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So to get a little more power out of my stock 93 LT1 I was thinking something simple and not too invasive. I was considering maybe some 1.6 rocker arms. Can I just bolt some on or do I need screw in studs, other valvetrain hardware, etc? Do I need the narrow bodied self-aligning Scorpion rockers or are there some others I should consider? I may stab in a mild cam kit, freshen up the heads, do some port matching, smooth out the runners, etc. as a winter project but for now I'm not looking to pull heads, exhaust manifolds, or break stuff if I can avoid it. Thanks!
Budget is flexible but I want to do something relatively simple but cost effective for now. Don't want the car torn apart all summer. That's why I was thinking about the 1.6 rocker arms. Skill level....decent mechanic. I can take apart and build an engine. Marginal electrician. I give myself a 7 out of 10.
I'm a believer in all the small stuff adds up and you want all the supporting mods if you add a cam later. The heads already have screw in 3/8 studs. The weak point are the valve springs and it is recommended you upgrade when switching to 1.6's. A good cold air intake, throttle body bypass, 160 degree thermostat and a bolt on tune/chip would be an easy start. Next would be the exhaust.
I should have mentioned, my car is a 6 speed so it has 3.45 gears. I think some 3.90s would be fun without going overboard. Will 1.6 rockers work on stock springs for now? When I do the cam later I would pull the heads off and freshen everything up then.
I'm not going to say it won't work because people have done it but not recommended. The problem lies in the weakness of the spring as it only has like 85 # of seat pressure. The stock power band falls off around 5500 rpm and the whole purpose of adding the 1.6s is for power. Even though they add .030" more lift it won't raise the powerband rpm with weak springs. The heads are decent in stock form and will work with a variety of cams, it depends on want you want.
Sounds like I need to leave the motor alone until I'm ready to pull it apart and do all this work at the same time.
The 92s and 93s are almost the same. There was a very minor camshaft revision in 93 which is supposed to give it a little more midrange torque. But they both run the same speed density ECM which was changed to MAF for 94-96
My 92 6 speed has 1.6 Scorpion narrow body RRs, stock valve springs, LT headers. Cat delete, X pipe and glass packs. It runs 13.2 @105mph in the 1/4 mile.
My 93 6 speed has stock rockers, stock valve springs, stock exhaust manifolds, cat delete, X pipe and glass packs. I haven't run it at the track yet but power feels about the same.
Both cars have a mild tune. Basically a "mail order tune"
These engines respond well to freeing up the exhaust. The cats on the LT1s flow much better than the ones on the L98. But in both cases you want an X pipe and glass packs for power.
Both L98 and LT1 stock exhaust manidolds flow well and are capable of producing similar power to LT headers on a relatively stock engine. I don't think the effort or expense of installing LT headers is worth it on a stock engine. If I knew then what I know now, I would not have bothered to install headers on my 92.
Dave
Last edited by C4industries; May 23, 2025 at 08:44 AM.
Well see, a successful user of 1.6s with stock springs. I totally agree with C4's exhaust setup as it is exactly what I did with the exception of fabricated short tubes with a modified collector, a Dr. Gas X pipe, mandrel tubing and 4 Magnaflow mufflers. My Lt1 engine woke up adding 17 rwhp with that system. It works well and sounds good. My prior system was 2 1/2" ramshorns manifolds, H pipe with Dynomax mufflers.
C4 have you ever stuck that 1992 on the dyno?
I have a 93 and it has all the stuff ya talked about (stock cam), headers, 1.6 rockers open exhaust ram cold air HD springs Etc. retuned O-YES runs way better, reminds me of a LT-4 I owned years back .. Now bang for the buck 390 rear gear with a 6-speed O-yes one of the best mods I have ever installed in any C-4 stick manual vette .. I tired that in my 93 auto no way too low for me ,if ya just want to burn rubber even the 373 was a little low for me in this auto, now around town was great pull ya back in the seat for sure at 70 the RPMs were around 3200 not much of a HI way vette for me. so went with 307 just right on the road, still peppy. but the 390 with 6-speed you'll love it, best of both worlds, all that stuff you're thinking about doing with the 390 kinda like that's what ya did ,now I have heard of people putting in a 410 ,I don't know that deal say it's great ??? Just saying cut to the chase lower gear.
Runs good lot's work ..
You have me thinking Dave. I wonder what a tune like yours and 3.90 gears would feel like.
I like to do the mods that "need" to be done first. So, if you want more power, and who doesn't?...then I recommend the exhaust work (X pipe and glass packs) first. It's also relatively easy and inexpensive.
I haven't taken any of my cars to a chassis dyno yet but if I make power mods I try to get to the 1/4 mile track to verify results. I find the standard 3.45 and even the 3.33 manual ratios to be low enough to hook up and launch well. I never felt the need to go lower for the type of driving I do. My 90 has 3.33 gears and 19" wheels. Overall, that makes it about 10% taller than a 3.45 gear with stock 17"wheels. It still hooks up and launches well with a respectable 1.97 second 60' time. It will also effortlessly cruise at 100mph @2000 rpm in 6th gear. Plenty of grunt and no need to ever downshift until you drop below 80mph. Gotta love that TPI torque and the double overdrive on the ZF6.
Last edited by C4industries; May 21, 2025 at 11:19 PM.
A few more ponies....
