http://forums.corvetteforum.com/zerothread?id=848092

Rather than retype. Engine size is set, my concerns are with the cam. Choosing smaller cubes means more radical cams so I know it's a trade off but will this one be driveable? The DD plot makes me believe this motor setup with the fairly flat torque curve would be a good driver with a nice lopey idle. DD may not be totally accurate but does follow the edelbrock curve for basiclly the same motor they built. Comments? Vacuume issues?

 

If you could make a custom EFI setup using the Performer RPM, then more power to ya Let us know how it goes.

 

That part about the converted dual plane has been bouncin in my head a while now. Obvious reasons given our EFI choices, don't need to preech to the choir here. The only problem I see here is that the dual planes runners, where they mate to the head, the outer casting is not level. This creates a problem I can't seem to come up with a good solution for. You could weld in the injector bungs at diff't depths into the runners, but then you have one 4 well placed injectors and 4 that are too high or too low.

What are your thoughts on that? Any other problems you foresee? A Performer RPM would fit my powerband well.

[EDIT] I just looked at your cam specs, I am by no means an expert, but based on what most mfr's recommend that is too much duration for the compression. If that's a close copy of an edelbrock engine I would be that you won't find them recommending one of their own cams with 300* adv. for a 9.5:1 motor. Make sure you look into this, nothing worse than being disappointed when it's all over.


[Modified by RainDelay, 1:24 AM 6/30/2004]

 

That is one of there cams that I listed, If you go to the edelbrock site and click on intake manifolds and go to the performer rpm intake you'll see the dyno graph and a link to a motor they built. I realize an efi motor may be slightly different than a carb motor and may require something slightly different that's why i'm asking for comments. I certainly won't lay claim to the design just happened to come across that and it sure seemed to fit the bill for me. I've already got the intake and i'm ready to tig the bungs in with the tig welder, just need to find time to do it and still need to pull the motor to see what it looks like. The bungs will be level with one another but because of the build nature of a duel plane they will look a little off because of one runner being lower but they will be level at the top so all injectors sit where they are supposed to. I'll certainly take pics and I haven't made the plunum yet but it will fit with no hood issues and will be using the stock throttle body. I have a couple details but it's gonna fit. Thanks for the comments so far, keep em coming. I may also email edelbrock and tell them what i'm doing, they've actually been pretty helpfull in the past.

edelbrock heads or dart pro 1 ??


Thanks.

 

Yeah, I'm certainly not going to say that cam won't work, it just seems like alot when compared to the suggestions at other mfr's sites. I personally can't argue with Edelbrock.

One other question on the dual plane, how will you mate the TB to the intake? Box plenum style or 90* elbow style? I don't know squat about airflow to argue for or against either (just that the air has to 90* at some point no matter what anybody does) I'm just curious. As I said before, I've been tossing around the dual plane idea myself and have some unanswered questions.

About the heads, I did notice when researching for my heads that Edelbrock, out of the box seemed to have the lowest flow per runner size. That is my out of the box AFR 210's beat Edelbrock 215's (victor series) hands down. My guess is Dart would also.

 

The machine shop here who does alot of 7 sec. race motors really like the dart's. I was originally looking at trickflow but he convinced me otherwise and showed me a set of dart pro 1's and they look like a quality piece. I believe the edelbrocks are 170cc and the dart's i'm looking at are 200cc. I assume that's the sole reason desktop dyno gives me better numbers than what edelbrock posted. I'm certainly concerned about the cam choice (still have a few weeks before it gets torn down) so hopefully others will chime in. I assume if edelbrock shows a "dyno proven setup" and it falls short alot of people are gonna know about it and it would be easy to find that out, to date I have not found anything like that.

I'm still throwing around ideas for the plenum, I am heavily leaning towards smoothing out the flow into the intake and steering away from a "box". If I was going forced induction (which I certainly thought about) the box type plenum would certainly be out of the question. I will never claim to be any type of expert regarding that but I'm not aware of any box type plenums on any new motor today anymore. It's not going to be a 90 degree elbo because that alone won't put the throttle body where i want it (stock location) but somewhere between the two styles. I'm also going to build my own headers so i'm a glutton for punishment

 

You can individually plumb the injectors... MSD and several other companies (BDS, The Turbo Shop, etc) make bungs that are internally threaded. You then thread the injector body and screw them into the bungs which negates the need to them to be held down (like the rail does when it's bolted down). They also make special feed lines that plumb into the tops of the injectors and usually use hardline (kinda like a direct port N2O system). I've used these setups quite a bit with old Enderle setup and calliope stacks, as well as plumbing roots blowers for EFI use.
-Jeb

 

I've seen those but I've already got everything in my garage collecting dust. What's your take on the cam Jeb?

 

I personally think it's a little bit large for a street engine with 9.5:1 compression and 350 cubes (or just slightly more). The lsa helps, and the lift isn't too high but the duration is pretty long. You may have some overlap issues. I would personally go with a cam that's a little milder; don't just pick a grind, use your heads' flow to determine what you need.
-Jeb

 

Thanks, I'm still learning as far as cams go.