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street/MILD motor build

I love my Chevy Chevette!
Posts: 1
Joined: 02/13
Posted: 02/20/13 08:46 AM

ok, so not new to engines, rebuilds, etc.  but the current build, i'm trying to dial everything in with what i have correctly.  this is a street/cruiser build, it will see OCCASSIONAL track time, but i have no illusions of blistering speed.  just something fun to drive.  and simply race once in awhile.  not an all out beast.

the setup:

.030 over 350, flat top 4 valve relief, stock rods, crank.  comp cam xe262  218/224 @ .050, 462/469 lift, 110 lsa, 106 centerline.  93 '810 tbi truck heads(YEA I KNOW!!!!  but this is a cruiser mind you) besides, i got a great deal.  was going vortec route,long story but got burned BAD, so vortec is out.  so no "go vortec" please. not gonna happen.  edelbrock 2104 intake, 1 5/8 headers thru 2 1/2 exhaust.  no cats.  cliff ruggles built/tuned qjet carb,  standard HEI with 65k coil, pertronix ign module, taylor spiro pro 8mm wires.  

car is:  90 camaro, 700r4, stock trans and conv.  3.23 rear gears.  

question has to do with motor.  the heads are 1.94 valve 65cc.  my pistons are .012" below deck.  according to reputable calculators, using a 4.125 bore, .039 head gasket, i'll end up at about 9.9:1 compression, BUT with a .051 quench/squish.  this is where opinions GREATLY differ.  motor will obviously be a bit torqy, with rpm's around 2k-3k.  so, should i use a thinner gasket, which will up compression to 10.25:1 but give me a .042 quench, or am i worried for no reason?  

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I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 02/20/13 03:23 PM

Nothing wrong with a street car and an occasional trip down the track. I did that with many of my early cars.
I would not worry about the small compression increase gained by the thinner gasket. I ran some pretty thick copper gaskets, copper is reuseable, on my race motors but they never blew out under nitrous use.  

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I love my Chevy Chevette!
Posts: 12
Joined: 02/13
Posted: 02/21/13 06:59 PM

Dave, Ran a Pro Mod Beretta so he knows about head gaskets that seal. When you run 4 stages of juice! Ask Dave...
  You have to build an engine to make a trip to the 1/8th or 1/4 mile.The Cam you have is respectable, just make sure the valve springs are correct for the cam. The old Z28 valve spring is a great spring to .500 lift. What most guys forget is the rear gear ratio, if you had 3:70 or 3:90 Rear gear that would wake your Camaro up. With the 700R4 trans. the OD will bring you to around 2,400RPM at cruise speed 70MPH with a 26" tall tire.
  You have the small 7.5 ring gear. I think that series housing is okay to put a lower gear in it without changing the center section.
  Yes quench is a concern. If you had a 17:5:1 compression ratio engine you would be very concerned about quench. But don't let it beat you up. You know what you need to be concerned about.
  I would use a forged piston, with a moly 1st ring, moly 2nd ring. Use the .004 per 1" of bore. So .018-.020 top ring and the same on your second ring. (Or whatever the ring maker suggests).
   Main and rod bearing clearances use the stock clearances. Don't try anything trick for the street.
  Use a stock Chevy Z28 pump. It's all I've used in my small blocks. They were all blue printed.
  Make sure there are NO SHARP edges on any of the valve reliefs,piston edges, even the engine block. Don't be affraid to take a fine 1/2 round file to the top of the block. (DON'T LEAVE ANY BURRS) When everything is nice and smooth on the dome of that piston. (Sharp edges make hot spots) (Hot spots cause PING and/or Detonation). Even the combustion chamber of the cylinder head. Get everything in there as smooth as a babies butt. Even run that fine file across the top of the block.

Bob Aka-pepsi1  

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V-6 Camaros rule!
Posts: 46
Joined: 07/13
Posted: 07/10/13 12:17 AM

Yes, go with a thinner head gasket, anything greater than .045 will put you in danger of detonation and could destroy all your hard work.  

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