hey folks so I have a 69 400 with a muncie 4sp current set up is #62 heads iron intake pretty much stock set up with HEI holley 4150 - 650cfm I am looking at either the performer or the performer RPM Engine runs decent no knocks pings or oil burn except a little at start up I really want a better performance between 1500 and 5500 right now it seems to really start to run well at 4500 RPM so its a short curve for lack of better term I need more torque and HP all a round
question is with out getting into the lower end would you recommend the performer or the performer RPM I would like it to possibly be a roller set up but main thing is I dont want to push it to hard and wind up with a blown motor since im not really ready to get into the lower end Thanks alot for your input ![img]https://firstgenfirebird.org/forums/ubbthreads.php/ubb/download/Number/19810/filename/69bird.jpg[/img]
If it don't make power til 4500 rpm, sounds like your cam may be too big.
So what are your cam specs ?
If having too much cam is your problem, maybe a smaller cam will bring your power band back down where you want it.
Another thing that can reduce low end power is having a slow timing curve, & one that doesn't begin to come in at low rpm. Most seem to agree that the advance springs & weights should be adjusted to where they begin to advance the timing just above 1000rpm, & apply full advance at just below 3000 rpm.
Many HEI's have stiff advance springs that don't start advancing at a low enuff rpm, & don't reach full advance 'til after 4000 rpm. You can probably see how that could put your power band up closer to that 4500 rpm you mentioned.
So, have you ever checked your timing curve ? Do you know what it is, now ?
I'd also recommend a GOOD, properly rebuilt & functioning Q-jet carb, rather than that 650 Holley. You mentioned an iron intake. What type adapter are you running under that Holley, to mate it to the spread bore iron intake ?
The Performer will make power mostly from idle to 4500 or so.
The RPM is more for mid-range & higher rpm.
The factory iron intake is supposed be the best of the 3, all-around.
If I understand your post, you are asking about a set of alum heads, intake, & possibly a roller cam. Is that correct ?
My advice is to determine exactly what you have now. A new timing curve and/or a different cam MAY provide the power you seek, and save you lots of money.
MOST guys don't recommend putting new top end parts on a well used bottom end.
But, if you are gonna do it anyhow, I'd go with the smallest cfm D-port alum heads. You don't need the big cfm flow. It will reduce low rpm torque & power.
Also, which ever type cam you decide to go with, stay on the smaller, or more conservative side. It don't take a big cam to make 1500-5500rpm power in a Pontiac 400. If your car will be mostly street driven, you want more low rpm torque & mid-range power, rather than power above 5000 rpm, where you don't go very often.
If you don't wanna bolt an iron intake up to the alum heads, you could buy a factory alum Q-jet intake, like used on the RAIV & 455HO engines. There have been aftermarket copies of these on the market for a few years. If you decide to do this, be advised that some of these intakes have been found to have ports that didn't match up well with the intake ports in the heads. Some needed some port matching work, before use.
Nothing wrong with the performer RPM We ran 12.07 @ 119 mph with a .030 over 400 with stock unported heads with a factory ram air 3 cam and a 850 Holley Its all in the tuning If you really want to go fast ditch the iron intake. Low RPM power and cfm is nothing but internet mythology A Modern 5.3 LS has better heads than any aftermarket pontiac heads and a tiny 5.3L can move a 5000 lb truck pretty [censored] good. Most likely blow the doors off any 3500 lb Firebird with a 326 or 350 prove me wrong
"...If you really want to go fast ditch the iron intake..."
Sorry, but that don't make any sense, at all.
There are several Stock Elim Pontiacs that have run mid to low 10's, running a legal iron Q-jet intake, with a legal 750cfm Q-jet carb. I can list driver names & post pics of the cars, if need be.
"...If you really want to go fast ditch the iron intake..."
Sorry, but that don't make any sense, at all.
There are several Stock Elim Pontiacs that have run mid to low 10's, running a legal iron Q-jet intake, with a legal 750cfm Q-jet carb. I can list driver names & post pics of the cars, if need be.
Go ahead, prove me wrong !
how many engines have you ever built? what do you know about stock eliminator? how many years have you drag raced?
i will meet you anywhere with a 400 cubic inch pontiac and $50,000 and run anything you can bring. prove me wrong
How did this thread devolve into a D### swinging contest? No wonder the op never responded back. Save that crap for that cesspool called Facebook. Rant over, Merry Christmas guys.
How did this thread devolve into a D### swinging contest? No wonder the op never responded back. Save that crap for that cesspool called Facebook. Rant over, Merry Christmas guys.
and to answer the OP original question. This is along the lines of intake system you will need if you want to go fast. The old mythology will only get you so far, which is slow.
If you do not want to rev the engine past 4500-5000 rpm a RPM intake is just spending $$$ for performance at a RPM range you will not push the engine to. A regular performer's only real advantage over a stock 67-72 Pontiac iron intake is weight. I would not spend my money on an intake with what you plan on doing with the car. Just my 2 cents.
Keep on repeating the same old drool about RPM and quadrarets iron intakes that you read from some ancient garbage you read from 30 years ago that you have no first hand experience. PM and other clowns made $$$$ Off a bunch of B.S. AND you eat it up. A 5.3 ls will eat any Pontiac up