I would go with a F1C. It still fits on the stock ATI bracket.

 

if staying aluminum, go forged 347 or 402. you'll make plenty of power with either.

 

I would go with a built 346 for a D1SC. Maybe even a 383.

 

Everyone has a pretty broad range of opinions. From 346-402+. Anyone have experience with their opinions or specific reasoning.

 

I've done alot of research for a build I'm planning out... and everyone's telling me to make MAX power with a vortech Xi, I'm best off with a motor under 380 ci. The cyl's will be able to be filled better, and it will make more power.

Goal, is 1400 hp at the crank fwiw.

 

This is the info. Im looking for. On a side note how in size does that blower compare to the d1sc?

I'm still learning on what is the right motor setup with what power adder.

For example i'm wondering if you can have to much bore and not enough stroke?, or visa-versa to much stroke and not enough bore? Just curious what it takes to get the most potential out of your power adder. Or am I wrong about it? Like said above, you were told under 380 ci. Why exactly? What about below a 380 is better than a 402? Is it more or less a best bang for the buck scenerio or will the smaller motor actually make more power? I've always been under the impression more cubes will make more power.

Thanks for all the help guys. Keep the info. coming. I could probably just call a few of our sponsors, but i'm sure im not the only one with these questions.

 

The vortech Xi is close to an F1c/F1R, somewhere in the middle of the 2. We're looking at putting something together that's in the 3.5 stroke/4.155 bore together. The larger bore will allow you to run a head with the bigger vlaves which will help fill the cyl's alot better, and the larger exhaust valves will help get everything out too. Cubic inches are cubic inehes for the most part from what I'm being told. Smaller CI will allow the blower to fill the cyl's alot better and you won't have to worry about running out of airflow (boost) once you start getting into the higher RPM's

I'm debating on the drysump for my application, if I do end up with a dry sump, or even an external wet sump pump I will be able to spin this to 9000 rpm, which when you have a limited blower size, will result in a faster car. More times the cyl's fine going down the track the more power it's making, if that makes sense.

For a street setup that's probably on a stock oil system you want to limit the rpm to about 7500 I'd think, so pulley for max impeller speed at 7500 and set your rev limiter there would be my advise (if you're running a belt which I assume), and then figure out how much air that will be moving (the blower), figure that at the max amount that it can see. Then figure out how many CI that can feed, and build something in that size or a touch smaller and you should be in good shape.

 

Anyone ever do a 365ci? Wondering if I could find a burnt up ls2 and just forge it. Im not really wanting to buy a crank if its not gonna make that much of a difference, but I think i'm pretty set on staying alluminum. Alot of these procharger setups have enough heat problems without a iron block retaining so much heat under the hood. Also I've added enough weight as it is. I called VA speed and was quoted 4800 plus shipping for a 402 shortblock.

 

You could do that, KP had a stock stroke ls2 I think in the black car ebfore be sold it and that worked out pretty good.

Just keep it on the small side (motor CI) and you'll be o.k., you don't want it running out of air, which the bigger the motor the more this becomes an issue. Granted, if you're gonna keep the motor redline 7000 rpm you can probably put a D1sc on a 408 and not run out of you spin it to max impeller speed, but the slightly smaller motor, shorter stroke and slightly smaller bore (4.0 vs 4.030) will be a little happier at slightly more RPM, and I bet it will make just as much power. Piston design will be better too since you're not pulling them down so far with the shorter stroke.

That's my opinion after talking to a couple people, seems to be the genaral consensus of people racing with a limited blower size.

Also look into the cog or 12 rib or whatever the best drive system you can right off the bat, in the long run you will be glad you did.

 

I have a full sdce setup. Hopefully that will do the trick. If not ill look into a cog setup. Have you decided what heads/intake your gonna run?

Also there are some weisco 4.005 pistons for sale in the sale section. -8cc relief. Any idea on what the compression would be with a 65cc head? I'm looking at the TFS 225s. I'm on E85 and meth so I could probably stand a little more compression to help aid in some power, but i'm not sure what the ideal number is.

 

No idea, IMO, when it comes to something like this I'd make sure all the parts are gonna do what you want them to do.

There's a program you can get a free download of, it's called engine calculator, search that on yahoo and it should come up, helpful for determining compression ratio, etc.

I'm far enough away from building the motor so I can wait until a couple of the new parts that are coming will be available in time for me to use them, I'm considering the GM LSX DR heads... for an inline valve head, they look to be one of the best options out there for what I want to do along with the intake that they are making to go with them (single plane) If those aren't available when I'm ready to get started, it will either be an Allpro LSW, or one of Cary's heads, which one, I am unsure at this point. I'd like to say I can spend the $ on canted valve heads, but it's not in the budget, and I don't think they're needed to get where I want to be.

Right now, if the lsx DR head was available, I would be using those with a std deckheight RHS block, the raised cam in that block will help with valvetrain stability for the 8500 rpm I want to be able to turn the motor, the priority oiling, block strength are all there too. I'm looking at putting a 4.155 bore, 3.5 stroke together as well, that way the bore is big enough to utilize the large valves that the heads some with, stroke is nice and short, so the harmonics should be reduced helping keep the gear drive bushings happy, and it puts the CI where I want it. Planning on a center counterweighted crank, and alum. rods, to keep things as light as possible and get the balance as good as we can. Also going to have the crank made with a BBC snout as well, so that the crank is strongest where it needs to be.


This is for an extreme application, I'm not jumping in lightly, we're aiming for 1200 to 1400 hp at the crank, for a street application this type of stuff is way overkill that I'm sure of... but I always overbuild for the goal in hopes of increasing reliability.

 

Bringing this back up.

I have a couple options right now. I have a iron 6.0 block that I had planned on doing something with (365,370,etc.), but apparently a spun cam bearing is a bigger deal than I had planned(Do they make oversized cam bearings and would it be problematic). Anyone know my options with this?

Next the stock ls1 is still in my car and is doing great. I would really like more power though and i'm pushing it past its limits right now. So if the iron block isn't worth messing with should I do a forged 347 or 383 and why. I've heard the only downfall to the 383 is head choice, but afr has a small bore head that would take care of the job I believe.

Either combination will have my d1sc spinning to the max. My car is on E85 so a little more compression with whichever combo might be a possibility.

 

Go with a 370. 4.030 bore gives you a better choice of heads. Mines done and I'm trying to get it in the car soon.

 

Well I ended up getting a LS2 block a couple weekends ago. Currently shopping for a 402/404 rotating assembly. Been looking at livernois alot.

Also my D1 will be up for sale shortly. Gonna be in the market for a F1C/R

Also the Iron block was fixable with some Gen IV cam bearings.

 

Let me know what you find an F-series head unit for.

 

I'm interested in the D1 head unit. Let me now ASAP.

 

I have pmd the price to people who have asked about my head unit. If anyone else is interested pm me.