L98 pistons vs compression ratio
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
or, maybe it was underrated so that the LT1 sales wouldn't drop...just like the 'underrated' lt4 argument v.s. the ls1...lol
:
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
I thought about that possibility after I posted, and think they would definitely at least use the exhaust manifolds/headers. I would still vote the bump in compression is more likely....but who knows what the general was doing for sure.
Mine originally had the "performance package" (supposed good muffler, 3.07 gear). The stock exhaust has been off the car so long now I don't remember if both outlets worked. I guess they probably did according to the other poster. To me it didn't matter, the car was a stone and thats why it needed some real changes. I do remember this was debated back when I first came on the board though..
Mine originally had the "performance package" (supposed good muffler, 3.07 gear). The stock exhaust has been off the car so long now I don't remember if both outlets worked. I guess they probably did according to the other poster. To me it didn't matter, the car was a stone and thats why it needed some real changes. I do remember this was debated back when I first came on the board though..
Racer
Joined: May 2008
Posts: 312
Likes: 19
I can say that my 91 one owner 83000 mi. all records ( I believe ) vette came with flat-top 4vr mahle cast on underside pistons. A stuck lifter and intake manifold coolant leak along with reseal and ring,bearing,bowl blend,clean,paint,ect., was the reason for the teardown. I can tell you the bores, crank, pistons, bearings, all looked and measured good and well within tolerance.
Melting Slicks
Joined: Aug 2003
Posts: 3,386
Likes: 390
From: Lakeville MI
88 piston info for reference:
I just pulled a cracked piston out of my 88. It has the following casting ID: 10046106.
The cracked one (#3), #4 and #7 also had broken skirts.
Part number is apparently 12361371
http://www.gmpartsdirect.com/perform...CATID=856.html
I just pulled a cracked piston out of my 88. It has the following casting ID: 10046106.
The cracked one (#3), #4 and #7 also had broken skirts.
Part number is apparently 12361371
http://www.gmpartsdirect.com/perform...CATID=856.html
Last edited by tequilaboy; Sep 11, 2011 at 12:10 AM.
Suckin' gas, haulin' ass.
Joined: Apr 2010
Posts: 1,100
Likes: 8
From: Newport News Virginia
I changed out the pistons in my '89 last fall. They were dished with 4 valve reliefs. I went with flat top Speed Pro pistons with 4 valve reliefs. My comp ratio should be around 10.5:1 with me decking the heads about 0.010".
Le Mans Master
Joined: May 2007
Posts: 8,448
Likes: 27
From: Valparaiso
Are those hypereutectics ? when i did my engine rebuild i bought Mahle Flat top .030Hypereutectic pistons now with AFR 195 65CC heads and Victor Reinz 5746 head gaskets
Compressed Thickness (in) 0.026 in. Compressed Volume (cc) 5.400cc im very curious about my current Compression Ratio !
i found a link :
http://malloryignition.racerswholesa...m?InvKey=62848
Compression ratio 64cc-10:1, 76cc-9:1
But not sure if its accurate
Compressed Thickness (in) 0.026 in. Compressed Volume (cc) 5.400cc im very curious about my current Compression Ratio !
i found a link :
http://malloryignition.racerswholesa...m?InvKey=62848
Compression ratio 64cc-10:1, 76cc-9:1
But not sure if its accurate
Last edited by Calderone; Aug 4, 2011 at 03:09 AM.
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
Are those hypereutectics ? when i did my engine rebuild i bought Mahle Flat top .030Hypereutectic pistons now with AFR 195 65CC heads and Victor Reinz 5746 head gaskets
Compressed Thickness (in) 0.026 in. Compressed Volume (cc) 5.400cc im very curious about my current Compression Ratio !
i found a link :
http://malloryignition.racerswholesa...m?InvKey=62848
Compression ratio 64cc-10:1, 76cc-9:1
But not sure if its accurate
Compressed Thickness (in) 0.026 in. Compressed Volume (cc) 5.400cc im very curious about my current Compression Ratio !
i found a link :
http://malloryignition.racerswholesa...m?InvKey=62848
Compression ratio 64cc-10:1, 76cc-9:1
But not sure if its accurate
Those are some strong pistons you have in '87 C4.
Hypertenutic is a good choice for street/ strip use.
Last a long time for You.
And you can do your own EFI tuning.
A big bonus for you also.
Brian
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Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
2:16 AM here now. LOL
You have to be around 9.5 to 10:1 with your AFR 195's.
The engine runs so strong for YOU.
You Peeling out for several hundred feet in the past showing us all the power on tap...............
It runs....
Not likely a 8.0 : 1 compression engine.
Goodnight Sammy
Brian
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
Less than a 1 month of Summer here Steve..........
Winter has to be closing in to an end there down under in Australia.
Have to be thinking alot about driving/making some fast 1/4 mile runs with your 1987 Black Vert & racing the "Heavy Metal Ford Cleveland Sedan too ............
Try & get on C4 again in a few hours to chat later Steve,
Need sleep here.
Brian
Winter has to be closing in to an end there down under in Australia.
Have to be thinking alot about driving/making some fast 1/4 mile runs with your 1987 Black Vert & racing the "Heavy Metal Ford Cleveland Sedan too ............
Try & get on C4 again in a few hours to chat later Steve,
Need sleep here.
Brian
Drifting
Joined: Nov 2009
Posts: 1,341
Likes: 2
From: Perth Western Australia
St. Jude Donor '10
Less than a 1 month of Summer here Steve..........
Winter has to be closing in to an end there down under in Australia.
Have to be thinking alot about driving/making some fast 1/4 mile runs with your 1987 Black Vert & racing the "Heavy Metal Ford Cleveland Sedan too ............
Try & get on C4 again in a few hours to chat later Steve,
Need sleep here.
Brian
Winter has to be closing in to an end there down under in Australia.
Have to be thinking alot about driving/making some fast 1/4 mile runs with your 1987 Black Vert & racing the "Heavy Metal Ford Cleveland Sedan too ............
Try & get on C4 again in a few hours to chat later Steve,
Need sleep here.
Brian
Drifting
Joined: Nov 2009
Posts: 1,341
Likes: 2
From: Perth Western Australia
St. Jude Donor '10
sv 727.8 cc (30 thou)
deck 5.5 cc
gasket 5.4 cc
chamb 65 cc
piston 3 cc
For my 87 with std pistons and 60cc milled afr195s and a thin gasket gives me 9.6 to 1.
Last edited by Lemme; Aug 4, 2011 at 06:40 AM.
Drifting
Joined: Nov 2009
Posts: 1,341
Likes: 2
From: Perth Western Australia
St. Jude Donor '10
Team Owner
Joined: Sep 2001
Posts: 62,119
Likes: 1,725
From: Athens AL
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