hey guys my vette isnt in bad shape the engine has about 40 000 km on it and i need some more power. i was looking on summit and came across this:

http://store.summitracing.com/partde...0&autoview=sku

will just changing the heads and a cam actually give you these kind of numbers...or is that assuming that you have upgraded the ignition, intake, carb? the exhaust is already a true dual 2.5 inch setup.

 

The kit looks pretty good, but I would be surprised if it actually made 500hp...thats quite a bit for a naurally aspirated small block with relatively small heads. I would say 450 or so would be more realistic with a streetable compression ratio and all the bolt ons (single plane intake, 1 3/4 full legth headers, a good ignition system, and the right carb). Dual 2.5s will be marginal, but you can get by with it.

 

When looking at the claimed output numbers for those kits, you also have to pay close attention to what bottom end they used to get those numbers. In most cases, the Trick Flow top end kits that offer big power and torque numbers are tested on top of a 9.5 or 10:1 383 ci stroker motor.

That's perfectly fine if you're running the same but those same components may not (likely will not) match very well with, say, an L48 bottom end. To get those 500 hp, they need more displacement and things like a big single plane intake and big cam...that may not be the MOST usable on the street and may be more intended for track use.

Again , these are just my observations, having looked at Trick Flow top end kits, as well. If it seems too good to be true (and you're assuming you can bolt on 500 hp to your 350), it probably is.

EDIT: If you have a print catalog handy, Summit DOES state that the dyno results for this motor were generated with a 383 ci bottom end. That changes the game significantly from "throwing these parts on your existing bottom end." I'm not saying they're decieving people but I bet this does confuse some people.

 

Those are only 72 cc chambers. You wouldn't ave enough compression to make much more power, I think the stocks are 76 cc, buy my understanding the cam would be way to big for the compression you would have. A smaller combustion chamber on top of your l48 dished pistons and a little smaller cam would be more streetable and make better horsepower. Others should chime in also but as ajkogut said they were using a 383 most likely with flat tops and a zero deck block. I have the holley systemax kit on my l48 style crate motor and I camed down a little bit (less duration) the one that came with it was still to big for normal street driving romping and good low end performance.

 

Your gonna want a 62cc or 64 cc chamber to bring the CR up. You didnt specify an intake manifold change either. Do you plan on using the Q-jet car?

 

72cc chamber, 195 runner heads, 246/254 at .050 hydraulic roller.
all this stuff is ment to go on at least a 383 size engine with
very good compressioin. You put this on your 350 you will have a real
mess.

 

Tell me about it.

 

that cam is way too big for the street,great cam for the street is a comp cam 268 or 268 extreme,biggest cam for stock converter,but i would install little higher stall converter then stock [1600-2000]i made a mistake by taking out the 268 extreme for a 280 cam,even with 2400 stall converter,does not idle real good in gear still,but installing 4 speed soon,stock heads are only ok,you can use pop-up pistons to raise compression or install double hump heads with 2.02 valves or something like 170-190 cc intake runners 2.02 heads 64 cc. 3.70 gear would help,if you don't mine passing everything but gas stations

 

hey guys thanks for hte input and sorry about the delay...i work long days and dont have access to a computer until late...so prety much the trick flow top end is a no-no...my goal by the time im done with the motor i want it to push somewhere around 350-400 at the wheels to throw it hopefullly into the low 12s...so im thinking about changing the carb and ignition to start off with...what do you think my best bet is...something around a 700cfm? full MSD?

 

or should i get a set of smaller chamber vortec heads and change the cam as well...what kind of numbers would i see with both setups...which has more bang for the buck?

 

If you're looking for low 12s, I'm thinking you will need something more serious than the Vortecs mentioned below. Also, I just noticed that the cam that comes with the kit is a hydraulic roller...unless you have a hydraulic roller later block in the car, it won't work, at least not without spending a lot of extra money. If it were me, I'd buy a good core roller block, get an Eagle or Scat 383 rotating assembly (cast would be fine if you didn't plan on any power adders), and use a similar head to the Trick Flow (there are tons of choices out there), but with a cam with less duration than that, esp if you are running an automatic. You could make the 450-500hp its going to take to run the numbers you want, and the 383 will be far more driveable as opposed to a similarly-cammed 350. Plus, you'll gain a lot of torque. Granted, this isn't a cheap solution, but you could likely build the short block for about $1500, and sell (or mothball, if you're into keeping the original parts) your original engine to recoup some of the cost. Just keep in mind that if you go this route, you're going to have to beef up the transmision and convertor, and possible the rearend as well to make everything work well together and prevent any drivetrain breakage. A combo like this is going to want at least a 750 (I'd go with an HP series Holley myself), and a good ignition system too, esp if you bump the compression (I would). MSD, Mallory, Crane and others all make good ignition parts...go with your preference!

 

i want to try and stay away from having to completely taking apart the engine to put a new rotating assembly in. i was looking at these ignitions, manifold and carb.

carb
http://store.summitracing.com/partde...5&autoview=sku

manifold
http://store.summitracing.com/partde...P&autoview=sku

ignitions
http://store.summitracing.com/partde...5&autoview=sku

http://store.summitracing.com/partde...2&autoview=sku

am i on the right track with these? or can you suggest somethign better

 

That carb is pretty big. I have that on my health 350 and it runs a little rich. As for the distributor I have the msd e-curve and like it a lot. There are not springs and wights the advance is all electronic you set it with dial switches under the cap. Then hooked up to that I have a MSD 6A box. No need for the 6AL or higher since the e-curve had a rev limiter built in.

e-curve
http://store.summitracing.com/partde...5&autoview=sku