LT4 Complete LT4 rebuild soon, soliciting informed recomendations.

[RPM's96]

I am looking to spend about 5K+- on a complete rebuild on my 96 LT4. My mechanic and engine tech will be collaborating on this, I am not a motor builder by any means and this will be the first time I have spent this kind on money on a build. I am counting on them to find balanced parts for a motor that will be a significant improvement over stock for use as a frequent durable driver, not raced, but spirited driving form time to time. The whole rotating assembly will be new, valve train, .060 over, hot cam, possibly some head work and MSD Ignition.
I am in CA so it needs to pass smog here :ugh. I am thinking I cannot get the most out of the motor without a tune. Will this be a problem as far as smog goes? Any way around it? Any good tuners in the central CA area?
Also (separate budget) will have a (Center Force probably) clutch installed.
I have seen varying opinions on MSD ignition vs stock opti.
Parts recommendations/combinations including clutch. I had thought of going steel flywheel instead of the stock cast, but was advised not to cuz it is a minor improvement. Don't want aluminium.
Also I am wondering if there is anyone in the area that can work on the ZF6. My mechanic says he has only heard horror stories about those that have tried. I know about the ZF Doc. Just wanted it freshened up. It is shifting ok, but has 70,000+ miles on it (like the car) and as long as everything is apart...
I hope to tap the deep well of knowledge here and would love to hear from those of you that have been down this road, and may have information about what has worked for you, or not, and why.
Thank you

 

[RPM's96]

Too much?

I guess I was asking for a lot for a member that has only posted once before. Ah well, I will keep checking. I think I have an exceptionally well qualified builder and will not be disappointed. Hopefully the build will commence this month and be completed by next month, and I may be to able to contribute something to the LT4 community instead of appearing needy.
Still hoping to get information on what clutch brand and type have proved most durable and appropriate for use with a DMF or perhaps a steel fw on a motor that I hope, between the extra cubes and the cam + other upgrades will make 380 or perhaps a little more hp. Leaning towards Centerforce Duel Friction #DF100130 clutch and pressure plate. My builder questions my sanity for putting that much money into this car, but it is either do this and have a car that is paid for and running like a scalded cat, or buying a much newer car and having to spend an additional $25,000 - $30,000 to get what I want. Love my LT4 CE.

 

[Hib Halverson]

With only 70,000 miles on the engine, there is no need to replace the crank, rods and pistons. I'd inspect all the pieces, have the crank and rods all mag'ed. If everything looks and tests good, I'd reused them

I would not go .060 over. That really thins the walls. I'd go .030 at the most, and only if you need it. Have your engine guy measure the bores to see what level of wear is present before making a decision on over-boring the block.

The GM Hot Cam will bring that engine to life, for sure. Add some head porting and you'll be at the 400-hp level even with the stock manifolds and cats you need to keep for the Smog Check.

The MSD abits distributor would be a better choice than stock.

You are correct, you'll need a good tuner to recalibrate for the Hot Cam and the head work but, also, to keep the engine emissions legal.

The nodular iron flywheel will be ok but an aluminum wheel would be a better choice. Also, on the clutch, think about McLeod rather than CenterForce.

If you're going to send your ZF out for work, the ZFDoc is the best choice. That's who does my ZF work.

 

[RPM's96]

Thanks for the reply Hib.
The motor has some knocking upon startup that my mechanic feels is wrist pin or skirt damage. That is the reason for the new pistons, and what got me thinking about just doing the whole motor.
As long as it has to come apart anyway I want to do it up as best as I can since I find myself able to afford to at the moment, and I have always wanted to do this.
The .060 was his idea, These guys have been racing for generations and first thoughts are more cubes and turn it up lol. The guy doing the build is going to determine what needs to be done to put together a durable, balanced motor. I trust him to know what to do to turn it up without blowing emissions requirements.
I see you are in central ca. Do you know of a tuner you would recommend? I will look into McLeod, and reconsider an aluminum flywheel.
Do you have knowledge of/thoughts on the head and cam packages offered by Advanced Induction or Elliott?
Thanks for your thoughts.

 

[John Mekisich]

LT-4 Rebuild

$5K seems pretty reasonable for a complete rebuild considering the amount of labor involved in doing the work. I can understand your mechanic questioning why you would want to drop so much $ in it. The value of these cars has been flat since I acquired mine back in 2002. My concern with modifying it would be maintaining smog legality. Is it known for sure that your car built as outlined can be tuned to pass smog? It would suck to build it and have it NOT PASS emissions. Mine barely passes on NO as it is. Just my 2 cents worth................

 

[RPM's96]

Hi John. I am concerned about maintaining emissions compliance, it is a priority. There are a few things that can be done though such as the hot cam and porting, balance and blueprint for starters.
I have thought long and hard about putting the money into this car. On the one hand I could sell it and use the cash on hand to car to buy another car, but the next car I want would be a 2009 or later C6, or perhaps a C7. I cant make that happen without taking on payments, and I don't want payments at this point.
My car is still clean and tight with fairly low miles. I can spend a few thou on my current car and have a paid for car that is still be fun to drive while I wait for the right time to upgrade to my next Corvette.
I am still waiting for my guy to clear a bay. He is swamped. I am itching to get it done.
Heading to work. Have a pleasant day all.

 

[RPM's96]

Came to a different solution. Sold the LT4 and got a low mileage C6. As much as I liked the C4, the new car is SO much better, and now I am out of the C4 rut I was in.

 

[John Mekisich]

LT 4 Rebuild

Came to a different solution. Sold the LT4 and got a low mileage C6. As much as I liked the C4, the new car is SO much better, and now I am out of the C4 rut I was in.

That is certainly one way to approach this however your original goal was to have a car that is paid for. I have considered doing the same upgrading to an early C6 ZO6 as there are plenty of them for sale. What stops me is the cost difference plus having to absorb sales tax/registration which can be a significant added expense. In addition, many low mileage C6's still wear original tires that will soon need to be replaced due to age regardless of mileage. Just my 2 cents.............

 

[RPM's96]

John I know exactly how you feel, however I am glad I made this move in spite of the modest payment I have now. While I liked the more raw feel of the 96, the new car is so much more capable in every area.
I drove it to Bakersfield last weekend for the Showdown and the 460 mile round trip was effortless. The cabin noise was far less, stereo worlds better, (never used the radio in the 96) seats with fewer adjustments proved more comfortable with superior lateral support. The suspension inspired confidence while being much more comfortable. The car felt planted in a way I have not felt in anything I have driven previously.
And the LS2, wow. A friend who races late model cars said it felt like a race car, both power suspension. Hi praise from a track champion.
It had 2 new f1's on it and the other pair still good for a while.
Not a fan of automatics in a corvette, but I can live with it. Thinking of getting the DS Trinity to firm up the shifts and who can turn down a few more hp? Going to look through the forum to see what others think about them.

 

[RPM's96]

Gone, not forgotten


Going to miss this one. Somebody got a sweet ride.