I currently have a 69 428 in a 65 GTO. It is a YH code 4 bolt main that has been bored 30 over. It has a cast crank, probably the original looking at the casting number, heat treated rods out of a 62 421SD, and TRW forged pistons. It has 72cc Edelbrock Performer RPM heads and an Ultradyne 280/288 H12 cam with a lobe separation of 110 degrees, 223/231 duration @ 50 and .463/.485 lift with 1.5 rockers; however, the engine has 1.65 rockers so the lift is .510/.534. Currently it has an Edelbrock P4B square bore intake (the older style with the smaller runners) and an Edelbrock Thunder AVS 800 carburetor. I am considering replacing the intake but I cannot make up my mind between the Edelbrock Performer and the Edelbrock Performer RPM. This car is not for the track and most of its use will be weekend cruises, car shows, and maybe a couple of cross country muscle car tours, hopefully. Oh, and the occasional full throttle stop light romp, we must play every now and then and my brother-in-law has a 71 454 SS Chevelle that I love to embarrass. The cam's RPM is rated from 1500 to 5800, or 2000 to 6500 depending on which web site you look at. I know the Performer intake is for low end power and is rated from idle to 5500 while the RPM is rated from 1500 to 6500. Would I be better staying with the P4B intake, getting the Performer intake to match the type of driving this engine will see most of the time, or getting the RPM intake which is a better match for the cam's operating RPM? When you drive the car you can really feel when the cam starts to become effective. Around 1700 the car has a lot more power. It is no slouch below 1700 but it is definitely stronger above 1700. One person advised to use the Performer Intake with a 1" closed spacer so you have the low end power of the Performer but the spacer would help add some high end power to better match the cam.
I know just enough about this stuff to make myself dangerous, but not enough to be able to make great decisions that won't result in wasted money. So any help or advice from the experts out there would be greatly appreciated.
Someday, money permitting, I would love to put a tri-power setup on this car. But that option is cost prohibited as of this time.
I'm guessing you run an automatic, I would recomend a small stall convertor to get you up to your cam easier. Nothing is gonna work "better" than the factory intake and quadrajet below 1500 rpm.
If it was mine, my first choice would be a rebuilt/refurbished 1966 tripower unit. My second choice would be a '68-'72 factory Q-jet intake with a good 800cfm Q-jet. Both are far superior to the Edelbrock stuff in every way.
I would buy a 66 Tripower if I had the money so I could get one that is rebuilt and ready to go. I am trying to make what came on the car work the best it can without spending too much money. If I had an original intake and Q-jet laying around for a 69 428 engine I would probably restore it and put it on, but it did not come with the car. That is why my question was which Edelbrock intake would work best with the combination I have.
I also know that you can't make a cam work 100% below its operating range, but some combinations will make it better, some will make it worse. My question was not how to make it work below 1500; it was which intake would be better.
Here is the original question again.
"Would I be better staying with the P4B intake, getting the Performer intake to match the type of driving this engine will see most of the time, or getting the RPM intake which is a better match for the cam's operating RPM?"
As I said, some day in the future I hope to be able to add a tripower, but for now I need to make what I have work as good as I can.
Thanks for any advice which will help me pick a decent intake for my engine combination.
Dale
Well put, Dale. That said, you might try the performance years forum regarding your choice of intakes. There is much information there on aftermarket parts. I myself am no authority on Edelbrock flow characteristics. Other forum members here might well be and be able to give you some sound advice. I did not mean to "shoot you down" or burst your bubble, and if I offended you, I apologize. I simply didn't read the question thoroughly and cranked out a quick response. Good luck with your endeavors.
I had a Holley street Dominator intake and after some research it became obvious that the factory intakes were hands down the best for the street........ I bought a stock cast iron intake on ebay. For your purpose I believe the stocker would perform best, that said I do not believe you are losing much with the pb4 you have, and probably not worth switching with another aftermarket intake. my $0.02
Well put, Dale. That said, you might try the performance years forum regarding your choice of intakes. There is much information there on aftermarket parts. I myself am no authority on Edelbrock flow characteristics. Other forum members here might well be and be able to give you some sound advice. I did not mean to "shoot you down" or burst your bubble, and if I offended you, I apologize. I simply didn't read the question thoroughly and cranked out a quick response. Good luck with your endeavors.
You did not insult me or shoot me down. I just figured my question got lost in the long explanation. Thanks for responding with your advice and experience. I hope you have a Merry Christmas.
Dale
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