bjamick

iTrader: (31)

Ok well im bout to head into an MS4 cam swap with the springs, pushrods, and you know all the good stuff. Well im not for sure how long a 109k mile bottom end will last @6800rpm SOOooOOO i am now bout to start a forged fund LOL. I will be atleast spraying a 200 shot and most likely will be a 250 shot. So should i go with the big cubes like the 383 or should i jsut buy the forged rods and pistons and do all new bearings and all that good stuff for the 347?

I know the stock crank is good for a pretty good amount of horsepower so im not really worried about it, one thing im worried about is slinging the rod through the side of the block . I figure i start getting all the parts i need now so when i get everything i need i can just pull the motor and take it to a machine shop and get it cleaned honed and all that good stuff and then just put all the new parts in.

If you guys could let me know do you think it would be worth it to go with the 383? If ill only gain like 2 tenths from a 347 to a 383 then ill just save the money and go 347 but if it will be like a .5-sec drop then ill go 383 but if you guys could just please help me out and let me know your thoughts.

Thanks
B.J.

darrensls1

If you're gonna do it then may as well do it right. 408 LQ9 iron shortblock built for N20 would run about the same cost as a 383 aluminum shortblock. If the extra 80 pounds bothers you too much you can also consider a forged 402 LS2 shortblock. LME quoted me $3900 for my choice of 383, 402 or 408 with the ability to handle 700 rwhp on N20. Of course the MS4 cam would then be considered a baby cam for either of those shortblocks

If the whole setup is right then you can run high 10's on motor and then spray a smaller shot (100-150) to reach your goals of low 10's. The beauty of this setup is you still run high 10's even when the bottles empty. It also leaves you room to grow into the 9's (bigger N20 shots and bigger cam) if you ever decide to make it a track only car.

Or

Just get a forged 347 for about a grand less then the 402/408 and spray a bigger shot to reach low 10's. But remember that the extra money you spend on nitrous will eventually exceed the extra cost of the bigger shortblock.

Good luck.

bjamick

iTrader: (31)

But im jus wanting to use my stock LS1 block, thats why i didnt even add the 402 or higher cubes bc then i would have to buy a block and all that good stuff. I know that the bigger cubes will run better on motor but if you take a look at some of the times the 347 is running right with the bigger cubed motors . This is why im just wondering about the 383 vs 347 just wondering how many tenths would there be between the 2 with just an eagle crank?

Boodyrider

iTrader: (2)

408 or 402. Cost is comparable to building your block, and typically no core charge/ no need to buy a block.

Cost on these has come WAY down.

And reliable low-mid 10s, this IS the way to go. (Or go low compression 408/ 402 with a little (big) hairdryer in the back, and go VERY low 10s, maybe as far as mid 9s and still streetable on lower boost settings!)

twokss

iTrader: (5)

im in the same boat your are. i have the same mid ten goal...im going with an iron block 370 setup for spray from tsp. its a really low cost bottom end, for what you get.

30thanniv

iTrader: (2)

Have you even gone 12's yet? or 11's?
If not seriously reconsider what you are aiming for.

bjamick

iTrader: (31)

Ive got an 11 sec car right now but i am only spraying a 100 shot. im just worried about the bottom end of the LS1 bc ill be spinning it really high. really dont wana go Iron bc of weight so thats the reason i was just gunna go with the original block bc i know it will hold up to the spray.

So lets just keep with the aluminum blocks and save the weight.

Ericbigmac83

iTrader: (19)

My fiancee, "why would you wanna go smaller"

If your choices are 347 or 383, i would just forge the 347. If your choice was a 402 or forged 347 then i would say go with the 402.