I'm debating on whether or not to pull the motor. I'm going to get a second (and maybe third) opinion, but I might be looking at a knocking rod in the LS1.

Let me say that I really like the LS1, and while I'm not opposed to putting an iron block in the truck, I really like the aluminum block--and I already have it. I guess I'm looking into a few options, none of which are looking too promising right now:

1) 348: 3.905 forged pistons, stock crank and rods
2) 383: 4" Eagle crank, 3.905 forged pistons, stock rods
3) 408: package from HPE (forged internals, iron block)
4) 294: put the 4.8 back in w/ a cam and a few more bolt ons.

I'm sure that a forged 402/408 would be ideal, but I'm not sure that I can fork out the cash for one right now (or any time real soon.) Getting the crank and pistons seems cheaper, but would I get eaten alive at the machine shop to rebuild the LS1 w/ the new crank/pistons? Would forking out the cash for forged pistons even be worth it if I'm going to keep the stock rods?

I'm not 100% sure that I even need to pull the motor yet, but I'm trying to prepare for the worst. I hope to God that I'm getting worked up over nothing though. Anyone care to offer any suggestions?

 

Also, plans are still in the works for the drivetrain if that matters:

stock 80-e
TT3200HD Yank
4.10/Eaton

 

I know APE has forged 370s (iron), or forged 348s (alum.) for $2,700. And then you can get a comp custom ground cam for an additional $250.

If you are tight on cash, stab the 4.8 back in, and stroke your ls1, and slowly add forged internals as money comes in.

 

That would be my vote. If absolutely neccessary drop the 4.8 back in and stroke the LS1 as time and money permit. It'll take some time and once again more money, but that will be a bad setup!

 

I'm having a little trouble finding dyno results on 383's...is there a reason that they aren't that popular? I guess most people that have $2800 to blow on an engine have the extra $1000-1500 to spend on a 408?

I would hope that a forged H+C 383 would put down in the 400-450rwhp range w/ the 80-e and 4.10s. That, plus a little bottle, would make for decently quick truck.

 

Hey dooood.

I was reading this. HPE is a good place to look. Thought you might like to read this. What I'd do if you have troubles with the ls1, is just sit and wait on a good deal at the sponsor sale forum. Find you a good deal and pounce on it.

347 w/ AFR 225's, custom cam, long tubes, and LSX

Good luck man. Hope its nothing

---btw. don't be stealing no good deals away from me. i wanna new motor toooooo

 

I just dynoed my "iron" 383 with horrible results ( due to me using a 01 Z06 cam tho ). You can easily get 400+ HP for about $3000 if you are patient with parts and do some of the build yourself. SLP has a bad rap sometimes but the short block 402 motor for $3995 is hard to pass on.
You also hit the nail on the head about the extra cost for a 402/408 motor. They are becoming much cheaper and as we all know the internal parts for the GenIII motors are very interchangable. Even better the LS2/7 engines will soon become more available.

 

Other than putting the 4.8 back in, why not just stay cheap and get the 5.7 rebuilt. It's a good solid engine for you and you have everything you need to drop it back in and don't have to worry about retuning it.

 

This was a warranty motor. We checked clearances and had a machine shop check everything out, but I just have a feeling that there is something wrong with the block and/or rotating assy that is causing this tapping noise. It's the same type of noise that I was told the owner was reporting, and it was bad enough that it was replaced under warranty if that means anything.

Depending on what happens, I guess I'll just have my block checked again, and get the crank checked out and the rotating assy rebalanced. I just figured that by the time I did all of that, I could have more than 346 cubes if I went with a short block from a sponsor.

 

obviously it depends on what your feelings are, but I would go with one of those new shortblocks and throw your LS1 heads on there. Then get that tranny up and running and get it tuned!!
That LS1 was cheap and got you some experience in doing the swap. Go for soemthing special as opposed to dumping money into something that may have an inherant problem. Not good when you are trying to get that thing to run.