FWIW, I watched the teardown of a supercharged LT1 engine with WAY less than 1000 fwhp. One of the straight 4-bolt caps came off in two pieces. To be honest, it broke at an inside corner stress point. The engine was still running when it was torn down for a resize/rebuild with new splayed caps. The guy had dodged a bullet.

Another LT1 with well done splayed caps made it just past 1050-1080 fwhp when the block let go. The best caps in the world aren't going to make the LT1 block into a Bowtie.

From what I've seen up close and personal, I'd go 4-bolt by 500 rwhp. Splayed might be a little better than straight if they are installed properly. It's tricker to get splayed correct than straight, so if I were at all unsure about the block builder, I'd stick to steel straight (studded) caps. Also, there's no way I'd push an LT1 block to 4 digit horsepower. I'd be using a $2500 Bowtie block long before then because I'm cheap.

 

FWIW.... I've done 2 bolt blocks a few ways....

1. Splayed with a stepped cap.
2. Cut for a flat 4 bolt register and 4 straight studs
3. Splayed with a flat 4 botl register

#3 is the best for these blocks IMHO if you can do it right, took some time to find that out too. IF YOU ARE GOING TO DO IT, DO IT RIGHT!

Either way #1 and #2 are stupid strong with some hard block anyways.

Then again what do I know? I'm just a dumb Yankee.

Bret

 

That's pretty bad considering that George Baxter was using a 4-bolt LT1 block (not splayed) for years running 1000+ fwhp with forced induction and never had a problem holding the fastest LT1 record before he finally changed blocks and setups.

Mike

 

You must build him some pretty stout shortblocks, Mike. Congrats!
Why did he change blocks?

 

I didn't build his motor. Second Street Speed built his car.

I believe he changed blocks because he was after something even more radical (8s), which would push the LT1 (LT4?) block limits too much.

Mike

 

Too bad a 1100hp N2O motor and a 1000hp Blown motor don't have the same cylinder pressures and loads...

Thank god I didn't build the motor with the broken cap! I did get the bad fortune of telling the owner the block was basically useless now.

Bret

 

I only do #3, its about a 4-6 hour job on manual equipment, and hardly any time at all in the CNC one you have proven the program on another block, change the offsets and walk away. I like the flat cap because pulling the register out to the pan rails puts much more strength in the setup than the stepped.

 

 

Slightly off Title topic, but is there any way of telling what kind of block a car has in it, without pulling the oil pan off and looking? Any kind of conversion for block numbers, or vin numbers....that can be seen while the engine is still in the car?


Nevermind...I believe I found my answer here as long as the info is correct...
http://web.camaross.com/forums/showt...ight=bolt+main

 

thanks for the info everyone i just found what i was looking for