With temporary money problems clearing up I'm back to my 1996 build (ie: money pit ). Below is my specs and info from Lloyd Elliott.

Couple of questions...

1) I've decided to refresh the block and was (possibly) thinking 355cid while it's at the machine shop. Can I do it with the info/parts below or will I have to change things (I won't do it then and will stick with stock block & internals)?

2) I think Lloyd mis heard me and thinks I have a 3200 TQ. I have not purchased it yet, with the build specs should I get the 3200 (or 2800/3000). I've not yet wrapped my head around the TQ and fear the higher number will affect driveability

My specs

1996 A4(stock rebuild) with 3.07 rear

LE2 build (with Manley 2.00/1.56 valves and Lunati dbl springs)

222/228 .570/.565 110 LSA camshaft and all supporting parts and the “while you’re in there” parts (water pump, rebuilt Opti, timing chain, etc...)

Ported intake

30lbs FIC injectors

48mm TB

I’ve purchased all parts except Torque Converter, Headers, push rods and tuning (mail order 1st( (Moe Bailey), maybe dyno tune 2nd

Exhaust will be LT headers to X-pipe(no resonator) to stock mufflers

From Lloyd Elliott

If you are still needing to pass emissions, we can do a 222/228 .570/.565 110 LSA camshaft that will have an idle similar to a Hot Cam but make more HP/TQ everywhere. Mild enough to work with the 3.07 gears that you are planning on running and a mild stall. RPM range would be about 1700-6200 RPM. In OD with the converter locked up, this cam can be lugged down to 1600-1700 RPM without bucking and surging (with good tuning).

Your Yank/Vigilante 3200 will work AWESOME with this camshaft.

I also have braking (EBC) stuff and some suspension items as well, but that is for another thread

TIA

 

If you are on the fence to bore it or not, why leave 5cu in. on the table. If it is already disassembled, why not?

I don't think a 3200 stall converter would be too much. This will depend on how much traffic you plan on driving it in if you will even notice much. With the converter and Cam, tyhe car would love a 3.54/3.73 rear gear.

 

I plan on using it as a cruiser, light to light, 20 - 80+ mph.....no auto-crossing or drag racing(maybe, but not hard core and once in awhile)

The block is out, but not disassembled. I was going to clean up and paint, but hot tank(less simple green usage), new freeze out plugs, general inspection and recommendation. The pistons are (I believe) hypereutectic (not forged, but not cast....I plan on keeping it NA) and I'd rather not go through the expense of new piston, connect rods, crank. BUT if I can use my above inventory of parts (and cam specs) and the machinist is concerned about my stock internals(90K miles), I might consider a 355cid (more torque, right?).

I want to keep the rear at 3.07, as I bought this car for my wife as a cruiser(hell, I bought stock ac delco shocks....been there done that with the Bilsrteins...but now? too late)....but I went and blew the head gasket, so now I created Frankenstein's monster (subconsciously, I always wanted to build a motor ).

IF, I went to a 3.45/3.54, how would that affect things? It's "cammed" for a 3.07 rear. Would I stay with a 3200 TC?

I plan on proceeding, but I wanted to get opinions on the change to 355cid and bumping up the gears. This thing is costing a small fortune, but what a bit more (and is it worth it?)

 

This makes me really think you would like a 3.73

This is a lot or work to regret not going into the bottom end later. To be completely honest, I have seen a few of the LT based cars survive into the 200Ks, but the LTs are not exactly known for their longevity. (Many reasons for this) Only you can answer how much you know about the history of the car, how it has been cared for and driven. I would recommend a tear down, inspection, machining as necessary, and re-use old parts that check good. I would recommend new bearings, rings, and gaskets as needed. Just for the piece of mind. Instead of a rebuild, think of this as an overhaul. I think getting your heads freshened up and new seals and guides would also be good money spent. You could get through this without buying a new crank, rods, pistons, or cam and have peace of mind. Although, now is a great time for a that new Cam!

Hypereutectic is not a type of piston - it is a type of cast piston, it is the result of manufacturing method. It is a cast piston that has a higher % of silicon than normal aluminum casting alloys, it is heated and cooled precisely to to reach equal distribution and solution of the silicon in the aluminum alloy. I set up a line for doing all the work to this type of piston after casting, and machining was a pain compared to other aluminum. Don't even get me started on tolerances.


Phase Diagram


Yup, I won't pull mine out to just rebuild it either. If it let's go for some reason, I am going 383. Did a 355 in a Thirdgen F-Body once... should have done a 383.

I have never heard of "Cammed" for a gear, but rather geared for a Cam. In a very simplistic view gearing multiplies torque... or provides mechanical advantage. Like a lever arm. Hp is the ability to produce torque at speed... or rather power is the ability to produce force over distance (Work) relative to time. What is produced at the wheel and moves the car is Force. The force produced at the wheels changes between gears because when a gear change occurs, the mechanical advantage changes. The same power and torque is available through the RPM range regardless of gear, but what forces reaches the tire is dependent on gearing. Since HP is calculated by Torque*RPM/5252 the HP curve changes very little. As Force goes down, speed goes up proportionally in relation to gear ratio.



With all that being said, people like to talk Horsepower because it tells you want the engine is capable of. How much speed (RPMs) you have to be able to take use mechanical advantage. Gearing needs to be deep enough to produce force to accelerate (F=M*a or in this case a=F/M). Yup it gets more complicated than this as you add wind resistance at speed and the wind resistance increases exponentially with velocity and becomes a bigger factor than mass quickly. However, you can't go so low (numerically high number) that when you shift gears you are in the middle of your power band or you will not use "All the area under the curve" of your HP curve. As in, having 18 speeds doesn't help if all you are doing is shifting and not accelerating. That helps a lot moving heavy loads, but shifting takes time (Like an 18 wheeler). If you go too high, you don't accelerate well, but can get really high top speeds (Like Land Speed racers getting a push start).

Looking at the cam specs you posted. This is a performance cam, looking at the 2500-5500 RPM Range. This is not out of the operating range for the LT1 intake or heads. So, you should make good smooth power across the range. The factory LT1 cam should shine in the 1500-4500 RPM Range. I know they make power above that, but if you look at the torque curve, around 4500 is where it starts to fall off, but RPM keeps climbing at a higher rate so you are still able to make more power because the torque doesn't just take a nose dive. It does start to decrease more rapidly after 5000 RPMS though.

So, expect the same with your Cam, but to a lesser degree because you are not changing heads with it. You should make usable power to around 6000-6250 Though you have shifted your "power band" up in the RPM Range. Gearing will help get you there quicker, and you have more RPM to utilize. All said, that Cam is not for a 3.07 gear unless you are going for some top speed runs. That Cam is begging for a 3.73. However, a 3.54 is an easier swap because you can just get the entire center section and swap them easier that swapping a gear.

The converter will also like the Cam/Gear Combo. The effect should be quicker acceleration, more "punch" when you floor it and down shift, and a bigger smile.

If you haven't gathered, I would change the gear. I would be more concerned with that than the 5cu-in. If you build a healthy 350 small block making 425hp. That is 1.21hp/cu.in. Absolute best case scenario, with a 355 that same build makes 431hp. Those extra 5 cubes that come from a slight bore will not drastically change any of the dynamics about the motor. It's not like the decision of building a 383 and deciding if you are going short stoke 400 or long stroke 350 to get there.

These are my opinions with my reasoning behind them. You car will love a 3.54/3.73 gear with the set up you are going for, but it will also do fine with a 3.07. I wouldn't sweat the 355 vs. 350 option. It is just a .030" over bore and is just a typical rebuild cut to clean cylinder bores. It's not enough to even get heat and water jacket issues i used to hear about. This isn't a "performance" change to the block. Having it machined to clear a 400 crank and building a 383 is a "performance" decision. I would honestly leave the .030" over bore up to the builder inspecting your block. The cylinder walls either need it or they don't.

Good Luck, and most importantly have fun!

 

I think I left out one portion of information you will want.

I used a 275/40R17 Tire for these calculations, 4L60E Transmission, assuming your build will make peak HP around 6200RPMs

Additional Torque Multiplication 3.07 to 3.54 is 15% by the rear gear

Total Torque Multiplication Per Gear

_____3.07___ 3.54
1st__ 9.39 __10.83
2nd__ 4.97 __5.73
3rd __3.07 __3.54
4th __2.14__ 2.48
(Sorry for crappy formatting)


What this means is at any given speed, you have more force to accelerate, but you are probably concerned about highway speeds as well.

3.54 at 70mph is about 2300 RPM (In my 6-speed I think this is about 1900 LOL)
3.07 at 70mph is about 1980. RPM.


Here is an idea of a WOT run with a 3.07 Gear:

And Now with the 3.54 Gear:


For S&G's, here is a 4.10, that would require about 2600 RPMs to run at 70mph



If you were tracking it more, we would talk about the number of shifts, anticipated trap speed, traction and a whole host of other things. If you were a weekend warrior I would be all over that 4.10 until you had a trap speed over 115mph (Roughly 425hp to the wheels). I have a supercharged LT4 and don't put that much power down.... yet!

 

Thanks for all that info Kyle! I should have explained my build a bit better. I am not a mechanic, but I've always liked cars/muscle cars. I have a friend who has a shop (2 lifts) that is about a 1/2 mile from my home.

Under his supervision I taken the engine and transmission out. The heads and intake were sent to Lloyd Elliott (www.elliottsportworks.com), he is very respected in the LT1 community and I had him do the LE2 package. When I misused the word "cammed", I meant that he based the grind of the cam on the 3.07 gears and driveability. I went through my emails with Lloyd before I posted this thread and I think there was some confusion on the Torque Conv., I believe he thinks I have a 3200 TC (I don't) and I'm wondering if this was additional info he used when he put together the package/cam.

The two main question I had when I started this thread was:

1) since the block is going to the machine shop and getting "overhauled", would going to a 355 have any benefit, especially if they recommend I "go further"...and can I with my original LE2 build (stock block, 350cid)?

2)If I were to go to 3.45/3.54 gear from a 3.07, would I still get a 3200 TC and is the cam (222/228 .570/.565 110 LSA) OK with the new/higher gearing?
I currently have 2.59 in the car and I bought a rear w/ 3.07(which I was going to have check out, seals, etc)

Thanks!

 

Since the block is going to the machine shop I would have them pull it apart and check the bore. If it is ok for just a hone I would do that. Then no need to rebalance with the new pistons. I would also have the rods rebuilt with ARP bolts. Then they should hopefully just have to polish the crank. Then the whole motor is fresh and ready to go.

 

5 extra cid is a 1.4% increase in displacement. If you make 400hp, it basically gets you an extra 5-6hp. If you are are going to need to overbore the block and get new pistons anyway, then go for it. I wouldn't spend the money on that just to get 5cid increase, though.


The cam LE has specified would be fine with 3.45 gears if you want to go that route, and it would also work well with the 3.07s. The 3200rpm t/c would be a big help with the 3.07s, and less critical but still useful with 3.45s. That cam isn't far off what I run (I have a bit less duration, similar lift, but 108 LSA), but in a 396 the extra displacement it effectively "tames" the cam a bit. My car has a very midrange-oriented power band, and I bet yours will to although it might have a slightly higher-rpm peak. If I were in your shoes and already a diff set up with 3.07 gears, I think I'd run the 3.07 gears and buy the 3200rpm t/c. Drive it a while and see how you like it, especially if highway cruising will still be important. I think you'll be pleasantly surprised, but you can always go with steeper gears later.

On the 96, you probably realize it's an OBD2 PCM (the only C4 with OBD2). As such, it may be subject to more stringent emissions inspection requirements. What tests do you have to pass in your locale? If you have to pass a tailpipe sniffer test, then the cam will matter (as LE mentioned). If you just have to pass a plug-in scanner test of you OBD2 diagnostics, you can do just about anything you want because you will be able to shut off any diagnostic tests it won't pass. For instance, my 96 doesn't have AIR installed anymore, and although it has cats it doesn't have the downstream O2 sensors installed. So the diagnostics for the rear O2 sensors are turned off so it will not report those, and it passes inspection. Ironically, the car will pass a tailpipe sniffer test, but they don't do those in my area. Anyway, you need to plan for this with a tuner or by tuning it yourself. The only tuning suite still available for our cars is Jet DST. No newer suites (e.g. HP Tuners) will work. So make sure you have this planned. The good news is that our PCMs are very "tunable" - you have lots of latitude to make it run well with almost any engine build you can dream up.

 

You can, let your builder tell you if it needs it. "If you build a healthy 350 small block making 425hp. That is 1.21hp/cu.in. Absolute best case scenario, with a 355 that same build makes 431hp". Not enough to worry about it.

Yes, your Cam wants to rev higher, your converter wants to be hooked up to an engine that revs higher, and those LE2 heads want more RPM. You should go lower (numerically higher) than 3.07. See Below, this is an LT1 Dyno Grpah I found with a 226/230 Cam, they had additional modifications such as long tubes and ported intake. You can see as I said, between 2500-5500 the car has a nice torque curve to work with and it doesn't nose dive after and makes power to 6200 RPM. It's a nice set up, but it is going to want to rev.


LE2 Dyno

 

Matts on the money, it all has to play together. Lumpy cams, tall gears and slipping converters suck.
If you want more torque put a bigger crank in it or more gear in your 350...not sure Id lean on a stock 90k bottom end. You can but youll always have that little voice in the back of your head

 

Thank guys this info is great!

I like Matt's suggestion, run the 3.07, if I want taller gears access and changing them should not be to difficult. As I mentioned, I'd like to get a dyno tune (after initial mail order tune) and I could do that if I jump up to 3.54. The D36 w/ 3.07 I'll have checked out before install and if it going to take some money to "refresh it" than I might go to the 3.54s. What kind of money am I looking at (gears & labor)?

With the 3.54s, should I stick with the 3200TC or go down to 3000?

Thanks again!

 

Zip Corvette is asking $450.00 for a set of 3.54's. With that, and the labor to get them set up, especially if you don't do the pull out yourself, well you are already over 1/2 what you can get a Dana 44 for and have the better rear-end and gears.

There are probably other places to get them less expensive, just Zip was the first one that showed up in a Google search.

 

I bought the 3.07 from a CF member and its out of the car. So approx $450 for the gears, how much is labor to do the switch?

Probably better off having them do the rear with the 2.59s and sell the 3.07 to recoup some of the 3.54s cost

 

Read the below. My son spent a couple hundred to just have gears shimmed in

http://garage.grumpysperformance.com...to-3-54.10659/

 

I have the LE2 build but my cam is 227/234, .575/.570 110 LSA. It has a pretty lopey rough idle. I have a 3000 stall and it worked fine with 3.07. However, I have since gone to a 4.11 Dana 44. My personal opinion the tall overdirive gear with 3.07 diff left too much on the table and I was just lugging around town.