I'm planning a 355 rebuild on a LT1 and run 100-150 shot of NO2, adding Lloyd Elliott LT 1 heads port matched to a LT1 intake, & CC306 cam. My NA goal is approx 400rwhp. I found what I consider to be a really good deal (maybe it isn't!) on a rebuilt, balanced and blueprinted 4 bolt main LT4 short block w/ SRP/JE flat top forged pistons (.030 over), GM steel crank, and powdered metal rods for under $2000. It does have 1 piston/cylinder that is .040 over due to a bolt dropping in the cylinder and damaging the wall. This shop opted to rebore as opposed to sleeving the cylinder.

My questions:

1. Will this short block work w/ my heads, intake, etc?
2. Will the unvented opti work w/ this short block?
3. Will my Hooker shorties fit this short block?
4. What other negatives/positives might I encounter?
5. Is this NOT a good idea?

Hopefully I've provided enough info for my questions to be answered.
Thanks!

 

All LT1/LT4 blocks are the same. What works on one will work on the other.

 

The LT4 used a LT1 block with the 4 bolt mains. The corvettes all used the same 4 bolt main LT1 block also.

 

So far the LT4 block mating w/ the LT1 heads/intake/headers looks ok. What about the other issues? The single piston that is .040 over? The pm rods w/ the 100-150 shot of NO2? The unvented opti (I prefer NOT to convert)?
Thanks!

 

Again, there is no LT4 block. Its a LT1 block with a 4 bolt main! What made it an LT4 motor was the LT4 heads, cam, and intake.

Not sure what to say about that one piston being .040 over.

The PM rods will be fine, even with a 175 shot. A lot of people have been running a 175 shot around here for several years with no problems. The later model LT1's had PM rods.

The non vented opti will work as long as you have the timing cover and chain for that setup also. I assume you already have this stuff from your old motor.

 

Thanks!! You're right, I do have all the auxiliary stuff from the old engine. The only nagging concern is the 1 piston. These guys are racers and race engine builders w/ an excellent reputation in the Dallas area and have assured me that the one larger piston is not a big deal. I just wanted a second opinion form the experts on this board. From what I'm hearing so far, this is a good deal for me.
Thanks!

 

You are right that there is no 'LT4' block.. it's the same as an LT1 4 bolt main block..

There is, however, more to an LT4 than 'heads,cam, intake'
[crank, pistons,rods, timing chain, main caps,etc]
Here's a good site that shows the differences..
http://www.malcams.com/legacy/misc/LT4.htm

 

you're going to run into a problem running that much nitrous in the engine..unless you go wiht a direct port nitrous system (one tube per cylander) you may get some cylanders running lean or rich, depending on how much nitrous goes into each cylander if you go with a wet or dry system ..the problem with that one cylander that's different..is assuming your system splits the nitrous up evenly, if your fuel pump accomidates for extra oxygen(n20) then that cylander should run a bit leaner due to having a bigger bore..with the direct port system (assuming you're leaving the engine fuel injected)..you will get unparrallelled tunability..but it's a little more complicated..and im assuming with the work you're going to be doing..you'll eb able to figure it out..sounds like a bad@$$ block man, good luck

 

I spoke w/ my mechanic friend whose opinion I trust unconditionally and he advised me against the block. He questioned the 1 piston not being the same and said I was asking for problems, especially since I want to run NO2. Thanks for all of the responses. I learned some things and will be a better informed consumer!
Thanks!