L98 performance heads
Instructor
Joined: May 2003
Posts: 183
Likes: 0
From: San Jose CA
Re: L98 performance heads (Fast_vette89)
The best heads for an L-98 are the AFR 190cc heads with 2.06 intakes and 1.6 exhausts. They come fully assembled and can take more than .550 valve lift. On every head flow test I've seen the AFR flow numbers come out on top.
They also have the best exhaust to intake flow ratio I've seen. I have them on my engine and that 355 puts out 500 ft. lb of torque. Downside of AFR's is if you race you have the build an oil contol system. Oil returns are higher than on factory heads so at least a quart of oil is trapped in the valve covers at high rpm. Oil will leak out of ANY baffled breather. I have the problem solved now. I think they cost about $1200 per fully assembled. Compare that to having your heads ported. FWIW.
Larry
They also have the best exhaust to intake flow ratio I've seen. I have them on my engine and that 355 puts out 500 ft. lb of torque. Downside of AFR's is if you race you have the build an oil contol system. Oil returns are higher than on factory heads so at least a quart of oil is trapped in the valve covers at high rpm. Oil will leak out of ANY baffled breather. I have the problem solved now. I think they cost about $1200 per fully assembled. Compare that to having your heads ported. FWIW.
Larry
Team Owner
Joined: Sep 2001
Posts: 62,180
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: L98 performance heads (larrybsp)
Downside of AFR's is if you race you have the build an oil contol system. Oil returns are higher than on factory heads so at least a quart of oil is trapped in the valve covers at high rpm. Oil will leak out of ANY baffled breather. I have the problem solved now.
Drifting
Joined: Dec 2002
Posts: 1,861
Likes: 4
From: Houston TX
Re: L98 performance heads (larrybsp)
While the AFR's are good heads, I just got a set of 113s to flow the AFR 190s exhaust and 10 down on the intake at max lift. I don't have the low lift numbers in front of me, but I know they're comparable to the 190, and the intake runner on the 113s are SUBSTANTIALLY smaller, meaning that you'll make more power (easier for the engine to develop the required pressure drop at IVO). I haven't CC'd the ports yet, but they started at 163 cc's. Also, the flow I got was with 2.00" intake and 1.56" exhaust valves (using LT4 valves).
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: L98 performance heads (Fast_vette89)
You can modify your #113s to flow very well with 2.00"/1.56" swirl-polished & back-cut SS valves, valve job, pocket ported and slight unshrouding of the intake valve.
Put some ProMagnum RRs, 7/16" studs, Ti retainers (no oil shedders) and 10deg locks with springs to match the cam.
Put some ProMagnum RRs, 7/16" studs, Ti retainers (no oil shedders) and 10deg locks with springs to match the cam.
