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Discussion Starter · #1 ·
Heard a rumor that in 1980 vettes used a 305h sbc motor is this true,and also this motor was also used in the camaroz28 and firebird tans am.Being a trans am owner with the 305h motor 1981 wonder if this is the same,is there any way to find out if this is true.And also was this motor use in other applications.
 

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According to the " Idaho Corvette Page " (found on the internet) the 1980 Vette came with 3 engine offerings. You can tell which one you have by the 5th number or letter in the VIN. Number 8 = 350 ci 190 hp.... number 6 = 350 ci 230 hp and the letter H = 305 ci 180 hp. Dont know the other items but you can probably find them doing a search
 

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I new the Vettes used a 305 in '80 and while I never saw a 1980 Z/28 with a 305 in '81 it was the only way to get a 4 speed in the US. I bought one new, trust me they were nothing special. :embarrass :(
 

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stoney 81ta said:
Thanks Hippie just i was wondering how to find out if i got the same 305 h in mine would a vin check tell me.
I can just about guarantee they are the same engine, maybe a different code letter because the application is different but the compression ratio, heads and cam would be the same. I can tell you a cam swap did wonders for my '81 but even with no AC, a 4 speed and 3.42's it was still a slug. A "faster" slug but a slug just the same.
 

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The 305 in the Vette, indicates that it is a California car. Because of tightened Calif. emission restrictions, Chevrolet did not certify its 350 engines there in 1980. Calif. Vette buyers were required to purchase a 305 engine, the RPO LG4, with a $50 credit. This was a standard passenger car engine, built at Chevrolet's Tonawanda, New York, engine plant.

Dan
 

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Discussion Starter · #8 ·
Thanks Dan, but why was the vette 305 rated at 180hp and the other 305's at 150hp if i have the same engine code h how can i get the ther 30 hp. And also acccording to another site the lg4 was introduce in 1982.
 

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stoney 81ta said:
why was the vette 305 rated at 180hp and the other 305's at 150hp
Because it was in a Corvette, it was all a numbers game for the consumer. Chevy couldn't have a lowly Camaro with the same HP as "mighty" Vette so they juggled engine accessories and exhaust to effect the dyno results and give the illusion the Vette 305 was something special which it was NOT. Don't get too hung up on factory HP ratings they're about as "real" as reality TV. You want that "extra" 30 HP? Change the cam, intake manifold and exhaust and put a recurve in your HEI. You WILL notice a difference. Oh yeah what's your car have for gears? If it doesn't already have them a set of 3.42 - 3.73 gears would be your next best "bang for the buck".
 

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stoney 81ta said:
Heard a rumor that in 1980 vettes used a 305h sbc motor is this true,and also this motor was also used in the camaroz28 and firebird tans am.Being a trans am owner with the 305h motor 1981 wonder if this is the same,is there any way to find out if this is true.And also was this motor use in other applications.
You may be thinking about the LM1 engine that was used in the '80 Camaro Z28. It was a 350 with 180 hp - same engine as the vette.

This is a good write up on the LM1's: http://www.nastyz28.com/camaro/z28lm1.html
 

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The rag-mags did a buildup on a 305 that put out 340 hp with good vacuum and made the slug into a turtle. 340 stick shift car will run fairly well.

There is the supercharger whine, the cam gear whine, and the turbocharger whine.

Watch out for the Chevy whine..... "My big block 502 with 200 nitrous will kick your 5 liter's a****".
 

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Stony,
Hippie has it partially right. The HP numbers are net and specific to the car they are in. The Vette usually has a better induction and exhaust ( breaths better) so the numbers are usually higher in the Vette. That being said, I don't think that would make up 30 hp, maybe half of that.

Dan
 

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dt196 said:
Stony,
Hippie has it partially right. The HP numbers are net and specific to the car they are in. The Vette usually has a better induction and exhaust ( breaths better) so the numbers are usually higher in the Vette. That being said, I don't think that would make up 30 hp, maybe half of that.

Dan

The last year the Vette and Z/28 got a "good" intake until TPI came out in '85 was 1972. :( The Vette had better exhaust in the later model years but used the same Q-Jet carb intake manifold, it may have had a dual snorkle air cleaner but it was still restrictive, not something I'd go looking for. Besides you have a TA, I don't remember if the '81 had a functional hood or not but you could sure make it that way with parts from an older one. The '80 and '81 Z/28 hood was "functional" but the opening was so small and the airway so restrictive it was all but useless.
 
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