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0trbo4myCHEVUICK 11-12-2012 09:18 AM

350///357 build
 
4 Attachment(s)
Hello! I have started numerous threads in the past and have always been helped. Im hoping to return the favor to someone like me, in the future. (Even though you can find this build type countless times on countless sites all the frick over the place)

Going to try and post the best pictures as well as price throughout the whole thing.

First step is buying different pistons for my 1986 STOCK rebuilt short block.
Then looking for a roller cam, spider, bones, etc roller train components.

Probably going to use H345CP spreed pro pistons. Im shooting for 9:1 compression. I dont have them yet but I have 400 set back for a set of 64cc vortec heads.

I spent 425$ on the short block and 50$ on a gasket set.

techinspector1 11-12-2012 09:58 AM

I don't understand why you would buy a completed short block and then want to begin changing parts, but hey, whatever.

Pay attention to the compression height of the pistons you plan to buy. Stock CH for a 350 Chevy is 1.560", but rebuilder pistons have a shorter CH (1.540") to compensate for shortening the deck height of the block. The shorter CH will make it more difficult to achieve a tight squish. Hang just the tip of one jaw of a dial caliper into the top of the pin bore and the other jaw at the crown just above the top ring. A 1.560" CH piston will measure 1.096"/1.097".

ap72 11-12-2012 10:35 AM

When you buy your pistons I'd buy a set that is close as you can get to the same weight as the ones you have, then balance them to match the pistons already in the block. It'll save you from having to rebalance it.

0trbo4myCHEVUICK 11-12-2012 11:02 AM

Quote:

Originally Posted by ap72 (Post 1610324)
When you buy your pistons I'd buy a set that is close as you can get to the same weight as the ones you have, then balance them to match the pistons already in the block. It'll save you from having to rebalance it.

Take both sets of pistons to machine shop and have them matched?

0trbo4myCHEVUICK 11-12-2012 11:07 AM

[QUOTE=techinspector1;1610307]I don't understand why you would buy a completed short block and then want to begin changing parts, but hey, whatever.

As this is my first build... I'm sure this wont be the first inefficient move I make.
I screwed up and jumped the gun on this deal. Now im hoping I will beable to install the new pistons myself? I assume I need to take the old piston/rod combo and have a shop switch the pistons?

Also I believe the H345CP speed pro hyper piston is a standard compression height piston.

ap72 11-12-2012 11:50 AM

[quote=0trbo4myCHEVUICK;1610332]
Quote:

Originally Posted by techinspector1 (Post 1610307)
I don't understand why you would buy a completed short block and then want to begin changing parts, but hey, whatever.

As this is my first build... I'm sure this wont be the first inefficient move I make.
I screwed up and jumped the gun on this deal. Now im hoping I will beable to install the new pistons myself? I assume I need to take the old piston/rod combo and have a shop switch the pistons?

Also I believe the H345CP speed pro hyper piston is a standard compression height piston.

they should be the correct height if they haven't changed anything.

As for weight matching you can do it yourself with a gram scale, or have a shop do it. you'll need to compare the specs before you buy though between your current piston and your next one- word of caution speedpro hyper pistons tend to be HEAVY. A set of very gently used stokc LT1 pistons may be better (they're hypers made by Mahle and lighter- but they have a metric ring pack).

0trbo4myCHEVUICK 11-12-2012 03:00 PM

[quote=ap72;1610343]
Quote:

Originally Posted by 0trbo4myCHEVUICK (Post 1610332)

they should be the correct height if they haven't changed anything.

As for weight matching you can do it yourself with a gram scale, or have a shop do it. you'll need to compare the specs before you buy though between your current piston and your next one- word of caution speedpro hyper pistons tend to be HEAVY. A set of very gently used stokc LT1 pistons may be better (they're hypers made by Mahle and lighter- but they have a metric ring pack).

So the LT1 pistons are a direct swap as any other piston? Is there a particular year of camaro? 1992 camaro pistons?

ap72 11-12-2012 03:37 PM

[quote=0trbo4myCHEVUICK;1610404]
Quote:

Originally Posted by ap72 (Post 1610343)

So the LT1 pistons are a direct swap as any other piston? Is there a particular year of camaro? 1992 camaro pistons?

any LT1 piston will work, you will need to get the correct rings though, and will have to check balance on everything again. You can try buying them from a yard but you can also watch local ads, craigslist, ebay, etc.

hcompton 11-12-2012 03:40 PM

From the pictues it looks like your block has new pistons in it. What is the purpose for the change? With 64 cc heads looks to me like your going to be close to 9.5 to 1 and use larger gasket if need be. Correct me if im wrong but arent the 4 valve flat pistons +5 cc right?

I would save the piston money and get aluminum heads. They will hold up and make good power. More importantly they are in the block and ready to go. Unless you want to run n2o i would leave them in place.

You can use a press to remove and install piston pins. They are cheap at harbor freight and always good to have around the shop. If not im sure at least one of your freinds has a press. If not machine shop should be very reasonable on this work.

0trbo4myCHEVUICK 11-12-2012 07:50 PM

[QUOTE=hcompton;1610421]From the pictues it looks like your block has new pistons in it. What is the purpose for the change? With 64 cc heads looks to me like your going to be close to 9.5 to 1 and use larger gasket if need be. Correct me if im wrong but arent the 4 valve flat pistons +5 cc right?


I wish those were 4valve relief flat tops but they are stock style dish...

bygddy 11-12-2012 09:18 PM

[quote=0trbo4myCHEVUICK;1610538]
Quote:

Originally Posted by hcompton (Post 1610421)
From the pictues it looks like your block has new pistons in it. What is the purpose for the change? With 64 cc heads looks to me like your going to be close to 9.5 to 1 and use larger gasket if need be. Correct me if im wrong but arent the 4 valve flat pistons +5 cc right?


I wish those were 4valve relief flat tops but they are stock style dish...

Yah, I have those same same...factory small dish piston...um.....am I missing a page here? I can spew the same stuff you have all heard about a solid fun budget combo...but will refrain till later.....your welcome.
What's the purpose? What's the budget? What's the platform?
Maybe I missed it somewhere?

0trbo4myCHEVUICK 11-13-2012 04:17 PM

The pistons have 423Np stamped on them. Probably a rebuilder piston. Like i said i jumped the gun on this deal and bought the thing before i did research on the pistons.

Looks like I would be lucky to have 8:1 compression with these pistons and probably wouldnt even have that.

I dont want to build a dog of an engine i want good quench and strong compression. I have been looking at H345CP speed pro hyper pistons, they state 9:25 compression with a 64cc head.

Now I am wondering about my rods, I know they have been "resized". Does that mean I should NOT be looking for a piston designed for a 5.7 rod?

I cant seem to find a weight spec on either one of these pistons and I know about balancing issues....

hcompton 11-13-2012 05:02 PM

Dont fix the block fix the part you do not have already. First off with 64 cc you will have more than 8:1 you should be able to buy heads in 58cc.

When i run my 350 numbers with 64 cc heads i get much diferent numbers.
United Engine & Machine Co. Incorporated

Check this site. Off the top of my head the stroke for 350 is 3.48 with gasket of 4.063 min and .043 thick with .025 deck and +5 cc dish i get 9.7:1 unless your dish is even more than 5 cc. You will need to actually measure i think once you run all the numbers you can rasie the compression with thin copper gaskets if need be but try to aovid it. Also gas is **** these days better to stay safe. 10:1 on iron heads is pushing it.

hcompton 11-13-2012 05:03 PM

Oh and still dont replace the pistons deck the block its cheaper than new pistons if you can take it apart your self and bring it to the machine shop bare. Hope this helps.

0trbo4myCHEVUICK 11-13-2012 05:09 PM

Quote:

Originally Posted by hcompton (Post 1610825)
Dont fix the block fix the part you do not have already. First off with 64 cc you will have more than 8:1 you should be able to buy heads in 58cc.

When i run my 350 numbers with 64 cc heads i get much diferent numbers.
United Engine & Machine Co. Incorporated

Check this site. Off the top of my head the stroke for 350 is 3.48 with gasket of 4.063 min and .043 thick with .025 deck and +5 cc dish i get 9.7:1 unless your dish is even more than 5 cc. You will need to actually measure i think once you run all the numbers you can rasie the compression with thin copper gaskets if need be but try to aovid it. Also gas is **** these days better to stay safe. 10:1 on iron heads is pushing it.



???? I am under the impression that the pistons in my short block are around -33cc maybe more becuse they sit lower in the hole "rebuilder piston"


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