So I recently bought my 4th F body 98 trans am A4. The car is very solid and in great shape including paint. It had to be a Florida car. The undercar is just so clean...Just high miles. 157xxx. but the engine is all stock minus loudmouth exhaust and slp lid and runs great. It still pulls with the original plugs...I've never owned one with this mileage. I need to replace the rear end with a new strange 12 because of bad seals and probably bearings. With the cost it's not worth rebuilding a weak 10 bolt. After that the trans performance build an engine with be done together. Now I want to add heads and a cam. Thinking I want the MS4. But the H/C I'm going to choose later on. Now my local speed shop guy was a GM engineer for 20 or so years and said the 98-00 ls1 blocks are different than the 01-02. Said they are weaker and for whatever reason (I forgot why) the blocks don't take well to stroking to 383. Which is what I want. I wanted 383 or I can go 402 with H/C and make some good street power. This car will be a garage queen/steet car with a very occasional track Visit. My question is it worth doing what I want with these miles on the block? Either way I will be doing new rotating assembly. I will be happy if I make about 400 or so to the rear. Maybe even 380 and a 100 shot. Nothing crazy. If I can't make that I'll settle for less and def go nitrous. Between my rear, gears (3.73), and tubular adjustable suspension, and nitto 555's , I think I'll have a nice street car. That's my goal. Price is on the table as it won't be done until next summer or even fall. I'll be picking at it here and there through the year. Now that being said I don't want to drop too much money in it. But I'm not cheaping out everywhere. (12 bolt, trans performance build) I was told I should go lq4. But then I have to buy a block and internals. I mean if this cost is similar I'll consider it. But it's also iron. The car will be NA, and I get good power after the build I won't even use nitrous. So I'm open to opinions. But mind I don't want to put crazy money. If I get enough people saying my stock block will be okay I'll use it. Just rebuild the internals. Or should I see of my compression is good and possibly just slap good heads and a cam in it? Save even more cash? My trans and rear will take it all day anyways so basically run her til she blows? Then I risk a rod shooting out and ruining the heads or something. I don't know. Sorry for length of the post just trying to say I'm down for anything that won't be too too much money. I have a family and this is just a toy but I don't want to have it apart longer than a year. Finish the car and be done with what I have. Then later on maybe build another setup. Thanks for reading lets hear your thoughts!

 

If you're going to get a block and rotating assembly and you're already thinking cubes, get a LS2 block. And go 4" stroke. 4" bore x 4" stroke = 402.

Before you go that crazy though, you can hit 400 on stock cubes much cheaper with a heads and cam package.

The 01,02 f bodies sometimes got the ls6 block which had siamesed bores. Hence the strength.

 

Ls2 aluminum 6.0? Don't know much about them. They come in gto's? Or was that the Ls6?

 

Then again this engine and my last one (that one only had 90k) it seems like my 157k isn't too bad. I see ws6s on eBay with 210k on the clock. Stock but still. Maybe I can leave the block alone. Of coarse I have to see what compression is. If it's good as it should be-previous owner regular my changed it- then screw it. H/C it is. And the following summer buy a new block for nitrous maybe even boost. This car won't be driven much so miles won't roll up either. I am also aware of how nice the lq4 is modded out but it is iron and don't want that weight. That weight means different springs too I wanna say. Springs were engineered for a specific load.

 

I would heads/cam the current engine and add the supporting mods to go along with it..

400hp to the wheels will be easy and that 98 block will take it fine.

It's all preference, hell you can cam it now and enjoy it while building another engine on a stand..

That way the car doesn't have to sit while you build the engine up the way you want it..

 

ive got a 99 with the ls1. I bored it over .004 (I know its almost no extra bore) and stroked it .250 to get the 383 stroker. I am pushing 468.1 rwhp at altitude in Colorado springs and the motor is having no problems at all. this motor started with 155k rough miles on it. These blocks are plenty strong as long as you don't bore out the iron sleeves too much. also be aware that LS1 motors have a pretty severe angle between driver and passenger pistons so stroking can stress the sleeves after time and abuse. If you want a power N/A motor you're likely lowering the lifespan of the motor from the 'standard' 200k miles on a rebuild to 120k or less. just what I've learned from doing mine so far.

As far as heads/cams, look at trickflow. they have good prices with some awesome packages.

 

The ls2 is aluminum 6.0. Came in vettes and GTO in 05-06. The LS6 was the factory improved version of the LS1. Came in the Z06 vette 02-04

The LS6 made 50 more than the LS1 due to better heads and cam. The ls6 blocks were often used instead of ls1 blocks in many ls1 cars.

Point is, you don't need to add cubes to an LS1 to make 380-400. That can easily be done with heads, cam, and intake much cheaper than adding cubes.

But if you're dead set on a 402, use the LS2 as a foundation, since it's already a 4" block. The ls1 should not be bored out to 4" due to the sleeve thickness.