Piston Questions

[1993blazerlt]

Do you think running theses http://store.summitracing.com/default.asp?target=esearch.asp&N=100&Ntk=PartSearch&Ntt=STL-H345NP&x=13&y=12
pistons i will need to get a custom chip? Also would it even be worth it to install these in the place of the stock pistons? What compression ratio would i be looking at with these pistons over the stock ones. The engine i am talking about is a 89 4.3 TBI

[bvr775]

Those are great pistons. well worth the money for a street truck and hold up pretty good to abuse.
I'll have to look at the specs for your engine, But i'm thincking your going to need rods too. what vin do have?
I don't thinck a comp reflash is going to be nessisary, but would be avisable.

[Matt 4.3 TBI]

I used SpeedPro part # L2256F20 (forged aluminum, .020 overbore) with my rebuild and it's at 9.6-1. Since those aren't overbore, the compression ratio will probably be close to stock (9.3-1) maybe slightly higher. I'm with bvr, your computer should be able to adjust to it without a problem, but you'll always get better performance out of a custom tune.

I'm not sure if the stock cast pistons were hyper's or not, but I doubt it. Those are definitely more durable than stock, and will hold up to more abuse. I didn't want to take chances, so I used forged :D
They should fit the stock rods without a problem, the ones I used did.

[DROPPEDGMC]

I'm with bvr, your computer should be able to adjust to it without a problem, but you'll always get better performance out of a custom tune.
i'd get one, get the most out of it


I didn't want to take chances, so I used forged :D
They should fit the stock rods without a problem, the ones I used did.
use arp bolts on the rods also. then spray the heck out of it:D

[biglouie_underpressure]

go forged! What are your plans for your truck? was it 96+ that had forged rods?

[biglouie_underpressure]

also.... i wouldn't buy a stock bore piston seeing your truck is a 93 ( how many miles?) i would bore it or have the bores checked to see if they are true.

[bvr775]

I looked at the specs on your engine and you shouldn't need a differnt size rod than stock, but you should still replase the rods. eagle, and manley make some good rods if your willing to pay the price.

[1993blazerlt]

the only reason that i was thinking about using these pistons is because they come with the rebuild kit and it is a really good price. The bores are fine they did not even have a ring ridge to be taken off. This is a cheap rebuild with a little more power in mind. The blazer this came out of had 126,000 but the shape this engine is in there is no way that it is the orignal engine.

[bvr775]

ohhh rebuild time!!!!

Is it a complete rotating assemble(cranck,rods,and pistons) or just pistons?

[1993blazerlt]

the kit comes with just the pistons it is more like a engine refresh because the crank journals are still in great shape. The engine sat a long time so i figured i might as well freshen it up and port the heads also while i have it a part

[biglouie_underpressure]

[the only reason that i was thinking about using these pistons is because they come with the rebuild kit and it is a really good price. The bores are fine they did not even have a ring ridge to be taken off. This is a cheap rebuild with a little more power in mind. The blazer this came out of had 126,000 but the shape this engine is in there is no way that it is the orignal engine.
__________________QUOTE] not trying to be an @ss but you can't look at a bore and tell it's true.Sure you can use a refresh but will it hurt you ? if your going that way why don't you just get some rings and bearings.
__________________

[1993blazerlt]

yea but with the kit that summit sells it works out to be only like 30 dollars more to get the pistions which is not a bad deal at all. I do have a dial bore gague so i was not just looking and guessing at the condtion of the bores

[biglouie_underpressure]

kool!!Looks like your know what your doing. I'm stll learning one day i'll build a motor.