Alright I am planning out my next motor for my 04 GTO. I currently have the stock LS1 long block with un touched heads and cam. Currrent mods are TVS 1900 @ 10lbs, 1 7/8 Kooks w/ catted mids, 92mm TB, Walbro pump, 4” hardcore intake.

My goal is to keep the cubes reasonable and optimize the set up with the TVS 1900. I am shooting for 700rwhp with Dart heads that have been ported and coated. I will have a custom ground cam from Ed Curtis. I will also be upgrading to a 102mm Nick Williams TB and a matching OTR intake or an equivalent.

I plan on running 93 octane with Meth for safety not tuned for more power unless I am headed to the track in which I will have a separate tune for it.

The car needs to be 100% street driveable and I do not want to think twice about driving it 500 miles. It will go to the track occasionally but will not be purpose built for this.

I would like to go with a 383 stroker however I have been told it is a bad idea with Maggie boost due to less material on the piston face and due to the stroke the piston skirt will tend to pull out of the bore more and cause it to wiggle more under boost. I know not very technical description but that is why I am doing my research. What are your thoughts on a LS1 based 383 with the TVS spun to its maximum efficient range?

Now when I researched the 383 on this site it seems a lot of people are using the 5.3l block and stroking it to 383. I can see the iron block being an advantage in this case but the boost of choice seems to be a turbo or centrifugal supercharger. Would this be a good option for a Maggied car shooting for 700rwhp?

My ace in the hole will be to shoot for a 6.0L LQ9 stock bore stock stroke with forged internals. But I really like the idea of a small cube stroker for that kick in the pants down low.

Any suggestions or help would be great as I am beginning to think a 383 would be plausible for what I want. Especially since it wont be raced regularly and will maybe see 10k miles a year if that…

 

I would give this a look:

https://ls1tech.com/forums/14258327-post4.html

 

I would go with a 402 or 408 iron block build. It will be the strongest and cheapest way to go, plus, the bigger bore only helps breathing.

Check them out here, http://www.schwankeshortblocks.com/s...?i=1497&c=1216

It is a link to the 415 page, but a 402/408 would be the same price for boosted applications.

 

Awesome...That is definitely an option and seems to address all the concerns I have with a 383 stroker.... Plus I could easily swap the 1900 to a 2300 and probably shoot for 800 rwhp...

 

I have thought about that but the 390 and then the 400ci+ strokers are going to dictate me spinning the TVS 1900 passed its efficiency range to keep it happy. The goal and challenge I am going for is smaller cubes with higher boost.

 

What is this motor rated to horsepower wise? Keeps cubes reasonable and would be a great street screamer...
http://www.schwankeshortblocks.com/s...?i=1494&c=1094

 

I don't think I would go over 8psi on the boost on the 388. I think you would be farther ahead just getting the extra cubes, and setting yourself up for the future rather than being trapped.

Plus, the bigger bore will allow for other head combos in the future.

 

I can see the value of going bigger for future modifications which makes it tough when my original plan was to stay with stock cubes and boost it to the max efficiency. However I could easily do this with bigger cubes which will put the blower past max efficiency needing me to go with a bigger blower.

Decisions Decisions....