friendly dude to the rev limitation of the intake...

It all depends on what you want with the car. The first will be more friendly IMO.

 

Its not going to have a TPI intake. Its going to be an LT1 intake, much more free-flowing. LT4 Hot Cam is like 219/228 I think, right?

 

218/228 IIRC.... LS1hotcam is a 219/228

W/ that intake that cam will work well...

 

Well, since you have a short runner intake and good set of heads might as well go with the larger camshaft. Unfortunately you really have setup going for a 350ci or larger engine. With the 305 you better put at least a 3800-4000 stall and 4.10+ gear though if you want the car to perform at all. Otherwise I can promise you it won't be much of a 1/4 mile performer. IMO, you should have stayed with the stock TPI(ported of course), use a smaller cylinder head with 1.94/1.50 valves and run a smaller camshaft(212/218 Extreme). Use around a 2800 converter with 3.73's. All this will make a very strong combination for a street/strip car. As 1320's post mentioned earlier you have to figure out a plan for the car. Is it street only, street/strip, or strip only? If it's strip only, then the above combo may actually work ok as long as your running plenty of stall and gear. Without it, this combo will be a dog. Good luck.

 

Looking at 3000-3200 stall 9.5" torque converter, and 3.42-3.73 gears.

It is a street car (daily driver, in fact), but I hit the track. I want a solid 13-sec car. Most likely, this will all eventually be transplanted to a 350, but I want to see what I can make the 305 do, and since all of the parts (except maybe the cam) can swap over to a 350, I don't feel that I'm wasting any money at all.

This cam is only 4* more duration-wise than the LT4 Hot Cam, and has a bit more LSA to make up for that slightly (in tuneability). Also has more lift. Only downside is I'll need new springs, but I should buy new springs anyways (probably EX-612s).

I want it freely revving to 6000, and that should be no problem with this setup. I think I'll just go with the bigger cam because it will take better advantage of the heads.

 

well, good to see that you've made a decision. Let us know how it all turns out, cuz i'm anxious to see what your 305 can do. I'm not much of a 305 fan, but did you see the 340 HP 305 engine Lunati built?

 

Hmm I remember that. I think they started off with an LG4 (but changed everything anyways).

If that 340HP was at the crank, I'm hoping to best that Should be possible..

 

To properly calculate in desktop dyno, you'll need head flow numbers, as well as other specifics on the motor.

Seconly, its better to enter the cam seat-to-seat, rather than at .050.

You think the compression will be 9.8:1 ?

-- Joe

 

Interesting. I'll have to look into the seat-to-seat and the @.050" differences. I was using some flow ratings I got off of camaroz28.com that someone did of their home-ported heads.

I'm guessing at 9.8:1 using thin gaskets. With .041" gaskets, I'm guessing I'd be back around where I'm at now. The LT1 heads have 54cc chambers whereas the 081 heads have 58cc chambers.

 

Technically for desktop dyno you need both seat-to-seat AND .050" lift because it needs both to calculate ramp rate which plays a part in the power output...

 

Ewww disgusting. Thanks for telling me about the seat-to-seat thing working better. 297/307 advertised. This will KILL my torque. With the @.050" settings, it looked like I'd have roughly 275ft-lb torque at 2000RPM. With the seat-to-seat settings (and other settings changed accordingly), I barely have 200ft-lb at 2000RPM and peak torque is just under 350.

Now, I realize these numbers aren't very accurate to real-world. I'm mainly using DD to compare different cams and to see how power curves shift to compare. I'm not looking at the actual numbers a whole lot.

I think I'll be going with the smaller cam.

 

With a 3000 stall, what do you care about torque at 2000 for?

 

lol true...I was just using that as an example. Nevertheless, looking at the cam with the seat-to-seat specs vs. the @.050 specs, it lost nearly 50lb-ft everywhere, and peak HP was at like 7800RPM, lol. I think I'd probably be better off with the smaller cam..

 

Stock LT1 heads are 58cc while the LT4 heads are 54cc. That is how the LT4 motor has 10.8:1 while the LT1 has 10.5:1.