ETM

Technically that is true.Though the 1980 California Corvette came with a 305CI engine that was rated at 180HP.That rating has been disputed by a few people who have driven Cali `80s`s.That same engine in other Chevy`s was rated at 160HP.Just a thought.

Tom73

Well....yes and no. The '55 was rated at 195hp but that was a GROSS HP rating. The '75 was 165hp and that was a NET rating. So I would say that they were very close with maybe the '75 having the edge

tom...

cosmicvette

Some very cool info here....I love learning more about these cars ....I wish I could have studied corvettes at school or uni...

Alwyn678

SLOW

ACECO

If memory serves the 5th "digit" of the VIN is either a J or a T. J = L-48 and 165 HP rating. T = L-82 and a 205 HP rating. Don't remember for sure if it's the 5th digit, but the J and T info is accurate.

Losing the dual to single cat to dual exhaust system in favor of a true dual system is proported to add upto 25% to these numbers. I can't attest to any hard numbers myself, but it did make a very noticeable "seat of the pants" difference on my 75. FWIW.

Good luck w/your mods.

1975Stingray

Thanks for all the great info! Doing the Brakes this weekend. Maybe I will have some money left over for the Dual Exhaust, then Turbo Muffles, then Heads, then cams, then well I would would like to change everything with the exception of the block and trans!

flood

And everyone talks about their HP number but we all know that torque wins races. I think I read somewhere (can't find it now) that the L48 in 75 had around 255lb/ft tq.

I have done a gtech for HP on my L48 and it showed right at 165hp and thats at the wheels I believe. Its based on weight and time/distance. This is at 5000ft ASL. Best time so far is 15.8@90something. At sea level thats going to drop ~1sec. So it woudl be a low 15 or high 14. So its not too bad for being detuned. Its enough power to be enjoyable to drive.

Besides all of the stock corvettes from the C3 era are dogs compared to the new ones (C5-C6) except of course the L-88.

1975Stingray

This may be a stuipd question but when setting the timing for peak performance did 1975 have the HEI? I've never set the timing this car; can I get a set of springs at NAPA? Also I was going to purchase a timing light, any suggestions? Thanks Tom

Maymyvetteliveforevr

Yes 75 did have HEI.

theandies

I seem to remember an engine in 1970, '71 and '72 called......huummmm........lets see......LT-1. That engine my friend was no dog.

golilgto

i have a 75 C3 L48, what a dog! i have a dual exhaust system to instal,
but would also like to learn the recurve info.

dath

Couple of things just to try to steer you straight here If you are concerned about originality (like as in NCRS style), you cannot change anything. A numbers matching car is just that. *ALL* numbers must match. Of course there is always middle ground here, but for the originality freaks out there, changing little things devalues the car as they would have to change them back at possibly great expense as finding some original parts can be a pain.

Myself, I threw originality to the wind, my car was a Mr. Potato Head, so I figured why not mod it. . .

To answer your immediate questions, I would highly recommend getting an adjustable timing light as they are very handy and worth the extra expense if you fiddle with cars a lot. I have the chrome Sears one and I'm happy with it.

The '75 was HEI. I would imagine that NAPA has a recurve kit, but I got my kit at a local speed shop myself. Otherwise you can always order one from Summit Racing online.

Regards,
-dath

1975Stingray

Thanks Dath! My father was an originallity freak and never truely enjoyed his cars. Me on the other hand start the modifications right out of the box! So I think some of "corked" up parts are going to come off!

flood

I shouldn't have used the word dog, because that simply is not true. I have just been reading specs on the newer cars, and sometimes its just overwhelming.

MotorTrend
1970 LT1
0-60 6.7sec
14.5sec 1/4@99.5mph
Top speed 120
Braking 60-0 140ft
Maximum Lateral g's .75gright .78g left

C6 Z06
0-60 3.5
1/4 11.5@ 127.1
Lateral acceleration 1.05 g avg max 1.18g
top speed 198mph
braking 60-0 104ft

Mike Mercury

as expected, Tom comes through with more exacting info.

glen242

Sears timing light - the clamp on plastic inductor for the #1 wire slipped down near the headers = melted inductor clamp. Replacement cable from Sears = $45.

Hooked it up and kept the inductor clamp up near the distributor. Clamp starting melting again! Now I know the 383 puts out more heat than the 350 but WTF? BTW, the engine runs 195* water temperature at idle.

I would recommend a dial back light with a metal inductor clamp. My old non-dial back has a metal clamp and I never had a problem. Guess I'll use it, along with the damper, which is marked out to 60*.

big_G

Put a 500 hp, small block 427 in the '70 vette, give it some traction...the numbers would be close....

theandies

Look at the crappy bias ply tires they were running back then. Granted the technology of today is great and has finally caught up with the old muscle car power. It only took GM and others 30 + years to do it with all the smog requirement and CAFE standards.

mandm1200

I wouldn't call the LT1 a dog either. If the engine were rated the same way today's engines are rated for horsepower, it certainly wouldn't give an owner any bragging rights. Throw on the 2-1-2 CAT system GM was using in the 70's and the accessories, and the LT1 would have been lucky to have 300hp.
The 1/4 mile numbers speak for themselves. That high powered LT1's numbers are much, much closer to a mid 70's L-48 (with the 2-1-2 exhaust) than it is to the Z06.

HDFLH67

Check your state inspection requirements before you spend big bucks on your exhaust. Some states are very specific. Even if you are exempt from emissions testing, you may still need a catalytic convertor, AND your exhaust may need to be in it's original configuration! Check it out first!