I have an 88 Formula 350 and I was looking into a cam, but one of my friends said that the Formula's had iron heads instead of aluminum. He said the aluminum Corvette heads only came on the Trans Am 350's? If you can help it would be much appreciated.
Banned
Aluminum Corvette heads only cam on the COrvettes. THe L98 in any F-body had Iron heads.
I think not 100% sure maybew someone else can back me up here, but I see a lot of people going after the L98 ALuminum heads
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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555
Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!
I think not 100% sure maybew someone else can back me up here, but I see a lot of people going after the L98 ALuminum heads
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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555
Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!
TGO Supporter
What Kyle said. No stock 3rd Gen F-body came with aluminum heads. And yes, swapping to aluminum L98 heads is a popular modification.
It is extremely popular with 305s as the Aluminum L98 heads valve size offers a performance increase over the smaller 305 valve size, yet still clears the bores. Also, the Aluminum L98 heads have the same 58cc combustion chambers as the iron 305 heads, so there is no compression loss.
The Aluminum L98 heads are also popular on the 350s but for slightly different reasons. The smaller combustion chamber (58cc vs 64cc Iron head) gives a compression increase that compensates for the thermodynamic losses of aluminum. Also, the Aluminum L98 heads can be ported to flow extremely well and larger valves can be added.
The last, but not least reason, for swapping to aluminum heads is weight savings.
There are disadvantages with aluminum, like lower thermodynamics efficienies (as mentioned earlier) and it is far easier to strip a bolt or cross-thread a spark plug. Iron heads tend to be more durable and less susceptible to warping making them more desireable for long term use.
It is extremely popular with 305s as the Aluminum L98 heads valve size offers a performance increase over the smaller 305 valve size, yet still clears the bores. Also, the Aluminum L98 heads have the same 58cc combustion chambers as the iron 305 heads, so there is no compression loss.
The Aluminum L98 heads are also popular on the 350s but for slightly different reasons. The smaller combustion chamber (58cc vs 64cc Iron head) gives a compression increase that compensates for the thermodynamic losses of aluminum. Also, the Aluminum L98 heads can be ported to flow extremely well and larger valves can be added.
The last, but not least reason, for swapping to aluminum heads is weight savings.
There are disadvantages with aluminum, like lower thermodynamics efficienies (as mentioned earlier) and it is far easier to strip a bolt or cross-thread a spark plug. Iron heads tend to be more durable and less susceptible to warping making them more desireable for long term use.
Member
Quote:
<font face="Verdana, Arial" size="2">Originally posted by Glenn91L98GTA:
What Kyle said. No stock 3rd Gen F-body came with aluminum heads. And yes, swapping to aluminum L98 heads is a popular modification.
It is extremely popular with 305s as the Aluminum L98 heads valve size offers a performance increase over the smaller 305 valve size, yet still clears the bores. Also, the Aluminum L98 heads have the same 58cc combustion chambers as the iron 305 heads, so there is no compression loss.
The Aluminum L98 heads are also popular on the 350s but for slightly different reasons. The smaller combustion chamber (58cc vs 64cc Iron head) gives a compression increase that compensates for the thermodynamic losses of aluminum. Also, the Aluminum L98 heads can be ported to flow extremely well and larger valves can be added.
The last, but not least reason, for swapping to aluminum heads is weight savings.
There are disadvantages with aluminum, like lower thermodynamics efficienies (as mentioned earlier) and it is far easier to strip a bolt or cross-thread a spark plug. Iron heads tend to be more durable and less susceptible to warping making them more desireable for long term use.</font>
Where's the best place to find aluminum L98 heads? Do most people get new castings from the dealership, or is that too expensive?<font face="Verdana, Arial" size="2">Originally posted by Glenn91L98GTA:
What Kyle said. No stock 3rd Gen F-body came with aluminum heads. And yes, swapping to aluminum L98 heads is a popular modification.
It is extremely popular with 305s as the Aluminum L98 heads valve size offers a performance increase over the smaller 305 valve size, yet still clears the bores. Also, the Aluminum L98 heads have the same 58cc combustion chambers as the iron 305 heads, so there is no compression loss.
The Aluminum L98 heads are also popular on the 350s but for slightly different reasons. The smaller combustion chamber (58cc vs 64cc Iron head) gives a compression increase that compensates for the thermodynamic losses of aluminum. Also, the Aluminum L98 heads can be ported to flow extremely well and larger valves can be added.
The last, but not least reason, for swapping to aluminum heads is weight savings.
There are disadvantages with aluminum, like lower thermodynamics efficienies (as mentioned earlier) and it is far easier to strip a bolt or cross-thread a spark plug. Iron heads tend to be more durable and less susceptible to warping making them more desireable for long term use.</font>
Did the vette use these heads prior to '87, when the design of the heads were changed? If not, can I use them on a pre-87 block?
Member
As long as we're on the subject.. Will a set of L98 heads work on a 350, if they had steam holes drilled in them for use on a 400? What exactly are these "steam holes" anyway?
How much should I expect to pay for a set of fully-assembled used heads with low miles?
How much should I expect to pay for a set of fully-assembled used heads with low miles?
Steam holes are drilled for use on 400s, and should not affect use on a 350. They're necessary due to the "siamesed bore" casting of the 400 (that means the 400 doesn't have water passages cast in between the bores).
I've seen pairs of fully assembled aluminum L98 heads go from $400 to an asking price of $750 (new from dealer is about $800 a pair). I've got a set that I'll be unloading when my AFRs get here asking $500, not ported, stock valves, but have LT4 valve springs/keepers/retainers.
[This message has been edited by afgun (edited August 03, 2001).]
I've seen pairs of fully assembled aluminum L98 heads go from $400 to an asking price of $750 (new from dealer is about $800 a pair). I've got a set that I'll be unloading when my AFRs get here asking $500, not ported, stock valves, but have LT4 valve springs/keepers/retainers.
[This message has been edited by afgun (edited August 03, 2001).]
Junior Member
Its really not worth the trouble from what i hear...most of it is just the weight savings off the front of the car which you could get from any good aftermarket set of heads for a little more cash you could probably gain another 20hp.
lata
Bill
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lata
Bill
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The best place to get L98 heads is used. Also remember the ZZ3 and ZZ4 crate engines use these heads too.
The Corvettes used these heads from late-86 to 91. Yes they'll work fine on any small block engine, and they have the 86 and older bolt pattern.
You need heads with a larger combustion chamber for a 383 or 400 engine, or else you'll need deep dish pistons. The longer strokes really increase the compression ratio. With these 58cc heads you'll probably be over 12:1.
I've got ported L98 heads on my engine, and the car made 317 HP and 418 TQ to the rear wheels.
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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-
The Corvettes used these heads from late-86 to 91. Yes they'll work fine on any small block engine, and they have the 86 and older bolt pattern.
You need heads with a larger combustion chamber for a 383 or 400 engine, or else you'll need deep dish pistons. The longer strokes really increase the compression ratio. With these 58cc heads you'll probably be over 12:1.
I've got ported L98 heads on my engine, and the car made 317 HP and 418 TQ to the rear wheels.
------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-