I had my mind setup and I have the intake manifold already but being that I am to the stage of assembly I am now starting to second guess my decision on the intake manifold for my application.

The engine I am building is a 306 displacement 302 with a Crane roller cam 1,400 - 5,400 power band with a 6,000 rpm valve float. 302H Hydraulic rollers are going to be used with improved valving for stable operation to 6,500 rpm.

Intake I have currently is an Edelbrock Performer #2121 also known as Performer 289 which is listed as idle to 5,500 rpm. I also have a 1" plastic phenolic spacer and thick 4V insulating gasket to go between my 800cfm Sniper Stealth and manifold.

I am hearing how ever since I have AFR 165 Renegade heads that I should go with the Performer RPM even though its 1,500 to 6,500 it will still have the same low end power as the #2121 which is basically a stock OE manifold as I keep getting told. Im starting to become a bit worried with so many naysayers that this intake might be too small for the heads I have. This isnt a all out race engine nor is it a street/strip engine, I am building it for low and mid range power for my truck which I drive daily between 1,500 and 3,000 rpm depending on city or highway driving. Many are saying this intake will fall on its face at 5,000 as well.

So what does everyone think? Is the Performer going to be a hinderance or will it be a good intake for a daily driver with the upgrades I have?

Big reason I went with the 2121 is cause it has a raised pad I can drill and tap for an extra temp sensor for my Sniper Stealth. The Performer RPM or even the RPM Stealth I am afraid might be too tall to properly work with OE throttle cable let alone the kick down rod for my C6 as well as the lack of a boss to drill and tap for a temp sensor. There is also the issue with vacuum ports positioned where the throttle bracket adapter plate goes which would make the OE vacuum tree nearly useless. For me the 2121 has everything I need but I feel like I am going to be choking this engine down and it wont like having the 2121 intake with the rest of the package. Only flow data I could find on the intakes list the 2121 as 205 cfm per runner and my heads are 251cfm @ 0.500" and 255cfm @ 0.550". Cam I have is 0.520"/0.542" lift but the 205 number has no information on what the flow was done at to even attempt to make a comparison.

Yes I understand I may be over thinking this but with how much money I got in this build to be a long term engine in my truck I want to make sure it is right and I dont have to go back making changes here and there.

 

Look into Big Dogs Porting on Facebook. I bet he can get that manifold to flow over 250 CFM.

 

If that's all you're shooting for then use the Performer. The RPM improves the topend only and that with a carb. Never tried one with an EFI system.

 

You have the correct intake for this application IMO.

It may well... but why do you care.

 

I care cause the cam is listed as having a 1,400 - 5,400 powerband and I am going to have Broader Performance tweak the governor on my C6 to shift at 5,500 rpm at wide open throttle. At least that was the plan.

 

I havent either. I guess I will just have to try the plain performer and see how it does. I tried finding another intake and couldnt find anything I liked. Hopefully with the EFI there wont be a loss of power above 5,000. Hopefully the people that experience that is from running OE stock heads or have a improperly sized carb or something.