Nope.

396ci is about 13% larger than a stock 350. Advantages are more torque and lower in the rpm band. The cost of a new 3.875" crank compared to a stock stroke of 3.48" of similar quality is negligible. If you are buying new pistons anyhow, why not increase the stroke? I think the 3.75 is a better bet though. 396 requires more block clearancing and pushes the pin up pretty good in the piston w/ a 6" rod. 383 is nice compromise of increased ci, decent rod/stroke ratio, and piston strength.

0.005" is nothing but a basic clean up. Will not affect anything.

How much do you want to spend What is your HP goal? You have options - if your motor checks out and only needs a touch hone, new rings and bearings, then weigh that against the cost/benefit of an assembled shortblock. Personally, I would get rid of those pistons regardless of condition, Get some SRP or other dished piston, ARP rod bolts & main studs, new bearings. Then have at it.


EDIT: Oh, and fix the blower (or go turbo). You felt what, 8psi? Imagine zero...yuck.
EDIT2: What model Vortech and what are they quoting to rebuild? (don't rebuild it yourself)
-Scott

 

I thnk we are staying with our 355 block

We are trying to keep this as budget as possible. I just want to fix this and enjoy the car

Why would you get rid of the Pistons? I will be putting everything through a parts washer.

We are sending a V1 to be fixed.

 

If your pistons are ok you could run them again, but they're 10.5:1, aren't they?

I personally would put a forged dished in there to drop the compression ratio to allow you some room to tune and/or run some real boost on it with pump gas.

If you want to proceed, 10.5 static on pump will be your limiting factor, not a maxed V1 S-trim.

My 2 cents,
-Scott.

 

Thank you

My pistons say : 5028H3 I will look for a photo. -says it is a flat top with 4 reliefs.

I think those are flat top pistons ?

i dont plan on ever running up the boost as i have 2 bolt mains on the car.

 

Brad,

Understood. But a lower compression ratio will allow you to take the combo further. Now would be the time to do it, especially if the pistons have any damage due to eating the compressor.

I understand wanting to run what you have - A budget's a budget - but then again so was rebuilding your own blower.....right?

A lot of guys here thought you cracked a ring land due to detonation. If you put a 10.5 piston back in there and dont get the fueling right, you could end up re-living this experience. A set of dished SRP's can't be more than $450 or so - and then you can throw all an S-trim has to offer at it.

-Scott.

 

Is the S-Trim the V2 SQ..

I am taking what you say very seriously and will think about the dished pistons.

With a V2 SQ - running 8psi - will my 30# SVO ford motorsport injectors be sufficient - and my CC 305 cam.

for ring gap we were told .004 for the top and .005 for the bottom running 8psi - about 500 hp.

Any other things to consider at this stage - thank you once again!

Thank you.

 

Huh? Who told you that? The only way i could understand that is those numbers added to stock numbers. Like .024/.025 at least. You definitly want them larger then a stock ring/piston setup. Suggested ring gaps usually come with the pistons if i remember right. NA setups all the way up to severe boost/nitrous race setups. You should think about a softer forged aluminum piston due to it's somewhat more forgiving nature with detonation. The harder aluminum will crack easier (not as forgiving). You'll probably need more fuel at 8psi, but you haven't shared your fuel setup. My guess is at least a 255hv intank pump with probably 36#ers. Have you even pulled the pistons out of the block yet? Like boosted said, you should do a little planning ahead, even if you currently think you won't take your setup any further. You'll thank yourself later...

Ken R.

 

Thank you for the reply again.

Yep - 255 in tank with 30# SVO's
the ring gap numbers came from the tech at wiseco pistons when told it was not a racecar and that the car would be supercharged to about 500hp. He said at that hp they wouldent heat up thatt much. He left one ring smaller than the other for fluid drain. Let me know what gaps you feel i should be using. and what kind of pistons should i be using i thought i had forged aluminum. Pistons are still in the block - we should be pulling the block this weekend.

Thanks.

 

Brad,

A ring gap of 0.004 or 0.005" make no sense. What I think the Wiseco guy was probably trying to tell you is for a street engine, you can use 0.004" gap for every inch of bore diameter. Example: 0.004 X 4.030" = 0.016" gap. That may work nice in a stock rebuild but is way too tight for anything with boost. DON'T DO IT. I highly encourage you to find a local engine builder or spend some time learning about engines if you are attempting this yourself.

Look at the chart on the first page of this link.

http://www.cppistons.com/LinkClick.a...j8%3D&tabid=75

If you need some reading on engines, go over to Amazon and pick this one as your first:

http://www.amazon.com/Rebuild-Small-Block-Chevy-Engines-Hp1393/dp/1557883939/ref=sr_1_5?ie=UTF8&s=books&qid=1239828797&sr=8-5

Regards,
Scott.

 

Yes he was saying.004 x 4.030.
I have that book at home bought it a while ago.

I will talk to a local engine builder - what gap would you run for my application?

 

Hopefully others chime in, but if it were me, i probably wouldn't run anything tighter then say .023/.025 in that setup. Should probably go a little bigger, again, for future use for one thing. Also, going bigger may lose you a few HP, but the safety factor i think overweighs that. As for the pistons, i'm sure your forged, but there are different material types used in forged pistons. I forgot what the material number was between types, but lets take a -31cc JE forged blower piston (the type i'm currently using) vs. a -31cc SRP forged piston. Technically there made by the same company, but two different materials. The JE is more forgiving, but at the expense of more weight. Some have had success with the SRP's, but many have had bad luck. I believe there is a long post about them if you search it.

Ken R.

 

I always would rather sit on the side of caution... .025 / .027 perhaps.
What would me converting to blower (dished) pistons do..I know it would be more forgiving and lower my compression ratio - why is that important? I know the LT1 runs high compression stock. Will that allow me to tweak more things with my computer emulator? Or is it safer for the car?
Needless to say I don't want to do this all again anytime soon out of necessity.

Thank you for offering a number for the gaps - i will check with the guy that did my heads and cleaned the engine cleanup for his take on the pistons / gaps. Unfortunately the engine builder i am going to is very conservative with 2 bolt mains and LT1's in general. He finds them to be a weak engine - the gentleman has been doing engines for many many years and does not have faith in the motor - I have great respect for him though

 

Found a hole in piston number one... heres the deal

Option one - have engine builder mic everything up, and boil it out I try to clean everything and hope i get ALL the metal out of the engine / parts. So this doesn't happen again.. That will cost at a MINIMUM of 1200 - just replacing 2 pistons.

Option 2- buy a new shortblock maybe a 383 / 396 for 3800 from olen or VRE ( OR any other vendor you know of) - and know nothing is wrong with them.

What do you think?

 

What exactly is he doing for $1200?

Option 3 - Find someone else to talk to?

 

1200 was for boil (150) / ball hone / mic all (total labor 400) / then the cost of all bearings (100) / 2 pistons 160 ( would like to replace all) / rings 100 / and gasket set for us to assemble 200