View Full Version : Stock Pistons or not?


Powers76
04-17-2009, 02:53:03 PM
I just took the heads off my 350 and wasnt sure if these are stock pistons or not. I tried searching online but all i could find for stock 350 pistons were flat tops with 4 valve reliefs so for anyone that has tore apart a 350 do these look stock?

http://i42.tinypic.com/2cxcn6t.jpg

K5JMP
04-17-2009, 03:24:41 PM
if it was a late 60's thru about 73 original build.. mebbe.. but I doubt it.
has been a long time since pop-ups (domed pistons) were a factory item.

look for a number on the top of the piston... will be tough to see as the carbon may have filled it in.

I will say it looks waaaay loose in the bore:eek:

sooner
04-17-2009, 03:25:13 PM
Look like .100 domes to me.

Powers76
04-17-2009, 03:28:13 PM
i actually was able to get the numbers and it said 7002P on the bottom part of the piston and 030 on the top so what does that indicate?

K5JMP
04-17-2009, 03:33:34 PM
i actually was able to get the numbers and it said 7002P on the bottom part of the piston and 030 on the top so what does that indicate?

.030 overbore.. and found this with google...
pdq67
03-05-2006, 11:44:04 AM
I found Speed-Pro's 7002P and 7502P factory 327, 11 to 1 CR. pistons.

Book doesn't list their spec's! Say's, "Forged Duplicate of Factory Piston"..

A 7046P 283 FI piston at 11.6 to 1 CR. is 19.3 cc in standard bore.

The only problem here is that these pistons appear to be the later designed domes and not the older half round ones??

I probably have this info. somewhere in my stash of old mag's and cat's, but where??

Sorry,

pdq67

http://www.nastyz28.com/forum/archive/index.php/t-43908.html

Powers76
04-17-2009, 03:42:29 PM
.030 overbore.. and found this with google...

http://www.nastyz28.com/forum/archive/index.php/t-43908.html

what does .030 overbore mean and it says 11 to 1 compression with 19cc chamber but what about my 64 cc chamber? are these good piston?

warped
04-17-2009, 04:01:45 PM
A 0.030 overbore means that the cylinders were scored or perhaps out of round at some time in the past. To remedy this, the original bore (4.000) was increased by 0.030. This requires a larger diameter piston and if the stroke remains the same, the engine displacement is now 355. Good luck.

Powers76
04-17-2009, 04:07:53 PM
well this engine is just full of surprises. so the domed pistons were probably put in to keep the compression ratio close tithe same right?

K5JMP
04-17-2009, 04:08:27 PM
what does .030 overbore mean and it says 11 to 1 compression with 19cc chamber but what about my 64 cc chamber? are these good piston?

speed-pro's are as good as any... and better than a lot of them;)

warped
04-17-2009, 05:08:55 PM
Are you sure the engine was originally a 350? It almost sounds as though it is a mid 60's era 327. Post up some casting numbers and dates and we can determine the origin of the engine.

hhott71
04-17-2009, 07:17:38 PM
Use a ruler. If the piston at bottom dead center is 3 1/2" deep its a 350
3" deep its a 302, 3 1/4" deep its a 327.

Powers76
04-19-2009, 03:41:03 AM
Use a ruler. If the piston at bottom dead center is 3 1/2" deep its a 350
3" deep its a 302, 3 1/4" deep its a 327.

can i just measure the bore and see if its 4.03" cuz thats what a 350 is right

hogg
04-19-2009, 04:31:36 AM
4.0" bore for 350 or 327or a 302 cu.in. hhott71 was saying how for the piston will go down in the hole,from start, when the crank is turned.3 1/2"=350,,,3"=302,,3 1/4"=327 you said yours was .030 over bore ,=yours some where at 4.030 across bore=

tom3
04-19-2009, 12:43:05 PM
Might be the old forged TRW popups for the 327. TRW 7002p-0.30 I think I see chamfers on the tops of the bores too. Might have been a somewhat serious race engine at one time? Looks like some major piston to bore clearance now though.

pdq67
04-19-2009, 05:07:01 PM
Suckers appear to me to be DITH piston of an 1/8" just looking?????

Maybe, somebody has tried to hold the CR using them and not correct cc chamber heads??

pdq67

Powers76
04-19-2009, 07:02:40 PM
Suckers appear to me to be DITH piston of an 1/8" just looking?????

Maybe, somebody has tried to hold the CR using them and not correct cc chamber heads??

pdq67

DITH?

RacerRick
04-20-2009, 12:41:46 PM
DITH?

I think he means "dish" - he's just typing with a lisp.

Powers76
04-20-2009, 12:56:08 PM
I think he means "dish" - he's just typing with a lisp.

lol well either way it appears i have found one more thing I got lied to about because the piston only goes down 3 1/4"

K5JMP
04-20-2009, 01:02:25 PM
lol well either way it appears i have found one more thing I got lied to about because the piston only goes down 3 1/4"

that would indicate a .030 over 327ci motor.

Powers76
04-20-2009, 01:33:02 PM
that would indicate a .030 over 327ci motor.
ya I wasn't too happy to find that but if the only difference is the crank can I get the crank from my 76 350 and put it in there? or would I have clearance issues

74RAT
04-20-2009, 07:28:45 PM
pdq is saying DITH,, meaning "down in the hole".
he's really asking if they actually come all the way to the top of the deck when you roll it to tdc for a given piston??

he's thinking maybe a wrong piston application to the crank,, like 327 pistons on a 302 crank or something crazy like that. hope it helps.
andy

KansasTwister
04-20-2009, 08:10:33 PM
depends, if you have a small journal 327 the 350 crank wont work, but if its large journal 350 crank will work, most 68-69 327 cranks werent forged, but all small journals were. granted your 76 crank may or may not be forged depending on its orignal vehicle it was installed in.

Damon
04-20-2009, 10:42:05 PM
Run the casting number off the block through Mortec.com

If it's a 68-up block it's large journal (350 crank will drop in), if it's 67 or earlier it's small journal.

And if it happens to be small journal, DON'T build it- SELL IT! Not becuase there's anything wrong with it, but you're likely to get enough money for it to buy a complete 350/383!

Powers76
04-21-2009, 03:02:48 AM
depends, if you have a small journal 327 the 350 crank wont work, but if its large journal 350 crank will work, most 68-69 327 cranks werent forged, but all small journals were. granted your 76 crank may or may not be forged depending on its orignal vehicle it was installed in.

my 76 350 came out my 76 camaro lol

Powers76
04-21-2009, 03:09:26 AM
Run the casting number off the block through Mortec.com

If it's a 68-up block it's large journal (350 crank will drop in), if it's 67 or earlier it's small journal.

And if it happens to be small journal, DON'T build it- SELL IT! Not becuase there's anything wrong with it, but you're likely to get enough money for it to buy a complete 350/383!

casting number on the block is 3970010 which says its a 69-305, 327, or a 69-80-350. one quick question i have though is it possible that maybe it has different longer rods or something that could make it so it only goes down 3 1/4" instead of 3.5"

Powers76
04-21-2009, 03:28:52 AM
The 010 block was used on 302, 327 or 350. Always a 4in bore. Always large (2.10) journal. The stroke varied 3.00, 3.25, or 3.48. It is very possible that a 3.25 stroke 327 crank was used with 350 pistons. If so the pistons would be 1/8th down in the hole. But I must say that those pistons don't look like 350 pistons. They look like something from the sixties. Maybe the piston was not at full stroke?
whats the difference between 327 pistons and 350 pistons? and im not sure if that picture was taking at tdc what does it mean if at tdc it was 1/8th of an inch down

Powers76
04-21-2009, 07:04:28 AM
The difference (+-1/8th in) is the distance from the connecting rod pin to the top of the piston. If you turn the crank, the top of the pistons (not the dome) should be nearly even the top of the block. If it's 1/8th in down you probably have a 327 crank with a 350 piston. The motor will not run properly (if at all) like like this. The compression will be very low.
if the piston is all the way up to the top of the block wouldnt it be really close to hitting things?

RacerRick
04-21-2009, 10:59:46 AM
From the information you have given, you have a large journal 327, and the pistons were identified as 327 pistons for a block that hase been overbored 0.030".

If you want a 350, you just need to change the pistons and the crank.

Powers76
04-21-2009, 01:55:04 PM
From the information you have given, you have a large journal 327, and the pistons were identified as 327 pistons for a block that hase been overbored 0.030".

If you want a 350, you just need to change the pistons and the crank.
Deal i already have the crank from my old 350 :cool: i know i wont be able to compare what the engine used to be like since im rebuilding it now but would there have been a noticeable power difference if i had made it a 350 and kept everything else the same?

Powers76
04-21-2009, 06:11:06 PM
I checked to see if the piston went up in the bore all the way and it does, there is however some carbon buildup about a quarter inch down the cylinder. After a close look the piston doesnt look like it its loose in the cylinder like it does in the picture so were fine there but if i put my 350 crank in will i need new pistons or can i get shorter rods because since the block is bored 030 over its either new pistons or new something else because my other 350 pistons wouldnt fit i dont think

http://i41.tinypic.com/2wfu8up.jpg

sooner
04-21-2009, 06:24:41 PM
Can you post a pic of your harmonic balancer? If its factory and its a skinny 6" balancer it should be a 327. Someone please correct me if im wrong.

Powers76
04-21-2009, 08:36:18 PM
Can you post a pic of your harmonic balancer? If its factory and its a skinny 6" balancer it should be a 327. Someone please correct me if im wrong.
ill try and get a pic im not at home but it is pretty skinny so it might be

1970camaroRS
04-22-2009, 05:06:56 AM
I wouldn't worry too much about making it a 350. I bet there's a chance that the 327 crank you have is forged. I'd take it all apart, make sure the holes are still 4.030, re-ring everything, add good heads, a large cam and call it good.

RacerRick
04-22-2009, 11:56:09 AM
All but a very few large journal 327s were cast. 327 large journal crank that are forged are very rare.

Why not just run the 327 - they are a good motor and like to Rev.

Powers76
04-22-2009, 06:22:52 PM
All but a very few large journal 327s were cast. 327 large journal crank that are forged are very rare.

Why not just run the 327 - they are a good motor and like to Rev.
idk the 350 just sounds more appealing lol its bigger and i already have the crank from my old one

WildBillyT
04-22-2009, 06:35:43 PM
Not trying to be a jerk, but are you sure you are getting an accurate measurement of the stroke? If you are going to be pulling the oil pan anyway why not do that and get the numbers off of the crank?

Powers76
04-23-2009, 02:46:44 AM
Not trying to be a jerk, but are you sure you are getting an accurate measurement of the stroke? If you are going to be pulling the oil pan anyway why not do that and get the numbers off of the crank?
ill do that just to make sure but im pretty sure i got the correct reading, i put the piston at BDC and measured to the lowest part of the piston( not the dome) and it was 3 1/4 inches down but where do i get the crank casting number when i get to it

pdq67
04-23-2009, 10:24:04 PM
If it is 3.25" dith, (down in the hole piston), then it is a 327, no matter of the crankshaft main bearing diameter!

It looks to me to be a 350 engine w/ a non-stock, domed, 327 piston in it.

And if you really want to know what you have, then post back the letters that should be at the end of the long VIN number string that again should be on the little deck pad above the pass. side, top water pump bolt and we will tell you what it is IF it is still a virgin.

Probably not, but we will know the stock block B&S!!

pdq67

Powers76
04-24-2009, 03:04:57 AM
If it is 3.25" dith, (down in the hole piston), then it is a 327, no matter of the crankshaft main bearing diameter!

It looks to me to be a 350 engine w/ a non-stock, domed, 327 piston in it.

And if you really want to know what you have, then post back the letters that should be at the end of the long VIN number string that again should be on the little deck pad above the pass. side, top water pump bolt and we will tell you what it is IF it is still a virgin.
Probably not, but we will know the stock block B&S!!

pdq67
wait... so your saying it could be a 350 with 327 pistons in it... does that make it a 350 or not lol and i got the number and its V1011TRG. I tried searching online but havent picked up anything for it

Edit: I just found info "TRG= year:1972 CID:350 application:van & bus hp:175 body comments:C-30"

so im a little confused. does this mean it is a 350 or isnt?

RacerRick
04-24-2009, 02:58:01 PM
That motor has obviously been rebuilt since its bored 0.030" over already, and has a 3.25" stroke crank in it. Both the 350 and 327 share the same bore size, so just be putting the longer 3.48" stroke 350 crank in the motor you will end up with a 350.

Its not stock and you are planning on rebuilding it as a 350 so all that really matters is how good of shape the block is in.

pdq67
04-24-2009, 04:17:07 PM
Measure it and see if it's B&S is a 327 OR a 350 so you will know for sure is all I'm saying.

pdq67

hogg
05-06-2009, 11:18:41 AM
you'll still need .030 new pistons,for 350+, i would rather have the domed 327,,o30 over,64cc heads and check out the cam,crank and block buy machine shope. may all be good,can't see a person building a domed piston 327 ,with out a wild cam.

MadMike
05-06-2009, 11:48:28 AM
idk the 350 just sounds more appealing lol its bigger and i already have the crank from my old one

???????????????

Build this thing... I've been following along with your other thread (build a 350 or not...) and this engine is sounding like something you may enjoy. Have you ever heard THIS engine run?

Use this stuff... 11.0:1? You want a 350 cause it sounds better? Let the ENGINE do the talking (popping & snapping). Screw with people and tell 'em it's a 305... who cares..... you know it's a 327 and anyone who hears (and smells) the thing will be scratching their head.

Powers76
05-06-2009, 01:59:05 PM
???????????????

Build this thing... I've been following along with your other thread (build a 350 or not...) and this engine is sounding like something you may enjoy. Have you ever heard THIS engine run?

Use this stuff... 11.0:1? You want a 350 cause it sounds better? Let the ENGINE do the talking (popping & snapping). Screw with people and tell 'em it's a 305... who cares..... you know it's a 327 and anyone who hears (and smells) the thing will be scratching their head.

ha ya I think I was just disappointed at learning it was a smaller engine and that I was lied to but I have decided to build the 327o I actually think I will like it more like this. I liked it when I thought it was a 350 so why change it ;-)