Remember that the most important thing on a car is the cam. The cam will dictate the way the car will react to your foot and to its own way of giving out power (ie driving).

A good SC'd cam is not a good NA cam... probably will work better than a stock one, but will not yield its full potential...

You can work the heads and install a SC cam... for instance an XE cam 224/236 114lsa as I have. It will work well for a NA but not to its full capacity. But when you do put a SC this cam will shine in... As Rich might say.. you dont want to blow out your expensive boost out of the exhaust with the 112-110 lsa (more overlap).

But you can do it one step at a time...

Just use the supercharger cam first, so you dont have to do that whole work AGAIN...

 

Senior Highlander which AFR heads are you using?

 

This discussion has me asking myself "what if I had gone N/A". So I've got to know some things here. My stock SC'd LT1 makes 402 RWTQ at 4,400 RPM .....and about 410 lbs of torque at the flywheel at 2,200 RPM (350 RWTQ). Could a mild heads/cam motor put out comparable torque or would the comparison be limited to high RPM and midrage? It kind of makes me sick that an N/A motor (say a CC306 with really good heads, TB, tuning, etc) can actually make more top end than mine. But what about say .... 2K to 5K RPM? Would mine at least own an N/A motor in that range? (about 400 lbs torque at the flywheel at 2K RPM and 435 flywheel HP at 5K RPM). I would think an N/A motor would have less response at the lower end and obviously less vacuum and off idle response (not nearly the MPG either) ......so did I reap any benefits going with the blown/stock LT1 over a cam/heads version? I have to admit I wish I had the cam sound and the extended RPM range with some 4.10's and a 12-bolt .....would be more fun to drive maybe? Someday when this thing pops a piston maybe I'll do it all Need a better paying job first so I'm praying it will hold together for a couple of years or so

 

Engineer, I wouldn't recommend that your friend put together that combo. The car would run no where near what it should run. The cam you have chosen does not look like a NA cam and is much smaller than even the hotcam. I just think that would be WAY to small for a stroker motor.

 

I just can across a great deal on some parts to build a smoken 383. It looks like the SC option will have to wait for another motor. When I am finished later this spring I will post my dyno numbers and costs to see how they compare with what people spend on the SC kits. Thanks for all the input!

 

Kreinmc, the cam is fine. The duration of the 214/224 Extreme high lift lobes (31XX), when measured at .200" lift is very similar to the famous CC306, but the Extreme cam has more lift. The "small" Extreme cam has .565" lift versus only .544" for the 306. So, the two cams have very similar areas under the lift curve, but the Extreme has shorter duration, so it will give better low end and the same mid and top end as the 306.

Also, I'm running the Crane 210/224 cam. This cam is smaller and NOT and Extreme cam, so the area under the curve isn't that great. But, I managed 340 rwhp with a set of mildly ported stock heads and shorty headers through an automatic. If I had upgraded to a stroker, got better heads, a more aggressive small cam, and full-length headers, 400+ rwhp is entirely possible.

There's alot to be said for cam ramp rates.


CANBAUFO, if the cam is well matched to the compression ratio, a NA motor will make more low-end than a centrifugally supercharged motor. This is evidenced by the fact that most supercharged LT-1's make great rwhp, but don't run as well as their same-hp NA couterparts. 410 rwhp will put a NA full weight car over 120 mph in the quarter, but S/C would need 430 because of the lack of low-end and mid-range.

Mike

 

That's a little depressing .....just how serious of an N/A motor are we talking about here? Would it be nearly as streetable as a blown stocker or are we talking "shaking out your fillings at idle and sucking gas"? So for example, a 350ci N/A motor with a CC306/good heads with everything matched up and tuned right would make more than 350 RWTQ at 2,200 RPM and more than 402 RWTQ at 4,400 RPM......AND more than 400 peak RWHP Really!? How high is the redline with the CC306....like 6,600 or so?

 

I'd say that there are reliability, tuning, and headache advantages to the supercharged stocker.

You can install a supercharger in a day, whereas a stroker will take a month or more to complete start to finish.

The NA cam would need to be 220+ duration and wouldn't idle bad, but worse than stock.

Strokers require extensive machining, clearancing, and other headaches.

Tuning is much easier with a S/C since it comes with an FMU and retard box.

All said, if I had to do the work myself, I'd go supercharged, but if someone else did it, I'd go N/A.

Mike

 

Thanks, but I'm not inquiring about a stroker here. Just stock short block vs stock short block/ N/A heads/cam/350 vs 7 ~ 8 PSI/350. I seriously doubt a heads/cam 350 with the same max power as mine makes as much torque from 2 ~ 4K RPM. Besides, in a race you aren't dipping below 4K RPM so what does the low and midrange really matter except for coming out of the hole? (which our cars try to do too quickly anyway). I would think the biggest advantage of a heads/cam motor over one like mine would be the extended RPM range and corresponding ability to gear lower and stay in the gears longer. I knew a stroker would be the way to go but that didn't fit my budget and still doesn't. All in all since I had someone else do most of the work I think heads/cam would have cost just as much but actually been easier to tune and more reliable (had the work been done right). I only had 37K on mine when I did the charger so I couldn't justify breaking into the motor. Now I could see it being more practical though.....because the stock crank and rods would have been fine to use for quite sometime. Now my pistons are on borrowed time

I guess what I was hoping is that my setup is more streetable/better MPG/ .......AND ......more torquey in the low to mid range. That's the only thing that makes me feel better about doing it but now you're telling me a heads/cam 350 has more bottom end ?!? ....oh well.

 

Since a centrifugal supercharger builds boost with rpm, you'll find that at low rpm, very little boost (and power gain) is being developed.

A heads/cam NA 350 with increased compression ratio and a well matched cam will make more low-end than stock. So, with a centrifugal only making 2# boost at low-end, they are comparable.

For comparison, my previous car was a 3rd gen with a 383 NA full weight and ran 11.09 at 122.7 mph. My new car is a 4th gen with 355 SC and ran 11.60 at 121.5. They both made very close to the same amount of horsepower and have the same torque converter and have similar weights. But, the NA car had a better mph and a much better et due to the better torque curve of the NA motor.

Mike

 

Yeah, I know what you mean about centrifugal blowers not making much until they're up in the RPM range. However, even at 3,000 RPM mine is already making 2.5 PSI ......not bad for a low PSI blower. It's a little hard for me to believe that a mild cammed 350 with similar max HP could make that much torque at 3,000 RPM (365 RWTQ) but I guess it's possible from what you're saying. It's just a little difficult to understand how but I can accept it (I guess )

Seems pretty obvious from your experience that what you claim is true unless for some reason your 3rd gen was quite a bit lighter and more aero than your 4th gen.

 

Well, don't make any decisions yet. I just noticed you are in Aurora. The most power i have seen a stock bottom end lt1 put down is 376 403tq, i think those are the correct numbers. That is from my friends formula with gtp heads, hot cam, etc. You cannot go with the same parts used at sea level. It is a different ball game up here. Smaller cams always yield more hp, small combustion chambers help too while big ones hurt. Etc, Etc. If you really want 400hp, your gonna need a supercharger or one hell of a solid roller setup/heads. Just my .02. btw, you should check out www.coloradof-body.com

 

Ditto what 94-3.4 said. I put an 8PSI ATI on my SS and the difference between Aurora and Dallas were crazy. Figure 400rwhp at sea level will be about 330rwhp there. Also figure on it lasting longer at that power level.

Mav

 

well I think superchargers are better than NA, but it depends on what your final goals are and how much money your willing to spend. You will notice many car manufactures going with them these days for good reason. A big cam doesn't idle well, the powerband is raised higher up and of course emissions get worse and gas mileage suffers. Of course either if the two will suffer gas mileage, but I bet the large cam suffers more because you can stay off the boost wheras cam is always gobbling. For the performance of a supercharger you can have great mileage. I read an article of a 96 camaro that passed emissions and made 650 horses with his supercharger. It looks as though your power range is nice and low, which is great for street driving, thats why people are always warned not to go to big with cams cause street driving will suffer. For arguement sake I think heads/cam is cheaper in the long run but supercharger can make so much more power with easy streetability. a 650 horse heads/cam car will have to be very large with high stall and low gears, comparing the two I think supercharger wins with that power level for drivability. I wish they made positive displacement blowers for our cars, that would be the cats meow, having 8 # at 2000 rpm. One company tried but couldn't keep the headgaskets from blowing. check out Skarodoms website it has some dyno charts under "main" and "products" he got 320 rwtq at 2500 rpm and 412 rwhp, so if your making 350 at 2500, I guess your not doing to bad. http://www.advancedinduction.com/

 

No kidding. What a FABULOUS opportunity