anyway, I had fuel and idle and running issues lately, and after I got everything seemingly sorted and adjusted I finally found the main problem, intake vacuum leak. I had been planning on getting a new intake anyway, so Im not too bummed about this.
I am most likely going with an edelbrock performer rpm. from tests done between intakes on the hot rod magazine shootout, and the fact that I want to keep a dual plane, this one tests best. that and if Im going to replace the intake, I dont want to put something that wont really make the time and money worth it, ie: dp48 or regular performer, etc. However, I know it sits taller than stock style stuff so my question is this:
does anyone know the height for this intake? edelbrocks page only has victor and super victor heights listed for BB chryslers... I currently have the stock 383 hp 4 bbl iron intake, with a 1 inch plenum spacer and my holley 750. I have a 2 inch tall air cleaner, so I could fit the 1 inch spacer in there. do you guys think that without any spacers, just going 2 inch air cleaner to holley 750 to performer rpm to heads, I should have enough clearance?
ok well Im using ebay info and hoping it is accurate
performer rpm is 5.8 inches tall
the regular performer aluminum intake is 4.35 inches tall, so I am going to use that as a model for mine. Ive got an inch tall spacer so thatll make is effectively 5.35 inches tall, and I have 1 inch of headroom above my air cleaner, according to slamming the hood on an extendable magnet stick.
so that should technically leave me .55 inches of extra room with the perf rpm in there... give or take a quarter inch for error and bad eyes with headroom, I think it should just fit under there.
seems basic, if anyone sees a flaw please yell at me.
Joined: Wed Nov 17 2010, 03:28PM
Location: florida
Posts: 1311
I would be more concerned with the 2" air cleaner height.they make deep drop bases so maybe you can go to a 3" element.the spacer could be eliminated in favor of gaining height also.without enough airflow the added plenum height might be negated anyways.your new manifold choice may not like the extra height of the spacer.
my current element is 14 inches wide and 2 inches tall. Since I have 2.5 inch dual pipes, but still non HP manifolds, im bored over .030, I have a 750 four barrel holley, and hypothetically, an eddy performer rpm, I will adjust the typical peak 383hp rpm from 5500 to 5800rpm... neither of which I will probably ever see much if any.
Area = (C.I.D. x RPM) / 25,500 Area = (389 x 5800) / 25,500 effective filtering area - 88.478
Height = A / (D x 3.14) Height = 88.478 / (14 x 3.14)
Height, with 14 inch diameter, is 2.012.
I think I should be sitting pretty with a 2 x 14 filter (plus rubber seals, which can account for the .012, for the mathematicians) regardless of whatever semi mild changes I make to it.
Joined: Wed Nov 17 2010, 03:28PM
Location: florida
Posts: 1311
Math is great but sometimes due to hood clearance issues a short element get used and the lid is down close to top of carb which can create flow restrictions.make sure you have enough clearance under the lid not just under hood
very possible. the way they worded it and worked out their 454 seems to me they threw out that part of the equation for some reason. I hear what you are saying though. we will see how she rolls with a different intake. maybe ill rig up some nascar air induction too. and then get stuck putting my 9 psi pump back on. circle of life...
Joined: Thu Mar 22 2007, 08:13AM
Location: In the workshop
Posts: 1063
Edelbrock state on their website that the carb pad height of an RPM is 5.35". They use a simple formula which is A+B/2 to arrive at this.
As regards drop base cleaners. a lot depends on which carb is being used. If its an Edelbrock electric choke, then it cant be to low because it fouls the mechanism. Whichever way, a banjo type fuel fitting will probably be needed. If its a Holley carb, then the choke horn fouls...
Remember also that when a drop base is used, the air cleaner top gets closer to the carbs top, possibly creating an air flow restriction...which is then eliminated by using a taller filter, and loosing cleaner/hood clearance. Catch 22!
we'll see when it all goes together. I ordered a performer rpm and the intake gasket set from felpro with the valley pan and 2 sets of the paper filters. the 2 inch element might be ok, we shall see.
I have a 750 holley with no choke being used.... dont necessarily want to remove it though.... id probably lose it all.
I dont expect its going to set the world on fire, just lighten it up and help it breathe more. I still have 516 heads and stock manifolds, so its not going to be breathing fire.
if it really boils down to needing more air, I can look into some low rise dual plenum nascar-ish setups, maybe remove my high beams and make it look mean. hopefully the stock carter pump will keep up with it. I assume it should do fine.