I am building a fairly hot 390 for my f100 like 10.5:1 CR 280 comp cam and 1.75" tube headers. But my dilema is should I go S code cast intake or Edelbrock performer RPM . Is there much performance difference between the 2, weight is of no concern to me. cast intake for $100 bucks or edelbrock for $475 worth the extra money???

 

Are you going to be doing some port work to cast heads or going after market? Because your going to need to get the intake to work in conjuction with the cam and the heads......A good intake with crappy heads is just that.. the cam wont let either end breath...

RJ

 

Yes the heads will be ported and polished

 

What heads were you planning on useing...... well at the least, your going to have to port the S intake to match the port work in the heads.... and with the RPM intake you'll probably just have to tootsie roll to match the heads alot less work.....JMO

But being less weight and a better design by far....the RPM for FE's is a hard intake to beat....from off idle to 6000rpm's.....

 

Russ expand on the method used to port match the intake to heads would you ? I recall reading a thread a while back 2+years ago..something to do with carbon paper or ? then again...CRS & dislexia are a horrible combo

 

The way I port matched my 302 intake and heads was placing the gaskets ligned up very well using the bolt holes for alignment. Then I took a pick and scored the intake or heads transfering the outline of the gasket on to the metal. I also used a red sharpie marker to color the metal to be removed. Then just remove all the material that is colored and now the ports are matched to the gasket opening and the coresponding part. You also want to feather out the transition from the material removed into the runners. Any buddy have a better method?

 

If you're shooting for the build you listed, why throttle it with an "S" code intake ? A new RPM intake isn't the only choice out there. Blue Thunder makes a good copy of the 428PI/427MR intakes, plus the originals are still out there to be had. Then there's the iron 428CJ intake too.

 

Well Bob, I'll try to tell you how I do it..with this freakin Hangover....LOL... (the Truth tho)

With the heads all ready being ported... and as mentioned above...I lay the Intake head gasket down on the head...and run a couple short bolts and flat washers into it...Just finger snug as not to move.... Then with the intake valve's (out) I spray Dykem into the chambers toward the port..making a transfer..... to the gasket..

Then I pull the gasket......and with a sharp utility knife cut out the witness mark area.. on a flat surface... Then I transfer the gasket over to that side of the intake...and I'll use some shorts bolts and the same washers..with nuts on the back to hold it in place.....and spray the Dykem on the gasket at the port location's.....and use a scribe to mark those lines.... But dont be to rough around the gasket with the scribe....

And I go a little further than some may do.... I'll bolt the head and the intake together.....and re-spray again both thru the Chamber and thru the Intake and double check any witness marks...

 

Well not too split hairs on intakes... BD... But go to Net54 and look up Jay Browns the Great Intake Comparo..... and read the results... this is old news.....everyone was expecting the BT to do well... and the RPM somked it....on a semi built 428...

And G, If you read this..correct me if I'am wrong... Still have the Hangover!! LOL

RJ

 

To me, Jay's testing was good on only the build he used it on. Too many other variables here that otherwise could change the results on other builds. And he didn't port match the intakes either.(except for maybe one that I recall) Carb tuning was as well minimal, I don't recall them playing with that aspect either. The RPM has really small ports. Can't say for how well the BT intake matches up to the heads he used. The stock Ford intakes have a better port match than the RPM does.

 

Would you run the stock iron 4bbl intake on a mildly built 390?

 

Ummm....

You might want to re-read the "finals" in Jay's manifold contest. The Blue Thunder was not "whomped" - it was the winner in both horsepower and torque. The Performer RPM was a close second. Both intakes out performed the factory parts by a wide margin. The BT is the right pick for a Mustang or Cobra where an original appearance is important. The RPM is the right pick for power per dollar - and the best match for what you are trying to accomplish.

 

I must do things bss aackwards then and all wrong, this is what I do:
With the heads mounted on the block snug with used head gaskets (same as will be final assembly), I'll install the intake with with shim stock strips matching the compressed intake gasket (and final assembly) thickness on both sides.
Make a note of the step if any between the head and intake at the front and rear VC surfaces left and right head plus up front the step difference between the intake and head going front to rear both heads.
Start with one head on the workbench and spray machinist blue on the head and intake, bolt together at the above measurement notes and scribe head and intake. Same on the other side of the intake and head. Have at it with the porting tools then drum sand.
I had to mill a few bolt holes a little and elongate to allow the intake to compress the gasket without hanging up on the bolts and this was with the VC rails level with the heads and intake.
This way the intake and head ports will align after final assembly as they were measured and ported during mockup, perfect.

Russ, I can not find the camera card that had many photos of the C4G heads and port work plus the F427 intake I installed many months ago. I'll take some more later as the heads will come off again as the steel shim head gaskets are starting to leak combustion into the coolant. Strange as it took 7,800 miles to start leaking.

 

Well Carl.....there's allways more than one way to skin a cat....LOL.. just as long as you get the same end result... Thats why I wrote in my statement (Hangover) lol...

I probably left a step or 2 out and added a step or 2 that didnt need to be there? I havent went back up to re-read what I wrote.... I was trying to think of the average guy doing it in his garage without any machinery....

But If I was back in my shop...there would be many other ways of doing it..and getting the tolerances closer also..... Damn Bud (I cant do it all) LOL..

RJ

 

Did I read somewhere that the Edlebrock Performer is modeled after the S intake?

John