383 stroker quetsion

So here is my question, i have a 95 LT1 Trans am that is in the process of a major facelift, the motor is the only thing stopping me from finishing the project and ive come to a grinding hault ever since i pulled the oil pan off and seen only 2 bolt main caps :frown:. I plan on doing a 383 stroke to the engine but im not sure what to do about theses damn caps. I guess what im asking is what would you do if you were in my shoes?, would you just continue with the 2 bolt main LT1 block, find an engine that is already 4 bolt main, or get the LT1 splayed and caped as a 4 bolt main?. At the moment im leaning towards keepin the block and having it machined to a 4bolt. If anyone has ever had this done or has an estamate of where you can purchase the caps for doing such a modification please let me know, and also how much you think it would be to have the block splayed and line bored if new 4 bolt caps are the way i go. thanx alot for ur input.

you can have a machine shot drill and tap the other holes and turn your engine into a 4-bolt main engine. it's not very expensive, and doesn't take very long. i don't know the exact figure but i'm guessing $500 would cover it. (correct me if i'm wrong)

Thats what i figured as well price wise, im just not sure where the hell i would get the caps

Thats what i figured as well price wise, im just not sure where the hell i would get the caps
Just go with the splayed caps if you are intent on having a 4 bolt main. You can pick them up at Summit.
On the other hand, if you aren't going forced induction or N02, the 2 bolt mains will work just fine.

The 2-bolt mains should be fine. Some doubt there reliability, but I've heard of people with a 383 stroker and not worry about the mains. The corvette LT1 block has 4 bolt mains if you want to find one of them.

for now im just going to build the rotating assembly, cause its all my budget will alow, but eventualy i would like to go forced induction, so id like to take car of the 4 bolt main problem now so ill have the room to expand in the future. i have also heard stories about the splayed aftermarked 4 bolt conversion not being a good choice because of the caps walking, but ive also heard that a 2 bolt block converted to a splayed 4 bolt is stronger than an original 4 bolt because of the way the bolt holes are machined into the area under the oil pan surface. What do you think?

Yes, splayed 4 bolts are stronger than OEM 4 bolt mains.

2-bolt mains are decently strong, but 4-bolt mains will always be stronger (when comparing 350s) they allow you to rev higher, they can hold more power/torque and they add reliability and durability.

splayed 4-bolt caps, some drilling/tapping/machining work and you're all set for a lot of power and a lot of strength.

after a bit of reading an research, it seems that most machine shops want about $600 for an all-in 4-bolt conversion. that includes the machining, the caps, studs and nuts. usually the 4-bolts have the two outer bolts/studs splayed at 10 degrees.

you want line boring and line honing.

ideally, you want all this done:

http://www.chevelles.com/forums/showthread.php?t=93124

i know it's a link to another forum, but it covers everything.

for now im just going to build the rotating assembly, cause its all my budget will alow, but eventualy i would like to go forced induction, so id like to take car of the 4 bolt main problem now so ill have the room to expand in the future. i have also heard stories about the splayed aftermarked 4 bolt conversion not being a good choice because of the caps walking, but ive also heard that a 2 bolt block converted to a splayed 4 bolt is stronger than an original 4 bolt because of the way the bolt holes are machined into the area under the oil pan surface. What do you think?

Well, if you're going to be looking for forced induction now, it would make sense to go ahead and go the 4-bolt route. The only problem is, how much boost you'll be wanting to run later. Because if you build it for N/A power now, you'll have to change some things later to accomodate the boost.

the best solution is to build it as strong as possible first time round.

that way it's more durable/reliable and has the strength should you want to make more power in the future. and it's cheap in the long-run.

I was going to build a 383..........that is.....until a guy said "Why don't you just build a 406?"....I was like, "Why".....He said I would spend the same amount of money, and get much more. Now, I have spent way more money, but I know it will pay off in the end........


Don't do a LSx motor............................EVERYONE has one of those!


Just a suggestion!

Well, 400+ci on an LT1 small block is not an easy task. It takes a lot more work than an LSx block. And why not an LSx block? The new LSx block released by GMPP has promising potential and is probably more reliable than most other blocks. And the range of displacement potential covers a huge range to fit almost any application.

Well, 400+ci on an LT1 small block is not an easy task. It takes a lot more work than an LSx block. And why not an LSx block? The new LSx block released by GMPP has promising potential and is probably more reliable than most other blocks. And the range of displacement potential covers a huge range to fit almost any application.
I don't have anything against the LSx motors........it is just,,,,everyone has one, or is building one.