My question is what 5 spd. transmission would work with it. If need be, yes, I'd use a 4 spd from a 930, but could that transmission handle 400 hp? Or 500 hp?

The 4 speed is fine as-is. The G50 variants work, but may need modifications to live long. Billet side bearing plates. Spray bars or at least an external oil pump and oil cooler. Hardened shafts and gears. Race conditions are unforgiving, but you can be gentle on the street and make a stock G50 work.

New or used engine? How much to rebuild? Any flaws in the engine that I should know about?

The all-aluminum LS1/LS6/LS2/LS7 weighs about 350-400 lbs dressed with fuel injection and accessories.

Stock 505hp LS7 has titanium rods and dry-sump lube and is available as a crate motor for under $14000. The 400hp LS2 runs around $5000. Or spend a bit more to have a specialist build one for you based on your needs. A common mid-six-liter stroker runs under $10,000 and easily makes 500-600 horsepower depending on state of tune.

Refreshening runs about $1000 for new rings, bearings, gaskets, and fasteners.

Flaws are few, especially in the naturally aspirated 400-500hp range. I'd be much more worried about transmission issues.

http://www.pelicanbbs.com/showthread.php?s=&threadid=286734&perpage=20&pagen umber=6

There was a great thread about someone's small-block powered 930. He had spec'd a high-revving destroked iron-block first-gen 302 (5.0L). I discussed designing a 7000rpm 340 cu in (103.25mm bore x 83mm stroke=5.6L) all-aluminum LSx based on the L92 Escalade block. The reduced torque of the destroked design should help the trans live longer. And they sound soooo sweet.

Kaisen - I've also been looking at a 944 or 968 for such a swap. Seems like Renegade likes the 944-style cars as much, if not more, than the 911s. They appear to be a bit more sturdy than the 911s for Chevy power.

Your thoughts?

930 4 speed is very stout, will easily handle 400-500 hp.

With big displacement and torque, 4 forward gears are sufficient.

For a 5 speed, 400-500 hp through a 915 would be a bit more controversial. I've witnessed around 350-360 hp run through a 915 for many years and tens of thousands of street miles with no problem at all in a couple of different cars. These are not used as race cars or dragsters, though. They are not babied, but there is a limit to how hard you can drive on the streets.

I think you can find some that would say a 915 can handle 400 or maybe even 450 hp. I'm more conservative, and if I were going to run much more than 350 hp and the corresponding torque of a SBC V8, I'd move to a 930 box.

This is a big swap with the RX-7 crowd. Many guys with 3rd Generation and 2nd Generation RX-7's swap in LS1's after blowing 3 or 4 engines in a row.

As a Rotary enthusiest I am happy they do this because it leaves more cores for me to use.

http://www.hinsonsupercars.com/
These guys are one of the leaders in the swaps. An RX-7 with a blown engine can be picked up for as little as $100.

I'm not disputing the numbers, but I've always wondered *how* a SBC engine (aluminum heads or not) can possibly be lighter than a 911 engine. Or maybe another way to word it is why are the Porsche engines so heavy in spite of their extensive use of lightweight alloys?

Me and a friend picked up a '72 911T engine (complete) and carried it into the back of a van. It wasn't that heavy. Surely not 400 lbs.

Mike

These same LS1 guys argue that their engine is lighter than a Rotary engine. It seems the LS1 is the lightest engine in the world. I gave up arguing with them. There is no winning that agrument.

All I know is I can pick up a Rotary short block by myself, 2 of us can walk around with a long block.

An employee of mine had an LS1 block shipped to our office, I took a picture of the bare block in the box, I need to find it, the bare block weighed over 150lbs as per the lable on the UPS freight box.

Besides, LS1's never loose they win at everything. ;)

I will add what I know, since I started this thread. Ive done a fair bit of reseach. A SBC WITH alum heads weighs about 50lb more than a 911 motor, and a bit less than a 930. A LS1 weighs about 100lb less than the SBC with alum heads. The 915 transaxle doesnt hold up well to the torque of a SBC, it should be modified, and you should not have a insainly powerful SBC mated to a 915. The 930 transaxle holds up well to a SBC. A LS1 is basically a SBC, but a aluminum block. The dry sump of the 911 is better, but you can add that to a SBC, but then the cost goes up. This conversion is a way to get a lot of HP into a pcar. Its not expensive, but its not cheap. $1600 conversion kit, $1100 radiator, $850 modified gas tank, $300 other misc items. The cost goes up from there if you upgrade parts ( hi torque starter, headers for SBC, better clutch\perssure plate ).

So for my salvage title 930 with NO engine. I can put a new 400HP engine in with high performance clutch parts to my 930 transaxle for $12000, and the engine will weight considerably less than the 930 engine. ( over 100lb )

Oh, and to add HP to a SBC or LS1 is very inexpensive compared to pcar mods. I would rather have a 930 engine, but since I have none, this option is my choice, plus my GM friends can actually work on this engine.

Do those weights include the added weight of a radiator, coolant, lines, etc?

I wonder what the net weight difference is on a converted car, in other words, a stock 911 or 930 v. the same car after it has been converted to SBC?

I just looked up the weight of an LS1 and here is what I found:

Total Dressed Engine Weight Auto. - 457.6 lbs. (208 kg);
Manual - 497.2 lbs (226 kg)

It's interesting that the manual weighs more than the automatic. Is that because of a beefier transmission, or if it's a six-speed, that six speeds weigh approx. 40 pounds more?

This is what I remember as one of the "equal-but-different" points about the V8 swap. I actually priced a V8 conversion for my car with Renegade, and IIRC, the least expensive I could do was $11,000. At that time, unrebuilt 3.6s were going down. Install would probably be a bit more for the V8 because of the radiator plumbing, but all-in-all, the cost was very close.

The issue, however, with the 3.6s was they were not new. The SBC I priced was a fresh crate motor.

The other things Renegade advised me were heavier torsion bars and a stouter transmission.

The engine I looked at put out, I believe, about 300 hp, which would make a mid-year car like mine fly.

As for weight, what I would consider is where the weight is. A flat 6 has its weight down low, while a V8, being taller, might be lighter, but has more weight up high.

I equate flat 6 vs. V8 weight to running backs, in how it's a lot easier to tackle or "tip" a tall back - like Marcus Allen or Eric Dickerson, than a smaller back with a low center of gravity - Jerome Bettis, Tiki Barber or Warrick Dunn.

I don't know: I just thought I'd throw in a football analogy. ;)

The radiator I bought is aluminum, it weighs nothing, your looking at basically the same weight as a up front oil cooler.

What I always thought would be "cool" is a turboed LS1 style (all aluminum) motor in a 914.

Good point! I have to now wonder how much it weighs when full?

That also makes me wonder if anyone has weighed an LS1 fully wet and how much weight it gains.

I never thought of that.

Here's a candidate

http://www.thesamba.com/vw/classifieds/detail.php?id=391697