I've never delved into the internal components of my engines in the past so this is all new for me.

I'm looking into getting a top end kit for my C3. Both of the options I'm looking at state they're for engines w/ a 9.0:1 compression ratio for max results. A quick google search shows that the C3 from the factory had a compression ratio of 8.2:1

Do I need to continue upgrading to the 9.0:1 point or am I safe to go ahead and install as is?

If you're unfamiliar with my posts in the past. The car hasn't driven in 15'ish years, it has run in the past few months since I've gotten it, but I'm not confident in road testing until all appropriate maintenance has been done. I know this isn't maintenance, this is definitely a want not a need.




After some super sketchy math that would make engineers cry. I estimate that at 8.2:1 instead of 315 HP, I'd be looking at roughly 285HP max

solve for Z -->



315 (Max HP @ 9.0:1) Z (Max HP @ 8.2:1)
------------------------------------------ X -----------------------------------------------
9.0 (Called for Compression) 8.2 (Current Est. Compression)



315 ÷ 9.0 = 35 (HP / Comp)

35 x 8.2 = 287 (Max HP @ 8.2:1 Compression)

 

Your stock heads are 76cc
the estreet heads are 64cc
the result would bump your CR by about a point.
so 9.0-9.3 range.
theres some calculators online if you want to figure out the exact number. But low 9’s will be the ballpark.

In my opinion, the camshaft in that kit is too small(it’s just a little bigger than stock). But just depends on what you want out of the car. The heads are great tho.

 

@randallsteel

I'm looking for a boost in HP but nothing crazy, just a confident V8 not the 190 HP that left the factory. I figure I daily a Dodge Journey 2.4L w/ 178 HP so the Vette should definitely have some more umph to it.

 

2400 for a flat cam kit..
blueprint engines new long block is like 4200 and a roller cam..390 hp.
have you opened exhaust, timed for maximum performance? It will really change you engine from stock.. and the exhaust you will use in any direction you go, timing vacuum advance cheap.
do you have original electronic carburetor?

 

I put this exact kit on my 75 L48 in 2019 and overall I was pretty happy with it, big improvement over stock. Much more responsive, especially accelerating from highway speeds.
But the cam did disappoint, after about a year I put in a bigger cam, and flat top pistons.

Im not too sure what intake you got on right now, or what carb, but I would check to make sure the edelbrock intake in the package works with your carb. There are spread bore and square bore intake/carbs.

when I bought it in 2019 I remember it was $1700 AND it came with a free avs2 650 carb

 

That cam is too small.

Get a comp 268HE cam, a set of brodix, AFR, or Trick flow 180-195 cc heads with 64cc chambers, longer hardened push rods, and 1.6 ratio roller rockers.

 

See how everyone has there opinions?
Aren't forums great!
If your a novice these kits keep it simple.
And yes they work.
And yes there are a ton of other ways to go.
But these kits do work and they keep it simple for the novice.
And yes you could buy parts separately and come out with more power. However many inexperienced individuals have purchased parts separately, came out with a poor combination and made less power.
If you assemble this kit as is your compression will rise about a point as mentioned above. Putting you right where you need to be.
So,
do a LOT of research and learn what works with what. Or install one of these relatively mild kits that are fairly safe.
Your call, your car.

 

Don't bother using that kit if you are going to use that cam.......huge waste of money.
At least the 268H cam......

Jebby

 

I think we are all saying kits are great, but most of us are saying, buy the same pieces just a different cam. Here all the parts for the kit, all available on summit or jegs.

Estreet heads #5089 -$1300
edelbrock head bolts #8550 - $175
edelbrock pushrods #9629 - $187
felpro gasket set 260-1000BT -$86
Comp cam XE268H -$300
Edelbrock performer intake #2101 -$300

I think that’s everything in the kit. And total is $2348. But much better cam.
just giving you some options.

 

You can save about $200 using ARP bolts and Trick Flow/Trend pushrods......you cannot buy pushrods until you check the length. True engine builders would never use a top end kit from Edelbrock......their markup on ancillary components is silly.....but they market to the uninformed as if you "have" to have "their" special components.....which are all made by outside suppliers.....

Jebby

 

Jenny is right. They make these kits for station wagons, pick up trucks etc.building an engine for a target horsepower isn't going to work out. Vehicle weight. Gearing etc all factor in plus how the car is driven.
The so called experts aren't as expert as you think. I've had major cam companies come up with some really lousy suggestions.

 

Im actually contemplating the same / similar kit for my 82. It I’d need the Holley sniper kit to get it to work due to the “efi.” I’m looking at their 338 hp kit and that’s enough for me. I’m more of a handling / curvy road kinda person as opposed to drag racing.

 

Interesting.
9 to 1 ain't bad and get a bigger cam like suggested.
Have you replaced the comp controlled stuff?

 

You do not have to put EFI on the car because it has EFI now.....although there is no problem doing that....know that little of the original EFI will be retained.....
Road curvy people have much more fun at 400hp than 338hp.....trust me......
The thing that gets me is that there is literally no negative to installing a larger cam to support the cylinder head and intake......I mean....you are buying them anyway and only using 70% of the potential......a lot of airflow potential and then you stick a cam that is barely bigger than the L-48 cam......just buy a Vortec head 350 crate engine for the same money and have a fresh engine......

Jebby

 

i actually do. The crossfire wouldn’t be able to function with the engine mods. It’s very finicky on what it can do. And it definitely wouldn’t work with a replacement motor.

 

Putting the CFI will never allow the engine to make more than about 240hp as the intake is seriously restricted......the Renegade intake solves this problem but has been out of production a while (Although the creator of it is trying to get it back in production). The creator of the Renegade intake is a member here and a CFI expert......his own CFI equipped Vette runs 12's.......the system is only finicky if it is left stock, and that would totally defeat the purpose of putting a $3000 top end kit on an engine that won't support it......just rebuild the stock stuff if you are going in that direction......lot of money for little benefit.....
You would have a 338hp engine with a 240hp intake....and it would make 240hp total after all of the mods......GM found this out on the 1982 Z/28 Pace Car that they modified for the race......it had an all aluminum Bow-Tie engine in it capped by the stock CFI.....it made 250hp.

Jebby

 

Youre 100% right. The edelbrock kits also come with a new intake. Like you said, stock one is garbage, so a new one is definitely required. I’d rather rip out the crossfire and put in the sniper with a new intake, heads and cam. That’ll make the difference.