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-   -   Big Block Chevy Intake decision (https://www.offshoreonly.com/forums/general-q/76200-big-block-chevy-intake-decision.html)

bryanspeedracer 04-15-2004 08:54 PM

Chris,

I DO NOT want to upset or alienate anyone that has been friendly enough to give advice based on their experience.

Having said that gentlemen, Chris knows his stuff. He just won't brag about it.

Chris, I purchased these intakes and because of money I'll put them on until I find Air Gaps. I didn't realize who you were until Bob told me. Thanks for taking the time.
Thanks to everone else, too. I will post results of what we find...

cstraub69@comcast 04-16-2004 08:58 AM

Brian,
Don't listen to Bob, I like to under the radar. I am forturate to love what I do so that makes the job easier.
I am not here to hack anyone off either and I love the input that everyone gives. I am lucky that I have been in situations that are the "what if" sceneros and have thrown 5 different intakes at an engine to see what it would do. I can't stress enough with these marine bullets, don't get hung up on HP numbers, that is a calculated number, the torque is what is measured.
Good luck with the install.

Cobra,
The extrude hone is neat stuff but it works better on a fuel injected application. Intake surface texture needs to be rough to promote laminer flow. . .simple terms this is an undercurrent that is created right above the surface of the intake. This "air highway" helps to carry the atomized fuel/air into the bowl area of the head and to the intake valve. With a smooth surface the fuel molecules will drop from suspension at lower velocity and hamper good combustion events.

Chris
Stef's Performance

FWK 04-16-2004 10:45 AM

I used the air gap on my 468 also. As I wanted to spin my engine a little higher than the standard RPM

bryanspeedracer 04-16-2004 07:59 PM

Thanks Chris. Many people would charge for all of the advice you gave. I owe you a beer...

Bryan

blue thunder 12-24-2004 07:24 AM

Re: Big Block Chevy Intake decision
 
Diggin up bones here.... Any update on performance with the Victor Jrs Brianspeedracer?

BT

bryanspeedracer 12-24-2004 09:32 AM

Re: Big Block Chevy Intake decision
 
bt,

I have not run these motors. I ran short on time before winter came so I put them in the boat (No indoor shop). I did put Victor Jr's on with a 2" HVH spacer as my carbs are a little large (850). It's a comprimise for sure. Before I started this I wanted the boat to go like hell. Now I just want it to be reliable. I'll update in the spring when I get it out on the water.

blue thunder 12-24-2004 10:12 AM

Re: Big Block Chevy Intake decision
 
I'm going to try a set of victor jr in the spring too brianspeedracer. Right now I run edelbrock rpm performer dual planes. I think victor jr will be an improvement. I really don't care about torque under 4500rpm. I want the power coming on at 4500, not tapering off like a dual plane. Should be a good test. If I don't like them I will sell them next winter....

BT :cool:

bryanspeedracer 12-24-2004 10:25 AM

Re: Big Block Chevy Intake decision
 
bt,

What is your engine set up? I'm running 468's with GM 990 heads at 9.5 to 1 comp. Valves are 1.88/2.25. cam is an isky 114 centerline marine cam (I've forgotten the duration/lift (I'll post later). My machinist used Isky springs as well. Crane Roller Rockers. Comp Cams pushrods. Nothing exotic, probably more of a compromise between opinion, experience, and finally money.
If I had to give advice from my experience, it would to be more conservative than experimental in a build-up. I found many, many opinions on the correct set-up. I now understand why the top marine builders command themoney that they do. Lots of destructed parts. I enjoy building these things and I value the experience that comes with it (although trial and error at times...). Ultimately, I'm too short in the pockets to just write checks without learning anything other than theory...

blue thunder 12-24-2004 03:50 PM

Re: Big Block Chevy Intake decision
 
My engines are 469cid (.070 over) and running ~9.5:1 compression. Edelbrock rect port heads, as of a few minutes ago (found bad lifter) I am going to run .564/.570 278/288 111cl flat tappet cams. I was running .544/.564 .270/.278 111cl with good luck. Changing to the single plane moves the torque band up considerably on my dd2000. That is why I am thinking Victor Jr. That and the hp500s ran single plane w/ 800dp. I have better exhaust than the hp500 so I think even though I have less cid, I will be able to utilize the flow better. That is one thing about this whole thread never mentioned, exhaust. That has a significant bearing on induction selection. Dual planes constrict the free flow to 1/2 of what the single planes offer. Hopefully I don't push my torque too high. Looking to run at about 5400rpm max. With this setup my torque will peak at 4000 rpm, my hp at 5500. Peak VE between 4500rpm and 5000 rpm at 93.5% Just the way I think it should be for WOT max pumping efficiency.

BT :cool:

bryanspeedracer 12-27-2004 02:51 PM

Re: Big Block Chevy Intake decision
 
My cam specs are as follows...

Advertised. Int. Exh.
Degree 280 292
valve lift .565 .590
@ .050 232 244


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