I've been researching this, and I guess I'm wrong, but can somebody explain why...

When I get my motor built at a later date, I plan on building it for boost (approx. 12-18 psi) and using a Procharger D-1SC. My question is why wouldn't a 355 be a better blower motor than a 383? I would think that since a centrifugal builds boost with rpm, it would make sense to have a higher rpm motor, i.e. smaller cubes. I understand that it will make less lowend torque, but wouldn't the increase in actual psi seen up high make up for that?
Does my theory hold any water, or should I let it sink and start thinking 383?
BTW, my plan is to have a car capable of being a daily driver that will run 10s on 12 psi and 9s on 18.

 

Your theory certainly holds truth. Like you said, it is good to have a high revving engine to take full advantage of a centrifugal blower. But then, the higher revs will put more stress on the valvetrain etc.. However, I think a blown 383 would be more driver-friendly, so to say, because you don't have to wait as long for boost to kick in due to the torque. So if this is going to be your daily driver, do a 383. If this is a weekend-toy, do a 355. Just my opinion. Good luck.

 

I don't think it holds water. When people refer to adding more boost, what the goal is to get more airflow into the cylinders. If you simply were going for increasing boost then you could run a much smaller cam, less cubic inches, crappy heads, etc...and you will get more boost, just not more airflow which is what is important for making power. So the 355 might have more boost, but the 383 will make more power because it will move more air.

 

ROTFLMAO! ahahahah! daily driver, 9s ahahahah.

sorry, you just say that like it will be practical and easy. Do yourself a favor and buy another vehicle to drive on a daily basis.

 

Didn't say it WOULD, said it would be CAPABLE, as in, if I wanted to drive it to the other side of houston and got stuck in a traffic jam, I would be able to. If I spend this much money on a motor, I don't plan on wasting it sitting in rush hour traffic. Regardless, it can be done, just depends on how well it's built. I have a friend with a 93 mustang gt with a bennett built racing motor that runs mid 10s all day on motor and he drives it to work 3 days out of the week.

 

A 355 is easier and more economical to build for sure, you don't have to worry about crank or con rod clearance issues. Because the 383 has 28 more cubes, it is going to make more torque throughout the rpm range.

Guys on this board have run 10's with a blown 355. I think my car is capable of this too, just haven't tested it yet. I am content with the 355. Great street motor IMO.

 

A 355 has no real advantage as far as RPM's are concerned when compared to a 383.

7000-7,500 shift points would be on the high side for a street driven setup, which both engines are perfectly capable of.


I chose to build a 357 because that's enough cubes to make as much power as I need, it has a better R/S ratio, and I would rather have less bottom end torque so the car is more tractable on the street.

 

There was a guy that i have not heard about in awhile that used to have or possibly still has an Lt1 z28. It was a 355 with a Vortech and Aftercooler. I think it was an S-trim. Anyways it had a 218/230 114 lsa cam and head work. It could drive anywhere , and ran 10.5 at either 136 or 137. That would be a be a 9 second car with traction. That was with I think between 12 - 18 psi. I don't know if it was a daily driver, but whether it was or not . It could easily be. That is a very "mild" combo. It made 630+ at the wheels. I think the car weighed over 3600lbs.



There are a "few" 9 and 10 second daily drivers in Houston.

 

First of all, how can you tell his tone as to whether or not he is saying it "Like it will be practical or easy". We are on the computer. He may now what is involved... or he may not .


But again to make a comment like that. We are on the computer . You don't know how he was saying it, and whether he was just talking, or knows the cost and what is involved.

 

By the way, this is Houston.



I don't know about where you live , but around "these parts" LOL, 9 and 10 second true daily drivers are NOT an endagered species.


I am NOT saying that they are on every corner , but they are here. As well as quite a few other places across the country.


I live about 4 minutes from someone I have known for years, that has a 9 second daily driven z28.

 

He's right. They must put something in the gas around here because they're here. I know the cost and work involved because i've been researching this for a about 2 years now and haven't changed my mind on what i want. That's how I know what i want. And with the car getting up in miles now, it's about time to start thinking seriously again. Do it once, do it right.

I've also heard talk about 383s having some cooling problems, which would not mix well with the previously stated houston traffic OR high boost.

 

With boost- anything is possible. I intend to run 9's in a car that is fully capable of being streetable. In my definition- if it doesnt stall, and it doesnt overheat, it's a street car.

My combo will constist of a 355, adequate heads, and my P1.

 

I disagree that a 355 matches a centrifugal supercharger better than a 383.

Quite the opposite, actually. In many combinations, a certain amount of "mis-matching" works best:

-The Ford 302 is a short stroke engine (good for top end) with a long runner intake (good for midrange). Good combination.

-Any 383 LT-1 has a very short runner intake (good for top end) and a long stroke (good for bottom end). I've seen several 383 LT-1's run high 10's with a relatively mild hydraulic roller cam and pump gas. Good combination.

-305 TPI. Long runner intake matched to a long stroke crank. Bad combination.

I've seen this time and time again where one engine part makes up for the weakness of another. In a centrifugally supercharged engine, a stroker crank will add the bottom end torque the supercharger doesn't supply, making a good combination.

Another point that I'd like to make is that you have to buy a new forged rotating assembly anyway, right? In just about every case, forged 383 and 350 cranks are the same price, so why not upgrade?

Also, a 383 doesn't reduce top end over a 350. It does, however, dramatically increase midrange and moderately increase top end. I've seen naturally aspirated combinations pick up 35 ftlb torque and 6 hp by only increasing stroke .25".

Check out these sites:

http://members.***.net/blownz/

http://www.96silverz.cz28.com/dyno.htm

http://www.blackknightcamaro.com/

http://para.noid.org/~lj/

All are strokers and all are very fast cars. Most run 9's streetably.

A stroker motor can also reduce the need for a super high stall converter, again making it more streetable.

Mike

 

There is absolutely nothing wrong with a blower car using a 3.48" (stock) stroke. The thing is, it will be every bit as expensive as a stroker (unless it's a mild buildup using a stock crank) and won't make as much power. The fallacy in your reasoning is that you pulley the blower to make the desired boost at the desired rpm. IOW, provided the blower will flow enough air, the 383 can be set up to have the same boost/rpm curve as the short stroke motor.

Rich Krause

 

'daily driver' concern -> any noticable gas mileage differences in the 355 vs 383? (both properly tuned) ..on either a NA or boosted motor