Kurt Crosbie

I think I'm ready.

Here's what I have done so far.

355 forged
6" i-beams
clevitte h-series bearings
stock forged crank
ross 90450 pistons
impala ss head gaskets
11.3 compression ratio
home-ported heads
1.6 rr's
comp lifters
comp 987 springs
gm847 monster cam (the thing I want to change)
cold air intake
custome 3" dual exhaust with x-pipe and bullets
electric water pump
spec stage III
stock rear end with 4.10's and girdle reinforcement
I think my only bottleneck is my 24# injectors. I will be replacing them soon.

Anyway, where should I go for a custom grind? I'm pretty show I don't want to go with comp. My buddy ordered a custom grind for his 10.3 382 setup and they sent him an off-the-shelf 233/239 based on the gm847. I don't see what was so custom about that. Anyway, please guys, point me in the right direction. I want to max out what I have with a good cam. I want whatever is going to get me down the dragstrip the quickest without going overkill on rpm's ( I want the motor to last a little while at least). I figure I can safely turn 6500rpm when I go to the strip with the 987 springs.

blackztpi

talk to bret bauer. great customer service and the cam hauls serious ***. he can make you a happy man

Purplemaroz28

get your heads flowed.... This way they can match a cam to the amount that you heads flow

Jon A

Why go through the hassle of getting a custom cam and installing it when you've tied the hands of the cam designer in such a way? I'd also give Brett the thumbs up to fill your needs, but expect those springs to go.

blackztpi

a lot of bret's cams come with springs for a good price. in fact, he highly recomends his springs, AND he gives a 40 dollar discount on the cam if you buy his springs. my bauer cam came with comp beehives. i like the setup soo far!

Kurt Crosbie

Damn, I thought 987's were good springs. This sucks.

I figure if the 987's are rated at .600", then they have a safety of about .050". Is this not correct?

How high can I spin it and still be safe?

At what rpm will my hp peak?

What should my shift and re-engage points be?

Kurt Crosbie

Where would I go to get the heads flowed and how much would it cost?

turbo_Z

You are in NC... isnt there a high performance speed shop on every corner in that state!? I know Advanced Induction is in NC somewhere and would probably flow that head for you.

EDIT. They are in Concord

Kurt Crosbie

There are a few speed shops here. Most of them are around Charlotte, Concord, Mooresville, Huntersville, etc., which are in central NC. I am about 2 hours away from there.

Jon A

I'm sorry, I didn't mean to imply that the springs were "bad" or anything. Just that if you go to a cam designer looking for a custom that will make your car faster than the GM847, it can surely be done--but it could turn out those springs will not be optimum for whatever he comes up with. If I was going through all that trouble (and I'm in the process of doing it the second time now ) I'd let the expert pick the right springs to match. Having them set in stone because it's convenient is giving the cam guy fewer options, that's all.

Yes, they're safe to .600" with .050" clearance when installed at 1.80". But they're only recommended for .500" max lift. At 1.80" you've only got 121 lbs on the seat which will limit how quickly the valve can close without bouncing and at what RPM it will occur for a given profile. And I should really shut my hole right now and let the more knowledgeable take over. I guess I'm just bored tonight.

And I guess sometimes I don't understand the lack of priority some put on such a critical valvetrain part. Big money in the bottom ends and everywhere else, but many seem resistant to pay enough attention (IMHO) to this particular part. Yes, springs cost money and yes they're a major PITA to change when on the car...but I think it's a place that deserves more time/effort/money than most are willing to give it.

SStrokerAce

Jon you're right about the springs.... hell most of the valvetrain is neglected. Pushrods are another neglected important part of the system.

Two things that a cam is directly related too that guys should understand is the compression ratio and the valvesprings..... both of those things will limit what you can do with the camshaft. In the case of comrpession, the more the better the bigger the cam you want to run... realitively. I normally see guys who want a big cam don't have enough compression to run something that big with optimal results.

Bret

Kurt Crosbie

Is 11.3 a good compression ratio? Do I need to go higher. I think the impala ss gaskets took me as far as I could go with the ross90350 pistons and 6" i-beams. anything over that and I'll be looking at a .020" quench.

SStrokerAce

Kurt,

What is the rest of the deck height measurement? How far are the pistons down in the block?

11.3:1 is decent, you can get a 355 into the 11.7:1 range but that's only really needed if you want to go high rpm/big cam or you want to push the limits of dynamic compression.

Bret

Kurt Crosbie

I believe my quench is .037". Isn't that the distance between the top of the piston and the head?

Kurt Crosbie

I could change the pistons out to change the compression ratio, but I'm not sure if I want to go through all that trouble. Then there is the issue of this being a 2-bolt main block. I think maybe I should keep the power right where it is because this block can't hold too much longer. I think I'm pushing 450hp right now and thats as much as the 2-bolt can take. I know its forged and everything, but the concept of just 2-bolts holding my main caps down is not very appealing to me. I figure the next time I pull the motor I will splay the caps, change the pistons to get up to 12:1 or as close as I can get to it, and get an aftermarket (baffled) oil pan. I dont know what else I need to do. I think with caps being splayed and going up to 12:1, I don't really know what could go wrong. Keep in mind it is a longrod 355. I believe that means less reciprocating force on the crank.

There is one more thing. Maybe I should go with some h-beams to stiffen it up a bit. But do I really need to worry about h-beams if I'm only going to be making ~525fwhp?