6th gear

http://texas-speed.com/p-678-tsp-421...ong-block.aspx

Thinking about going this route for my next engine build. When my stocker gives out. I am looking for something with large cubes and makes a *** ton of power, on a budget. LOL
The engine will be going into a full weight 2004 Pontiac GTO,6 speed,with 3.91 gears. I will be street driving this car as well as the occasional run down the track. I am unsure if it will be a DD at the time the engine is built.

I was planing on useing the PRC stg 3 LS6 heads, a Victor jr intake with 100mm TB. There are several things that i am still unsure of.
Cam?
Valvetrain?
Fuel?
I am looking for around 600 rwhp.
What are your thoughts? What would you recomend? Thanks guys.

lsx24

iTrader: (45)

You do know that's an iron block right? That might be 100-200 lbs. heavier, though if you're willing to absorb the weight you should be good with gears. You'll probably have difficulty getting 600 to the wheels, but if you can, look out because that sucker's going to cook.

6th gear

Yes i realize the added weight. And from what i have read 600 rwhp is verry easy to do with these engines. But i need to look at this in a more logical way. I am not building a drag car. I am building a all motor street car. But also something that i can take to the track and put down some good times. So that being said i am sure that i will be sticking with a hyd cam and not go with a solid cam. Im just not sure of how big or small to go. I relize that its a large bore and c.i. so i was thinking something with a med duration (230-250) and something with alot of lift (600+).
I was also planing on use a LPE 225 fuel pump bu i am not sure of what size injector to go with.

fatmat80

I think you should rethink those heads. I would look at getting the PRC 227 at least. A cam in the 240s should get the job done and still keep it streetable for daily duty. You could always keep the cam on the smaller side and hit her with a little juice. I would do a 42lb-60lb injector as well.

Sales1@Texas-speed

Give us a call or pm. We will be happy to help you out with your setup.

Sales2@Texas-speed

iTrader: (5)

600rwhp is definitely not the norm from a long-stroke iron block unless you add the extra bore size and go with the LSx bowtie block. At that point you can run the LS7 heads and really start to extract the power you want from it, but with that relatively small bore size on that 421, you are a bit limited in that regard.

lsx24

iTrader: (45)

The problem with long stroke is RPM limit. Yeah it's easy to pull killer torque numbers but it will run out of breath at just over six thousand. You want to pull a serious number then I would bore and stroke it. With the better bore-to-stroke ratio it will also allow for better heads.

01ssreda4

iTrader: (96)

Try 80 pounds heavier....not 100-200.