I did a little looking around for info about this, but most of what I found is more drag oriented. At what point do yall consider splayed mains a necessity? Buddy of mine had it done to his car, 400rwhp. My motor is going to be making almost dead on that power level, due to us having the same class rules.

The difference between these cars and drag cars is that we are doing wheel to wheel road racing, normal hour and a half races, with us prepping to compete in a 13 hour endurance race. This motor I am building is going to live it's entire life at 4000-7500 RPMs. Splayed mains worth it? Or just stud the 2 bolts?

 

While studded 2bolts will be fine at that power level, going to 4bolt mains is not that expensive and is usually done "just because" since you're in there already. That way if you do upgrade in the future like 99% of people do, you wont have to go back and tackle the same upgrade again.

Straight 4bolt is an option as well, since the main caps should be a bit cheaper and on an LT1 I have even heard it may be just as strong as splayed on our blocks due to the amount of material around the main cap bolts in an LT1 block(no source for this, just old heresay). Keep in mind though that once you go straight 4-bolts, its a lot of work to go splayed and you usually just need to get a new 2bolt block to start with. That's why most just go splayed off the bat.

Again though, if you are sure that you only want 400hp since you will be class limited and endurance racing, then I would just go to studded 2bolt and save the cash.

 

That's not going to "fix" your engine...

 

What?

 

I'm planning on building a 383 for 500 horse, I'm interested in seeing what my machinist would charge to do spayed 4 bolt mains. Another option I have yet to research but you might want to look into is a 2 bolt girdle. I can't seem to find much about them on these motors, but that's what a friend of mine did on his Olds 403 build and he's probably pushing upwards of 400 horse.

 

I'm going to talk to my machinist when I get home and see what he thinks. If he says stud it and go, I'll probably do that. On the other hand, I feel like trying to save 500 bucks on a 20,000 build is kinda stupid. I guess I'm trying to find that line between necessary and overkill/wasted money.

 

It cost me about 700 to 4 bolt splay my block. Thats with a billet front main. Weston machines did mine, based in northern nj, works on alot of x275 motors

 

Was that just the cost of the machine work or is that including the caps?

 

That's what I spent on both caps and machining. Don't remember what caps I have though.

 

..then I wouldn't consider anything BUT splayed caps.

 

One small thing to keep in mind if you do 4 bolt splayed mains; you'll have to clearance the dipstick tube because one of the mains will prevent it from sliding in all the way.

 

With caps

 

No biggie, everything requires fitment and work on these types of builds. Thanks for the heads up, I can plan to expect that now.

Not bad. Looks like this is the route I'm going.

 

EDIT: Erased because I'm stupid, hope nobody had time to read that haha!