I am replacing the lifters and cam in my '81. I would like to install a cam with more performance but not lose the driveability. What are the specs on a L82 cam and what other cams should I consider? Thanks, Eric
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Re: C3 Cam Replacement
The problem with using the L-82 cam (which by the way is a great cam) is that your 1981 does not have the compression ratio to support it. That cam would really like to have at least a SCR of 9.75-10.0 to run nicely. The very basic specs for the L-82 are: L-82 (G.M. #3896962) 224 degrees @.050 and .450"/.460" lift and a 114 L/S. Is this car an automatic and does it have a 3.08 ratio. If so, a popular cam kit over on the Corvette Forum for the L-48 is the Summit 1103K. I can not vouch for it's performance or characterics.
Duke has modeled the L-48 cam and it will add some RPM range and performance if you retard it 4 degrees upon installation. -
Re: C3 Cam Replacement
Scott, it is an automatic stock L81. I am uncertain of the ratio. Thanks for the info and any other help you can provide is appreciated. EricComment
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a big help on these cars is a higher stall speed
convertor which will help the bottom end a lot. you can install a GM V-6 convertor.Comment
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Re: C3 Cam Replacement
As with any other production Corvette engine, the BEST SINGLE MODIFICATION you can make is to massage the heads, which has been discussed a zillion times.
I wish I knew that 40 years ago!
This will increase top end power and useable revs WITHOUT affecting idle characteristics or quality and with viturally no effect on low end torque.
Further improvements in top end power at a slight loss to low end torque without affecting idle quality can be had by retarding the 3896929 cam by degrees.
IIRC the L81 is a closed loop system with an "electronic feedback carburetor" and O2 sensor, and I'm not sure it is uses the same "929" base engine cam as was used back to '67. According to the NCRS Spec Guide, with TH350 the axle was 2.87:1 so you DO NOT want to sacrific any low end torque.
If this is an O2 sensor feedback system you can still massage the heads with no ill-effect, but if you mess with the cam you could end up with a nightmare on your hands.
DukeComment
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Re: C3 Cam Replacement
Duke----
1981 originally used the GM #3896929 camshaft.In Appreciation of John HinckleyComment
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Re: C3 Cam Replacement
Joe - can you also confirm that the '81 L-81 has an 02 sensor and TWC with an "electronic feedback Q-jet".
DukeComment
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Re: C3 Cam Replacement
Duke-----
Yes, it does.In Appreciation of John HinckleyComment
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81 corvette carb
81 corvette used a E4ME solenoid mixture controlled carb. 17081217,218 and 228 depending on aplicationComment
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