My combo is a 306 with afr 165 with a custom cam (550/560), 70mm tb, 75maf, 30# injectors, 3.73's, TKO tranny, 1 3/4 longtubes. What intake do you guys recommend?? The RPM or the RPMII?? Also what kind of fuel pressure do you recommend I start with??? It was running rich at 35#'s!!!! Thanks in advance
RPM or RPMII ?????
- Thread starter Bad Animal
- Start date
Mike86Stang
Advanced Member
The standard RPM would be a better match to the 165's. I'm just curious as to why you went as big as 1 3/4 with your longtubes though. A set of 1 5/8 would have been better for street use with the amount of air the heads and intake would flow. On the other hand, if you're wanting to see some RPM with the combo, I would suggest the RPM II, but would question why you limited your head selection to your use of 165's instead of the 185's?
the 185's and 165's share the same exhaust ports. I don't care about street use!! I felt the 185's would be major overkill on a 306. And a 1 5/8 inch header won't even cover the exhaust port on these heads!! THe 165's are producing as much a 500 hp with a naturally aspirated combo. The motor will be shifted at approximately 6500 RPM.
hmm
my 1 5/8s work just fine on my 165's
back to your question, what rpm is the cam gonna peak at?
that will decide which intake
my 1 5/8s work just fine on my 165's
back to your question, what rpm is the cam gonna peak at?
that will decide which intake
Well, considering the engine is to be run to 6500rpm, and low end, off-idle torque isn't a concern, the RPM II should be the intake of choice, but the 185's would still have been a better head choice to accompany it, IMO. The 165's are an excellent street head and designed to breathe well from the idle-6000rpm, but will rapidly take a downward spiral soon after that. The 185's are designed to run from the 1500-6500rpm margin where you seem to be planning on spending most of your time and would still be a better choice, regardless of the engines 306 displacement. If high RPM's are what you're looking for, I'd consider have the 165's ported. If not, then stick with the Regular RPM intake and concentrate on a cam selection that's going to give you a better bang within the idle-6000rpm parameters and stick with a set of 1 5/8 headers. You could run the big intake with the 165’s, and 1 3/4, but you’ll definitely be leaving some power on the table at both ends and might find yourself with less than dramatic low end and a not quite capable top end.Bad Animal said:
88GTStreetRod
Member
I just installed the RPMII intake with the Performer RPM heads. Man.... What a difference. The car as a lot more punch above 4,000. I think I lost a little on the bottom end, but I ended up putting 4.10 gears in and that solved my concerns. I would go with the RPMII with your set up and set the fuel at 38lbs. I gained 96 HP by adding the heads and intake. I had to also clock my mass air metter 90 degress so that the sensor would pick up the much larger amount of air being pulled in throuh the cold air intake.
Bad Animal said:
Black331Stang
Active Member
i dont ssee the big fuss here 
its a 306....the 185 would be kinda overkill with that setup. its just a basic bolt on setup. gonn ahve to know what range the cam is good in. But im still gonna say just go with teh RPM.
its a 306....the 185 would be kinda overkill with that setup. its just a basic bolt on setup. gonn ahve to know what range the cam is good in. But im still gonna say just go with teh RPM.
I think the RPM II is designed to compete with the Holley Systemax II intake and the TFS Track heat R sereis intakes. AFR recomends the RPM for thier heads.
Black331Stang
Active Member
yeah the RPM matches well.....and i think the RPM can handle up to alot more than that. Even ford says the Cobra was rated to 400 HP lol pffftt right. (NA) ive seen dynos of RPM IIs make 17-20 more HP in the 400+ range.
Bad Animal said:
i dont think thats a custom grind. its favoring the exhaust any custom cam designer would not favor the exhaust on a set of afrs they need no help on the exhaust side. You better start by sending that back and getting your money back. i honestly dont think anyone can give you an accurate intake selection without the duration of the cam rather the lift. Whats this car going to see more, Track or Street?
runningmole
Founding Member
8urlt1 said:
My cam favors exhaust. Custom from Ed Curtis, and I'm using AFR 185s....
What intake did you have listed when the cam was specced out? You should use that. If not, I think you'll do plenty fine w/ the RPM (old style)
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