Ram air 3 vs. ram air 4
04-26-2005, 11:01 PM
#3
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Depends on the rest of your combo, both were designed for 10.5 compression.
There are much better cams out there now for old school Pontiacs than either of those (unless you're running a 455).
There are much better cams out there now for old school Pontiacs than either of those (unless you're running a 455).
04-27-2005, 10:55 PM
#6
The edelbrock rpm heads are based on the RA IV heads and then improved on. KRE also has round port and d-port that flow better then RA IV 's with better choices in combustion chamber cc's for todays octane.
JBP is supposed to be working on reproduction RA IV heads to boot.
You can still find RA IV heads if you search around, but you will pay a premium for them, which is ridiculous since the aftermarket has stepped up to the plate with better stuff.
JBP is supposed to be working on reproduction RA IV heads to boot.
You can still find RA IV heads if you search around, but you will pay a premium for them, which is ridiculous since the aftermarket has stepped up to the plate with better stuff.
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04-28-2005, 11:17 AM
#8
Originally Posted by TA Dave
Depends on the rest of your combo, both were designed for 10.5 compression.
There are much better cams out there now for old school Pontiacs than either of those (unless you're running a 455).
There are much better cams out there now for old school Pontiacs than either of those (unless you're running a 455).
What other cams would you recommend? I too am looking at different cams for my 400 and would be interested in your input here. Here is the thread I was working from.
https://ls1tech.com/forums/pontiac-firebird-1967-2002/308624-suggestions-build-up-my-400-a.html
Thanks.
04-28-2005, 02:06 PM
#9
The HC-02 cam I had in my T/A (and that I mentioned in my previous post in the other thread) is very close to the RA-IV profile. A good buddy of mine just had this same cam installed in his original 1973 Super Duty T/A. His engine dyno is featured in this month's High Performance Pontiac magazine. I've attached the article (if you can read it). With the 100K file-size limit, it's hard to make the pages look good. If you like, I can email higher resolution versions of these scans.
Ken Crocie from HO is a good guy and his contact info is in the article. I would recommend talking to him. My buddy Richard's car is very streetable and should be breaking into the 12's with some tuning (of course it's a 455 and lighter than the later 2nd gen cars).
Ken Crocie from HO is a good guy and his contact info is in the article. I would recommend talking to him. My buddy Richard's car is very streetable and should be breaking into the 12's with some tuning (of course it's a 455 and lighter than the later 2nd gen cars).
Last edited by Glyselle; 04-28-2005 at 02:13 PM.
04-29-2005, 09:23 PM
#10
A RA IV cam in a 400 is almost too large for street use. It will have a soggy bottom end response and will idle like crap. Pontiac stuck 4.33's out back in RA IV cars.
I would use an 068 cam in the 400. Rhoads or crane fast bleeds always help with high duration cams so you may want to try that with the RA IV cam, but I wouldn't recommend it. You can always turn your 400 into a 455 and use the RA IV cam.
I would use an 068 cam in the 400. Rhoads or crane fast bleeds always help with high duration cams so you may want to try that with the RA IV cam, but I wouldn't recommend it. You can always turn your 400 into a 455 and use the RA IV cam.
05-01-2005, 12:53 AM
#11
My 400 was very streetable with the HC-02 cam, although I think the ramp was faster than the factory RA-IV profile. If I remember right, we're talking about a four-speed car. If you run the idle a bit high and tune the carb well, it should be fine, particularly if the engine has some compression. My 400 only had 8.5:1 and would be a little low on vacuum if the idle was under 850. Usually I kept the idle at about 900 or 950. Of course it didn't idle like a luxury car - it was a street/strip car and I was willing to pay the price of having a less-than-perfect idle. And the torque was great - I had a lot of trouble hooking it up! It was great for me, and also the guy who bought the car from me. He has used it as a daily driver for about two years, and just contacted me last week to see if I have any more cars for sale, since he liked that one so much!
Sure, the RA-III will have a smoother idle, and if you want to make about 300 horsepower, it'll get you there. But if you want a 400 engine that will get you into the 13's in a 2nd-gen car, you're going to have trouble with the RA-III cam. An HC-02 cam and ported 2.11/1.77 heads should make over 400 horsepower. At least they did for me.
Sure, the RA-III will have a smoother idle, and if you want to make about 300 horsepower, it'll get you there. But if you want a 400 engine that will get you into the 13's in a 2nd-gen car, you're going to have trouble with the RA-III cam. An HC-02 cam and ported 2.11/1.77 heads should make over 400 horsepower. At least they did for me.
05-06-2005, 01:26 PM
#12
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Yea that would be good my email is FirebirdLTA@aol.com...if he has any 400, 428 or 455 block for a reasonable price thats would help me even more
Originally Posted by Glyselle
The HC-02 cam I had in my T/A (and that I mentioned in my previous post in the other thread) is very close to the RA-IV profile. A good buddy of mine just had this same cam installed in his original 1973 Super Duty T/A. His engine dyno is featured in this month's High Performance Pontiac magazine. I've attached the article (if you can read it). With the 100K file-size limit, it's hard to make the pages look good. If you like, I can email higher resolution versions of these scans.
Ken Crocie from HO is a good guy and his contact info is in the article. I would recommend talking to him. My buddy Richard's car is very streetable and should be breaking into the 12's with some tuning (of course it's a 455 and lighter than the later 2nd gen cars).
Ken Crocie from HO is a good guy and his contact info is in the article. I would recommend talking to him. My buddy Richard's car is very streetable and should be breaking into the 12's with some tuning (of course it's a 455 and lighter than the later 2nd gen cars).
