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Old 11-20-2018, 05:40 PM
madden madden is offline
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Default 1970 lt1 deuce pistons

hi

can some one tell me if the the original pistons for my deuce should be LT1 350 "std" or .030 over pistons.........and they should be press fit correct?

also are the 69 302 pistons the same .030 over dia pistons except they are floating pin?

thank you so much

regards
chris
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Old 11-20-2018, 05:54 PM
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Original "LT-1" pistons for your Deuce would be standard size with press fit pins. 69 Z-28 pistons had floating pins. I think the pin height of the 350 pistons versus 302 pistons is different as well in addition to the press pin versus floating pin. Pin heights vary due to crankshaft stroke being different on the two engines.

I'm sure one of the engine gurus will chime in, but that's what I recall.

Last edited by COPO; 11-20-2018 at 06:04 PM.
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Old 11-20-2018, 06:00 PM
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To the best of my knowledge the LT1 was a standard bore 11:1 high dome piston....these pics are from my 70 Z28 engine rebuild. Note part number stamped on the top of each piston...
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Old 11-20-2018, 06:04 PM
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LT1 pistons and 302 pistons look similar, but as noted, because they use the same length rod, the pin height is different.

The dome on the 302 is slightly higher, but barely noticeable.

69 L46 used the same piston as the 70 LT1. Both are press fit as noted, although the pistons have provisions for spirolox, so would be easy to convert to floating. No performance gain.
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Old 11-20-2018, 06:40 PM
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Wiseco Pistons will work fine and pink rods are really not necessary.
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Old 11-20-2018, 08:10 PM
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so that i am clear

for my LT1 deuce

1) the pins will be press

2) the pistons have to be for LT1 sbc NOT 302 sbc

3) pistons i need are GM#3959456 or GM TRW L2304 replacement?

i also read here on the site that they should be .030 over??
is this correct or not??
should they be 4.000 dia OR 4.030 dia?

im reading different things?

thanks so much
regards
chris
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Old 11-20-2018, 09:30 PM
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The LT1 came from the factory with a 4.000 inch bore. If the block has not been bored oversize then you need pistons for a 4.000 inch bore. If the block has been bored oversize then you need to know how much it has been bored and get pistons to fit your bore size. If your block is worn and needs to be bored then you will need to talk with your machinest and figure out how much it needs to be bored and get pistons to fit after it has been bored.
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Old 11-21-2018, 12:38 AM
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i understand boring a block as i have several drag cars that i built engines for

my issue was i did not know if the LT1 came with 4.00 inch bore OR 4.030 bore due to the fact i had read some many different things on this site and others

i felt that it could have been very possible for don yenko to bore the yenko engines out for several reasons

thanks everyone for the answers

i will continue looking now for LT1 4.00" OD forged GM TRW pistons

thanks again
regards
chris
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Old 11-21-2018, 01:01 PM
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Quote:
Originally Posted by 70 Forest Green Zee View Post
To the best of my knowledge the LT1 was a standard bore 11:1 high dome piston....these pics are from my 70 Z28 engine rebuild. Note part number stamped on the top of each piston...
FYI All of your pistons are in backwards. Im guessing including the Thrust side of the rods...
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Old 11-21-2018, 01:34 PM
madden madden is offline
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hi

kenmaisano post comment

this is not my deuces engine pictured here.......picture was posted by another site member to show piston part numbers

thx
chris
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