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Old 03-21-2006   #1
longtrackrmk
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Port Work On L82 Heads A Must Do!!!

First of all the head size is 72cc not 76cc on a 1989 5.7 GTA. Sorry for the mis information.
I am using the stock heads for my build, there was lots of room for improvement! I measured some of the ports and this is what I found!
(1) On the intake under the valve there is a huge lip that runs about 3/4 around just under the valve seat it measured 1.559" after removing it it measures 1.679" and is a smooth transitsion from the port to the valve. I dont see how they even flowed in stock form.
(2) on the exhaust side under the valve there is room to oped it up just under the seat to, it measured 1.194" and opened up to 1.253"
(3) On the intake runners there is a lip that runs down the inside edge about 1 1/2" in on one side, that measured 0.896 across the port before and 0.993 after. you could go more but the head is already thin there!
(4) then there was the gasket matching on the intake runners, the runners dont match the gaskets at all so there is another .200" you can remove there also, but it needs to be rounded to make a nice transition because the head is a little thin there to.
(5) On the intake side of the valve guide the leading edge can be shaved for a nice flow
(6) polish everything after all the die grinder work and your done.
only took about 14 Hr
all an all I think these heads can flow real nice with some work.
some say these heads dont flow, I can see why!, they will now!
After seeing how poorly they were stock I would not recommend putting on a aftermarket intake on like a STEALTH RAM without doing the head work, your not going to gain much!!!
Dont know if anyone cares, but this is what I found and thought I would post it.
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Old 03-21-2006   #2
twobirds
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Re: Port Work On L82 Heads A Must Do!!!

L82??? Thats a new one to me....Did you mean L98 or LB9?
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Old 03-21-2006   #3
longtrackrmk
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Re: Port Work On L82 Heads A Must Do!!!

Quote:
Originally Posted by twobirds
L82??? Thats a new one to me....Did you mean L98 or LB9?
I need to really get with it, yes L98 ! I have to many things going on it the little space I have left! I think its time for a drink, thanks for the quick response.
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Old 03-21-2006   #4
longtrackrmk
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Re: Port Work On L82 Heads A Must Do!!!

Quote:
Originally Posted by twobirds
L82??? Thats a new one to me....Did you mean L98 or LB9?
I suppose thats a good way to get people to take a look at this post.
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Old 03-21-2006   #5
ZZ4GTAMan
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Re: Port Work On L82 Heads A Must Do!!!

Great info Bro, thanks!

Mike
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Old 03-22-2006   #6
vejatabul
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Re: Port Work On L82 Heads A Must Do!!!

the l82 was a vette engine in the c3. not a great power house...
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Old 03-22-2006   #7
MunsonGTA
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GTA Year: 1987
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Re: Port Work On L82 Heads A Must Do!!!

weren't stock L98 heads 64cc? also, all that head work you did will help a modified motor, but not the stock LTR motor. It needs those smaller ports for velocity to help with the LTR setup, which is designed for torque. By adding more space you slowed down the velocity.

also, alot of people have put stealthrams on stock motors, and usually gain around 30-40 hp and only lose maybe 5-10 ft lbs of torque. A nice gain if you ask me.
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87 GTA: Forged 408 LSX short block, TEA stage 2 cnc ported 243 heads, BTR Stage 3 stroker cam, Fast 102 intake, NW 102 TB, Longtube headers, custom 411 ECM, custom harness, custom tuned, Performabuilt stage 2 4l60E with PTC 2800 stall, 9 bolt rear with 3.70 gears and TAP girdle.

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Old 03-22-2006   #8
longtrackrmk
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Re: Port Work On L82 Heads A Must Do!!!

Quote:
Originally Posted by MunsonGTA
weren't stock L98 heads 64cc? also, all that head work you did will help a modified motor, but not the stock LTR motor. It needs those smaller ports for velocity to help with the LTR setup, which is designed for torque. By adding more space you slowed down the velocity.

also, alot of people have put stealthrams on stock motors, and usually gain around 30-40 hp and only lose maybe 5-10 ft lbs of torque. A nice gain if you ask me.
I cc mine and they are 72cc. I think that removing the ridge from under the intake valve will help any engine setup . and for the motor build, I am going with a air gap intake, new hei, 4150 holley, trw 125 dome pistons, h-beam bushed rods, roller cam, roller rockers, true roller timing set, 3000 stall, bla bla bla, you know
Going back to a carb is more fun for draging / more options
I did not have the funds for a all out stroker build so this will have to do.
I see a couple of web sites that say the stealth only picked up 15HP on a stock motor. and one said the stock L98 only put out 225 HP
thats sad
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