been looking over various combos and want some outside input. i know i want to go solid roller, between 12.0-12.5 compression, and a single plane intake setup.... im up in the air about which cube LTx i want to build. 383, 396, or 408. i realize the larger cubes will provide me with more torque, but is it really worth the hassle and added cost of machining to go 408? i can buy 383 and 396 rotating assembly kits at a fairly affordable price, but would have to piece together a 408. any thoughts? really looking for some experienced opinions on this matter. thanks in advance.

 

383 is plenty of cubes IMO

 

Completely depends on your goals. When you get into the 400s on LTs you are looking at some big money where as a 383/5/8 will be more affordable

 

396, more more uncommon than 383 or 355.

 

A few years ago it was a lot cheaper to build a 383 than a 396. Nowadays you can do a 396 for just a little more. To my knowledge there are no cast cranks available to do a 396, you can find cast cranks to build 383's if you go that route. Since you want a solid roller and a single plane, i'm assuming you want to spin the motor high so a forged setup is the best choice for you. I would go for a 396. As stated previously, a 408 is VERY expensive. It requires a lot of block clearancing, small base circle cam, special rod bolts, etc, etc, and I doubt you'll get the longevity out of it that you would with a 383 or a 396. If you have a problem with a 408 there's no room for a rebuild. It becomes a boat anchor. Contact Clayton Racing on here and ask them their opinion on the different cubic inch LTx motors that they build.

 

I have had both a 383 and 396.

I prefer the 396. Just my opinion. They can both work well. Head and cam choice are key among other things.

 

i realize that regardless of what i build to turn high rpms im gonna drop big coin on the top end. i noticed that i can do an eagle rotating assembly for a 396 for about the same cost as a 383. anyone have any input on the eagle brand of stuff? i know alot of guys are fans of callies, and some like scat stuff. what seem to be the best/ least problematic of all brands?

 

oh, tony, one other question for you since you are kind of an LT1 guru..... what length connecting rod would you run in a 396? i see lot of kits have 6" rods but you can also get them with a 5.850" rod.

 

408. Its not big money despite what everyone thinks
Talk to karl ellwein

 

Anything above a 396 and you start wasting money IMO. It's definitely a diminishing return and it's more of a novelty than an actual performance advantage. A 383/396 is plenty IMO.

 

like ramair said 383/396 is plenty

also if you decide on a solid roller which will likely see alot of RPM make sure whatever you buy the rotating assembly has a very good balance on it.

 

you will struggle to find enough cylinder head for a 4.00" bore at 396+ cubes, the rpm won't be there and you could actually make more power with less cubes. The fastest N/A LT1s have all been 383s.

 

how much money you got to spend?

 

I'd say whichever's cheaper/easier/STRONGER of them.


Karl has built you a 408?! Awesome!

 

Ls you must not like greg so much hu?

 

well im really trying to stay under the 3k mark for the short block. need that money for the top end. more specifically the heads. not something im doing right away, just want to take my time and get it all mapped out before i start buying anything. dont want to jump in both feet and realize i spent money where i didnt need to.

 

No we're best friends.

This is me trying to get him to come swimming with me. Don't know who the kid is.

 

that is just wrong.....

 

lol that just made the hole week. Gregs post are almost as funny

 

3K for a 408ci shortblock is unrealistic. The machining costs would be somewhere close to 1K including filling the block, so that leaves you 2K for a very uncommon forged bottom end. Id either expand your budget or stick with a 383/5