ToyC4

My LT1 spun a rod bearing after putting the top end back together. I was quoted $4k by a local shop to pull the engine, rebuild it, and put everything back together... I think that sounds reasonable but ...
What performance modifications should I make while the engine is apart? I'm planning to go .60 over. I want to do the GM LT4 hot cam kit and If I can afford it I'd like to throw on some long tube headers.

But I'm also thinking about doing a 383 stroker which my local shop said they can do for $6k. My local shop will do a full 12 month 12k mile warranty on either build uup.

I'd just like some opinions before I run out and spend more $ on my car. I know a lot of you guys have been there and done that with projects like this ... ... ... ... I just want to know what the best performance and reliability for my money is going to be.

thanks in advance,
Joe

mackeyred96

I'll bet you never per oiled the motor after putting the motor back together and spun the rod bearing.

ToyC4

put in oil and let it idle 20 minutes before taking it out to drive it, I think the oil should have been changed before taking it out because I think some crap that was under the intake that was cleaned up fell into the engine and plugged up an oil channel or something which caused the bearing to not get enough oil. Drove about a mile, opened it up and it started knocking. Needless to say I was sick when it happened and I still am.

mackeyred96

By per oiling you put a attachment on a drill down into the oil pump and build up pressure before you ever start the motor up.
This is a common failure.

larryfs

it is indeed a very common failure. usually within a few hundred or few thousand miles. People claim non-cleanlyness, people claim retorqueing the heads.

all I know is I won't touch my LT4 !! it'll remain all stock untill it blows up.

for the numbers you have been quoted, I'd get a crate motor...

Tony.96LT4

I don't even think about starting an engine after rebuild till I have oil being pumped out of every pushrod onto the rockers from pre oiling, but that's just me.

silver84

Toy, think 383.
Also, do you have thoughts about eventually using
a blower or nitrous?

larryfs

I don't think pre-oiling is an issue if only the top end was torn down.

It is just so common on the LT motors for some reason.

vettme

There is no replacement for displacement ,it will give you a great foundation to build on.Look at all of LLP's mods most of them start with more inches.Even GM is going largre in the C6... food for thought:}

70ZZ3 96LT4

A ZZ4 short block will give your everything brand new for a lot less than $4000 and a lot quicker than waiting on a machine shop to build an engine.

larryfs

also... there was a guy around here who spun a bearing at the race track. pulled the oil pan, replaced just the bearing and was done with it.

I know he was back at the race track again. I don't know if the bearing job held up??

Black 96 LT4 from NY or NJ.

I'd be curious to know....

ToyC4

Only the top end was torn down so pre oiling shouldn't have been an issue. I can get a rebuilt motor for 1-2k but the $4k quote includes removal from the car, complete tear down and rebuild with new parts at .60 over, re-installing the engine into the car, and a 12 month warranty on the engine. For $6k the same shop will do the 383 stroker motor - I guess it would be a 388 if it was .60 over? (The shop said three weeks from drop off to pick up which I thought was reasonable) I'm just trying to figure out what the best bang for my buck will be as far as cam or headers while the engine is out and torn apart. (I've looked at crate engines but I don't want to have to deal with wiring issues etc and I'd also like to be able to pass the car off as halfway stock when I'm done) If pulling the pan and replacing the bearings is an option I'd be all over it ... is this a good idea?

wildman378

Order you a 04 405hp ls6 crate....

Sunyi

I would definitely not just replace the bearing, as the big end of the rod would need alignhoning.... Not to mention all the debris after the spun bearing

You need to tear the engine down and do a complete reubuild.

Nathan Plemons

Ok, ask some questions and figure out exactly what each rebuild option is going to give you. Does this include ported heads? If not you won't see the full performance benefit, especially with the 383. If the 6k still has stock heads then I would do this.

Spend the 4k for the 350 rebuild and spend the extra 2k on heads and headers. This will ultimately perform better than the 383. It won't have quite the low end grunt but it will certainly pull better on the big end. Now if good ported heads are included in the deal than by all means go with the 383. However a good set of heads is really going to need the headers to thrive, especially in a stroker motor.

You may want to read this thread and see what all the different power levels are with different stages of the Hot Cam in a 350

http://forums.corvetteforum.com/showthread.php?t=869468

DieL

if i were you, id do all the parts shopping yourself. i could go back and do my 388 ( i went 60 over too! ), id do it on a real tight budget... id go with the scat cast crank ( $190 usd... good for 550 hp), maybe some decent steel rods, forged pistons ( in case you get bottle envy), BUT where i would spend MOST of the money is on the heads. Have them ported and flowed... spend extra here if you have to because it will decide how the car performs. Ive seen a 400 + ci LT1 that had heads he bought off ebay... and it was awful... oh and the same guy did the heads first... and whaddaya know... he spun the bearings within 50 kilometers from leaving the shoppe.

ToyC4

Thanks for all the good advice guys! Nathon it makes sense to do the 355 with porting the heads and buying long tubes from where I'm sitting because if I do the stroker I'll be too broke to do everything else right. Who makes reasonably priced long tubes?

I just wish I would have pulled the engine to rebuild when I first picked the car up 4 months ago because I've already dropped 4-5k on BS repairs and now I still have to have the engine pulled out.
it's just money right?

Nathan Plemons

There are plenty of choices for headers on the LT1. If you don't need to pass emissions than the Hooker 2151's are hard to beat on cost / performance.

There are people who will tell you that 1 3/4" headers are too big for a 350 and you should run 1 5/8" Don't buy into the hype, 1 3/4" are more more readily available and cheaper to boot. They will also give you all the room you need to grow later should you so desire. You might give up a little bit of low end torque over the 1 5/8" headers but you'll make it back up on the big end. If you do the hot cam / heads / 1 3/4" header combo you'll be VERY happy with the results.

ToyC4

If I plan to:
-rebuild engine as 355
-port and polish the heads with valve job
-put on long tube headers

Should I go with something more aggressive with the cam and rr than the LT4 hot cam kit? I want the car to be dependable as a daily driver if needed but I want to make sure I do everything right the first time I've got this engine apart and get the best performance and value for my money ... I really want a cam that will let me rev high so I'll have a good autocross engine.

Am I right in thinking that if I use 1 3/4" headers I can get my low end torque back by adding backpressure with the exhaust system?

GS345

Go bigger than the hot cam. Its a great sounding cam....there are just better cams out there...especially since your doing a 355. I have the hot cam now and it's forced me to do a 396...lol

jeff