Just picked up a new toy today. Got a 97 camaro that will be donating its LT4 to be built into something nicer.

Before you guys ask, yes, its an LT4. Not an LT1. Car is pretty much run its course, so Ill be repurposing its guts for my 95 vette.

Ill be making this one a 383 and the top end will be ported while its apart. I have another block ready to go, so I was curious what you guys have been using as a replacement for the LT4 pistons, or if GM has a p/n for an offering at .030 over? That way that rotating assembly can still see some use later on...

 

Would you mind posting your SPID for the car?

Listen, if it is what you say it is, that is a 1 of 108, or more specifically 1 of 100 available in the US. It is a very special car and to part it out rather than restoring it is a big mistake. I would venture you could sell it in it present condition (no matter how worn out it may be) to someone interested in restoring it, at a price that would finance your build for the 95 or cover the cost of buying a 96 and modifying it. Without destroying history.

 

If you are going 383, or a full custom build you can use any SBC piston you want that will meet the proper specs. I was just reading an article last night about tips on building a stroker motor and they were really big on buying a complete rotating assembly as a kit and not to do it in individual components. The kits solve the relationship between the stroke, rod lentght, piston height in relation to deck heigh, and piston measured diameter to the bottom of the bore.

There is also harmonics in play, Although a crankshaft seems like a very rigid component, it does flex under the varying forces. Each rotating assembly has its own natural frequency much like a tuning fork. Aspects such as crankshaft material, engine stroke, flywheel mass and bearing dimensions determine the natural frequency of a rotating assembly. So, unless you want to do a lot of homework and out engineer experienced engine builders, buying a kit that solves all of this is probably the way to go.

Since you are going so deep into modifications, I don't believe you need to worry about an LT4 specific piston. In the end, it is a SBC. You need to get a solid rotating assembly that works together.

That block casting number is probably going to be worth more than you will spend modifying it.

 

I of course understand your post but the OP never said/mentioned original to car. VIN of car or SPID of course answers question but maybe what the OP needs to be concerned with is the VIN derivative that's on the block. That would/should identify it's origin.

 

It is not original, and even if it was, the car is used up. I know the difference. So would my wallet if it was an original LT4 car. Compared to what a real SS LT4 car would cost, this was a drop in the bucket. I prefer to use base models for my more in depth projects...Im not one to willfully taint a special edition car.

I dont do kits. Never have. I like personally choosing components, and most of the time find something in them I don't like. I would consider them if Im allowed to substitute components, but usually I do my own thing. Theres no magic to it... and I think its more fun anyway. Gives me a little more control over the end product.

The 383 I already have the rotating assembly for. I have another engine I could use for the LT4 stuff that comes up of it once it comes back from the machine shop.

The factory LT1 pistons are pretty good for what they are. Thats why I was curious is there was an o/s offering for the LT1/ LT4. I could always put some hypers in it and call it a day...just seeing if there is an option from the general.

Are the LT4 pistons made by mahle? I seem to remember something years back about the LT1 pistons being made by them.

Supposedly the engine was out of a GS, but Im not too sure about that one. It was probably just a 96 M6 car, but who knows?

 

Uh huh... Please read full post.

 

Some of that would have helped besides saying it is a real LT4 in a 97 Camaro. That statement was misleading as you were already defending what motor was in it rather than saying you bought a 97 with an LT4 swapped in.

Don't know specifically on the pistons, but the LT4 isn't going to be anything special if you are replacing the overall rotating assembly. Run what you need/want for your build. The LT4 was just an LT1 with a few different (better) components. Once you start changing/modifying the components it's really going to be a built SBC with LT1 architecture. The aftermarket will probably provide better specialized solutions.

 

I did read your post and also the OP's original.

Maybe you need to better understand mine!! BLOCK CASTING is very different from VIN derivative. VIN derivative will ID it's originality, OP mentions GS and then just C4 LT4. VIN derivative would confirm which.

I don't have a problem with anything I posted.

 

Well, if I didnt say the engine was a real LT4 I would have had people on here trying to convince me I had an LT1 or something or another. Its an odd combination. I got it. I never said it was a factory SS LT4 car either. In any case, it doesnt matter... I think we are all on the same page.

Anyway, the plan was to reuse the crank (and perhaps rods if in good shape) with some new pistons in a 355 for something else after building a 383 out of the LT4. I know there are tons of options for pistons, I was just curious if there was a factory piston out there for repair jobs like some crate motors have before I went and looked at other options.

 

If VIN on block indicates a 97 model year it would be originally a blueprinted and reworked LT4.
As for building a stroker it depends on what you want to spend really. You could go with a thrifty 1500.00 kit or all forged 9k complete. Mahle, Wisco, JE are a few choices for pistons. You want to work with machine shop so block is bored to piston manufacturer's spec.s and finished for the ring manufacturer's spec.s. Discussing your goals is also an important of the process so there is no preventable disappointment..i.e. Incorrect part selection or non performed machining.

 

Yes Mahle makes an aftermarket Hyper piston that is similar to the factory LT4 with the addition of a skirt coating. The 4.030 bore size its quite difficult to get sometimes because all the oval track guys use them in "Stock" class builds because of the thinner metric ring package. They come complete with new pre-gapped moly rings.

Here are some in 4.040 bore size.

https://karlperformance.com/i-247123...3;brand:101285

https://www.ebay.com/itm/Mahle-22435...8/113635647762

Additionally Speed Pro makes an LTX replacement Hyper piston with the correct metric ring package. PN H597HCP. However they are expensive and so are the rings which are separate.

https://www.jegs.com/i/Sealed-Power/...97DCP/10002/-1

https://www.summitracing.com/ga/part...make/chevrolet

Will

 

It will not... he stated it is a 96, and more than likely that is a much more readily available source than a 97. Otherwise I would have real issues with his plan.

 

Sorry, I should have been more general in what I meant. The Block Numbers... as in the identifications numbers in general... but that is what I was getting at... if it was indeed a tied to a 97. It's not so it is water under the bridge.

 

Intial statement "got a 97 Camaro donating its LT4." 97 F Bodies with factory installed LT4 went to SLP where engines were reworked and blueprinted.

 

Silly question:

I see that stock LT1 pistons are made with Eutectic Aluminum/Silicon Alloy in my research. Is that considered an upgrade to a stock cast piston, but not as good as "forged" piston?

 

Better than just old cast pistons yes..... No where near as good as forged pistons. Hypereutectic pistons are still cast, they are just cast from an aluminum alloy that has a high amount of silicon in it. They are quite brittle.

Some people get away with a lot on them in boosted LS applications for a while. Some people find out why most engine builders refer to the (not so) jokingly as "Hyperexplosives".
Will

 

but will be OK with a modded N/A 475HP motor?

 

Could be fine, If it were me even the cheapest forged piston would be a good move.

Friends brand new 347 let go at 35 mph (hypers) there was nothing left of the engine that was useable, block, crank, cam in a few pieces, carb etc.Like a bomb went off.

 

I would and have used them in 350-400HP builds.... Nearly 500HP is forged piston territory IMO....

I tend not to push the limits of what amounts to stock replacement parts.... I don't like to see my stuff blow up and as has been said, when hypers let go it's usually total destruction.
Will

 

Sil-O-Vite has some stock replacement hypers in part numbers 1476HC and 3437HC (HC meaning hyper w/coated skirt).

Myself I think you should save yourself the cost of alignhone or alignbore and keep the LT4 assembly in the LT4 block then put the LT4 heads on the stroked LT1 block. That way you reuse the PM LT4 rods also.

Hope this helps.