waterbug1999

iTrader: (3)

Thanks for clearing that up... Ive heard that phrase before but didnt know what it mean... Thanks!!

Blue Hawk

There is two way of increasing the displacement in cubic inches of an engine: you can stroke it (increase the distance that the piston travel) or you can bore it (increase the diameter of the cylinders and put larger pistons).

With an LS1, the stock bore is 3.898 and the stock stroke is 3.622, that's equal 345.79 c.i. (or 346). The formula to calculate the displacement of an engine is:

bore x bore x stroke x number of cylinders x 0.7854

3.898 x 3.898 x 3.622 x 8 x 0.7854 = 345.79

By replacing your stock crankshaft with an aftermarket one that is slightly larger, you increase the distance that the piston travel into the cylinder (the stroke).

A 382 is an engine with stock bore and 4 inches of stroke.
A 383 is an engine with .005 inch overbore and 4 inches of stroke.
A 395 is an engine with .005 inch overbore and 4.125 inches of stroke.

Now, that's about the safest you can overstroke an LS1. Go over 4.125 inches and you can have problems with oil consumption.

You can also increase the bore to achieve higher displacement in c.i. While it's not a problem to increase the bore of an iron block, the LS1 is an aluminum block with iron "sleeves" inserted into it. To increase the bore, you have to put larger sleeves, hence the term "re-sleeving".

A popular setting here is to re-sleeve an LS1 block to achieve 4.130 inches of bore, and at the same time, to stroke it to 4 inches, resulting in 428.69 c.i. (commonly called a "427").

Re-sleeving an LS1 has been proven in the past to be less reliable than just stroking it. So, many guys will swap their LS1 block for an iron 6.0L block. Bored to 4.030 inches and stroked to 4 inches, that will give them a 408.

In general, if you increase the bore, you will net more horsepower at high RPM. Your engine will be able to spin faster because your pistons will have to travel a shorter course than in a stroker engine. This type of engine is better for drag racing, where your engine only operate at high-RPMs.

However, a stroker will give you more torque in the lower RPMs. Increasing the distance between the crankshaft centerline and the rod journal centerline is like using a longer lever to lift a weight. Strokers are better for street engines, where you're always in the lower RPMs.

Well, that's almost all. And of course, to answer your last question, the more displacement in c.i., the more power you will have

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Eric D.
99 Firehawk M6

waterbug1999

iTrader: (3)

Thanks for all the info.. TSP has a LS1 block for 600, guess i will start there. Wonder if it comes with the sleeves?

Blue Hawk

At $600.00 i'm sure it will come with stock sleeves. The cost of re-sleeving a block is much higher than that (in the 1500-2000 range i think, but I'm not sure).

Good luck with your project! And don't forget to upgrade the rest of the car. Sub-frame connectors, torque arm, heavy duty driveshaft with a safety loop if you drag race... and of course, get a 12 bolt or 9 inch. differential (your stock 10 bolt won't survive very long at the track with a supercharged stroker).

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Eric D.
99 Firehawk M6

waterbug1999

iTrader: (3)

Curious, If the LS1 block comes with stock sleeves will i have to get it re-sleeved when i put a stroker kit in it? Or can a 383 kit use stock sleeves?

Oh yea, in time im planning on doing the 12 bolt and all..

Blue Hawk

With a stroker, you don't need new sleeves. The 99+ LS1 can be overbored to a max of .010 inch. (in 97-98, .003 only because the sleeves where thinner). By just doing a little .005 clean-up of the stock sleeves, and putting a 4 inches stroker kit, you will have a 383. In fact, if your engine is still running good, I would'nt bother buying a new block. The best way to do it is to put a stroker kit in your stock block and have you stock heads ported with bigger valves, along with new intake, injectors, oil pump, timing set, camshaft, hardened pushrods, stronger valvesprings (very important!) and a good computer tuning. You already have the long tubes and exhaust.

I know that Lunati, Eagle, Callies (and probably others) make stroker kits. The part numbers for the Lunati kits are:

EA034-383 (with a compression ratio of 8.5:1 for supercharger applications)

EA035-383 (with a compression ratio of 10.6:1 for naturally aspirated, pump gas friendly applications)

EA036-383 (with a compression ratio of 12.5:1 for race-only applications)

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Eric D.
99 Firehawk M6