Doubt the block or not, Cantonracers isn't a direct representation either. That engine has roller rockers, and chrome valves. Plus that engine I took a pic of cost GM 40k, so nah, nah!!! I don't believe I ever said ANYTHING about being a spot on representation of a stock LT1/LT4. Just offered up a pic for comparison sake.

Plus, isn't that clear opti schweet!!!

 

I actually did alot of research on this last year.

To get a Reliable bore that size out of an LT1 you would need to sleeve all the Cylinders. This drasticly raises the price on doing a block as you want to do that work first and then after you braze the tops and bottoms of the sleeve so they do not leak you can do the rest of the work.

Unless you are going with REALLY big vavle and heads that can flow the return ,IMHO, is not worth the investment. I was looking to do it so my 18* heads would work better with 2.15 valves I also was shooting for a 427 LT1.

After monthes of research I decided to save money and build 427 Bowtie block 18* motor instead.

Untill I can finish it I am going to just finish another LT1. I already have almost all the parts so it cost less. now. The Bowtie blocks are about $1,600 and we were looking at over $2,200 for liners and machine work to finish the block. Plus then I needed to have the 18* heads converted.

In the end it CAN be done. The question is how much do you really want to send

 

I have a stock 4 bolt LT1 block sitting in my garage with the freeze plugs removed. I wish I owned a tool that could measure the cylinder wall thickness. Like a caliper?

 

The device used to check cylinder walls thickness is an ultrasonic tester.

Rich

 

I had my initial doubts about a larger bore on an LT1, hence I why I posted the question here. Also had a gut feeling I was trying to be a little greedy on the cube issue...more is better right?

As I stated in an earlier post, my dad told me that he personally had taken an LT1 bore out to 4.300" to put a sleeve in it a few years back. He stated that it did not go thru the cylinder walls. I know now that he was talking out his ****.

I dropped my LT1 block off last Saturday to have Milodon billet mains put on it and at my dad's swearing that there would be no problem with the boring.

Call Wednesday to see if they had a chance to work on the block. Hmmm....4.300" bore with no issue...again, my ****...they took it to 4.125". It cracked the cylinder walls in two seperate bores and in one bore it cracked the block between the bore and a head bolt.

Now the cracking of the cylinder walls...I can deal with, I can sleeve the motor and have put at .030"...but the head bolt issue...I am not comfortable with that at all. The guy at the machine said I was going to hard block it anyways...at least that is what my dad told them...hmmm...jeez...is my dad helping me or hindering me? Myself and the old man are going to have a little talk about these things....

Anyways...the same shop has a LT4 block that is totally done...torque plated, honed, line bored, etc...the guy never picked it up and they can't get a hold of him...been two years now so I think I can pick it up for like $400...maybe have the Milodon caps put on it for a few extra $100.

Thought I would share my experience...

 

Sorry to hear about the block. Its a good learning experience.

 

I have serious doubts about a shop that would even try to take the block out that far without either telling you that doing so will almost certainly destroy the block. Alternatively, to use an ultrasonic tester and get actual measurements to go by.

This is not cutting edge stuff, as small block Chevys have been around for so long that this kind of thing should be common knowledge.

Rich

 

I too have doubts with this shop also.

Things happen and I don't have a problem taking a risk in an attempt to do things a little different...unfortunatelly, a decent block got toasted.

Should make for some interesting phone calls today...

 

I ended up just get an LT4 block, .030" over, decked, torque plated, honed, new cam bearings, Milodon billet steel mains, line bored....basically completely complete for $776.50 out the door.

Thought I would put an ending to this thread with my solution.

 

How did the "talk" with your father go?

 

okay, sorry for the delay. i went over to more performance and the few blocks they have lying around ARE indeed bored to 4.125 . they are also sleeved, they said no way without sleeving the motor. the 7 motors I checked out were all bored to 4.125 and all had 4.00 cranks in them (427s), lots of titianium! They had one of there 427 blocks on the engine dyno and it put out 700 NA! Thats pretty nice in my opinion.

-Eddie

 

Do you have a phone number for More Performance?? I'd like to talk to them.

 

Hell yeah! I want to know how much one of those blocks cost!

 

Were those LT1 blocks? If so, that makes no sense to me whatsoever. But it isn't my motor, so who am I to say?

Rich

 

I was thinking the same thing. The LT1 bores are measured the same on center as a SBC chevy 400. The 400 has a 4.125" bore. In order to achieve it Chevy had to siamese the cylinders. That means the water jacket between the cylinders is eliminated and the cylinders actually share a wall.
Even with the siamesing, the 400 has thin cylinder walls.

In order to make a LT1 a 4.125" bore, you would need to completey remove the cylinder liners and re-do the block with siamesed sleaves. How is that possible?? I'd like to see pictures.