L98 heads
Thread Starter
Instructor
Joined: Jul 2010
Posts: 120
Likes: 4
From: Virginia
L98 heads
Hi, Ive got a 78 vette (doin a frame off) with the 190 hp 350 (L42?) Need more hp to say the least. Ive got a set of L98 # 10088113 aluminium heads, 58cc,1.94/1.5 valves Will these heads help with maybe a Edelbrock intake and carb and a mild cam? Also will stock pistons work with this type of set up?
Drifting
Joined: Aug 2005
Posts: 1,372
Likes: 4
From: Springfield VA
I think the older motors had larger chambers so you will get a good size bump on compression.
The L98 heads are not top of the line but should flow better than what you have if i remember. Get the head number off the heads you have now, never know they could have been changed in their life. Compare the the flow and combustion chamber.
Also check the head numbers on the L98s you have. The early ones had some cracking issues. Been a while since I was a tech but L98 was the big thing when I was and I remember that much.
If they are a good set then I would run them. But yea a little bit bigger cam, not to big, and a good intake shoudl do whonders.
The L98 heads are not top of the line but should flow better than what you have if i remember. Get the head number off the heads you have now, never know they could have been changed in their life. Compare the the flow and combustion chamber.
Also check the head numbers on the L98s you have. The early ones had some cracking issues. Been a while since I was a tech but L98 was the big thing when I was and I remember that much.
If they are a good set then I would run them. But yea a little bit bigger cam, not to big, and a good intake shoudl do whonders.
Drifting
Joined: May 2005
Posts: 1,258
Likes: 38
From: springtown Texas
i used 89 vette 113s on my 350. i got the heads for free from a good friend so i just paid for a new valve job and a slight mill to get them staight. i did a little clean up porting myself. i put in a small comp cam and i'm surprised the way they perform. my comp is 11.1 :1 with a .038 quench and it runs perfect on pump 93 gas. i would use them again on a mild street motor on a budget. here they are before and after.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
i used 89 vette 113s on my 350. i got the heads for free from a good friend so i just paid for a new valve job and a slight mill to get them staight. i did a little clean up porting myself. i put in a small comp cam and i'm surprised the way they perform. my comp is 11.1 :1 with a .038 quench and it runs perfect on pump 93 gas. i would use them again on a mild street motor on a budget. here they are before and after.
Scott
Race Director
Joined: Oct 2002
Posts: 12,065
Likes: 2
From: Smalltownville Michigan
Cruise-In 5, 6 & 10 Veteran
St. Jude Donor '09
gonna go on a limb here and say the original came with 882 cast iron heads. the L-98 aluminum heads are a decent stock casting. and if i'm not mistaken, you will nneed to go with a late model intake because those heads have a slighly different bolt pattern on the intake
Drifting
Joined: May 2005
Posts: 1,258
Likes: 38
From: springtown Texas
i'm running the comp cams thumper
.479/.465 227/241 @.050 107 sep these specs are with 1.5 rockers. i'm running 1.6 so the lift is just over .500 if i remember right.
when i did the dynamic comp calc when i was building the motor it was right at 9.0:1 thats supposed to be too high for pump but i've had no problems.it could be the quench. my flat top pistons are .023 down in the hole and i used a .015 head gasket. and my pistons have a single trough. which i've read is the best for flame travel. my total timing max is 36* from @ 2800 on up.
i thought gm still used the l98 113 heads on the zz350 crate motors.
.479/.465 227/241 @.050 107 sep these specs are with 1.5 rockers. i'm running 1.6 so the lift is just over .500 if i remember right.
when i did the dynamic comp calc when i was building the motor it was right at 9.0:1 thats supposed to be too high for pump but i've had no problems.it could be the quench. my flat top pistons are .023 down in the hole and i used a .015 head gasket. and my pistons have a single trough. which i've read is the best for flame travel. my total timing max is 36* from @ 2800 on up.
i thought gm still used the l98 113 heads on the zz350 crate motors.
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Drifting
Joined: May 2005
Posts: 1,258
Likes: 38
From: springtown Texas
i used a edelbrock perf rpm intake i got used. it was on a 78 camaro with the original motor. the intake bolts right up to these heads with no problem. you can see the perf rpm in the pics.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
i'm running the comp cams thumper
.479/.465 227/241 @.050 107 sep these specs are with 1.5 rockers. i'm running 1.6 so the lift is just over .500 if i remember right.
when i did the dynamic comp calc when i was building the motor it was right at 9.0:1 thats supposed to be too high for pump but i've had no problems.it could be the quench. my flat top pistons are .023 down in the hole and i used a .015 head gasket. and my pistons have a single trough. which i've read is the best for flame travel. my total timing max is 36* from @ 2800 on up.
i thought gm still used the l98 113 heads on the zz350 crate motors.
.479/.465 227/241 @.050 107 sep these specs are with 1.5 rockers. i'm running 1.6 so the lift is just over .500 if i remember right.
when i did the dynamic comp calc when i was building the motor it was right at 9.0:1 thats supposed to be too high for pump but i've had no problems.it could be the quench. my flat top pistons are .023 down in the hole and i used a .015 head gasket. and my pistons have a single trough. which i've read is the best for flame travel. my total timing max is 36* from @ 2800 on up.
i thought gm still used the l98 113 heads on the zz350 crate motors.
bmprhmpr, what do you consider a "mild" cam?
Scott
Thread Starter
Instructor
Joined: Jul 2010
Posts: 120
Likes: 4
From: Virginia
Yall are way beyond me with cam tech. (ive only built engines with stock parts) The stock heads have a #462624 casting no.,76cc, not sure of valve size,Ive read they used 3 different valve sizes with these heads. The bottom end Ill rebuild to stock, use the L98 heads and performer intake and carb with headers. So Im lookin for sugjestions on a cam. Im lookin for 300 hp. nothin serious. Thanks for all the imput.
Last edited by bmprhmpr; Dec 17, 2011 at 05:17 PM. Reason: hit wrong key
Drifting
Joined: May 2005
Posts: 1,258
Likes: 38
From: springtown Texas
i have a isky 270 mega cam and lifters i pulled out of one of my previous 350 motors. 75.00 if you want it. i was running it with my l98 heads when they were stock, no porting and it pulled hard for such a small cam. and has a little lope to it.
the specs are .465/ .465/ 222/ 222@.050 108lsa
the specs are .465/ .465/ 222/ 222@.050 108lsa
Race Director
Joined: Aug 2004
Posts: 10,628
Likes: 132
From: Duvall, WA
I put L98 heads on my '71. They were a nice performance improvement over stock, with good low end torque. Though you'll need center bolt valve covers, a stock type of intake manifold will bolt up just fine. The heads have no heat crossover, which may affect your choke set up.
Drifting
Joined: May 2005
Posts: 1,258
Likes: 38
From: springtown Texas
i bought the cam used from a friend so i don't know the milage on it. i bought the lifters new and put @ 2000 miles on the cam and lifters.
it's a flat tappet hyd.
i went with a bigger cam, thus the reason i don't need it anymore.
it's a flat tappet hyd.
i went with a bigger cam, thus the reason i don't need it anymore.
1st Gear
Joined: May 2012
Posts: 1
Likes: 0
help
hey, was woundering if any of you new were i could get the inner spring if thats what you call it. i was upgrading my valve covers and looked inside and found a piece of a spring (not the heavy rounded spring) but the flat one inside of the heavy rounded valve spring. ive been looking all ove the place and havent even seen them. every time i type valve spring for 10088113 it gjust shows the outside spring. help.
thanks
kerry
thanks
kerry
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
imo the Isky 270 will run circles around the thumper from a leave and be much easier to drive with that head/intake. Great all around street cam.
Some of the old tech flat out works.
Some of the old tech flat out works.
