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#1
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Performer rpm apps?
Anyone ran one with a hyd flat tappet 400 ci? Thinking of using one since have one on shelf. 230 cfm 13 heads, ra iv cam advanced, 9.5 comp
….I know not the best application of parts, just using stuff already have for a budget build. I have a stock intake but don’t want to choke the heads.
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1963 Cat SD Clone (old school) streeter 1964 GTO post coupe, tripower, 4speed (build) 1965 GTO 389 tripower, 4 speed, driver 1966 GTO dragcar 1966 GTO Ragtop 1969 Tempest ET clone street/strip 1969 GTO Judge RA lll, auto 1969 GTO limelight Conv. 4speed go and show (sold) 1970 GP SSJ 1970 GTO barn find..TLB…390 horse?….yeh, 390 1972 GTO 455 HO, 4 speed, (build) 1973 Grand Safari wagon, 700hp stoplight sleeper 525ci DCI & 609ci LM V head builds Last edited by J.C.you; 09-21-2023 at 09:03 PM. |
#2
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For what you are doing the only thing gained from changing to an RPM intake is taking about 27 pounds off the front of the car. You may even loose some power if the taller intake requires a drop base air cleaner moving the air cleaner lid closer to the carburetor.
So no, at your power level the RPM intake really isn't worth the effort......IMHO....
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
The Following 2 Users Say Thank You to Cliff R For This Useful Post: | ||
#3
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Cliff, you are right, be a 70 GTO so have some hood clearance. Have you done any spacer testing on the rpm?
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1963 Cat SD Clone (old school) streeter 1964 GTO post coupe, tripower, 4speed (build) 1965 GTO 389 tripower, 4 speed, driver 1966 GTO dragcar 1966 GTO Ragtop 1969 Tempest ET clone street/strip 1969 GTO Judge RA lll, auto 1969 GTO limelight Conv. 4speed go and show (sold) 1970 GP SSJ 1970 GTO barn find..TLB…390 horse?….yeh, 390 1972 GTO 455 HO, 4 speed, (build) 1973 Grand Safari wagon, 700hp stoplight sleeper 525ci DCI & 609ci LM V head builds |
#4
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We ran rpm on 400 with ported 62 heads, runs good
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#5
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My son's car with the 400 has had the RPM for many years. We went through a series of flat tappet hydraulic cams with the last being the XE284. Always used a 1" spacer and 4" air box. Had to go to a cowl hood to get the needed clearance. Heads, #64, ported to 250 on the intake side and c.r. at 9.7 to 1. This combo yielded a best of 11.69 at 115 on 93 octane. As Cliff pointed out your combo may not benefit from the RPM but it is an excellent intake for the 400.
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69 Bird w/1970 400 block(409 cubes), #64 heads, hyd. roller, Q-jet by Jeff E., original interior, ps, pdb, th350, and 3.73 gears. Pump gas, street driven muscle. 3800 lbs. race weight. Best, 11.39 @118, my son's car. 79 T/A w/463, Scat crank, Eagle rods, Icon pistons, Lunati solid roller, 262/270, KRE 325 heads, Northwind intake, QF950 carb, full interior, ps, pdb, th350, and 3.73 gears. Pump gas, 3650 lbs. race weight. 10.68 @ 126 so far... no tuning yet. |
The Following User Says Thank You to prostreet64 For This Useful Post: | ||
#6
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Quote:
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1963 Cat SD Clone (old school) streeter 1964 GTO post coupe, tripower, 4speed (build) 1965 GTO 389 tripower, 4 speed, driver 1966 GTO dragcar 1966 GTO Ragtop 1969 Tempest ET clone street/strip 1969 GTO Judge RA lll, auto 1969 GTO limelight Conv. 4speed go and show (sold) 1970 GP SSJ 1970 GTO barn find..TLB…390 horse?….yeh, 390 1972 GTO 455 HO, 4 speed, (build) 1973 Grand Safari wagon, 700hp stoplight sleeper 525ci DCI & 609ci LM V head builds |
#7
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The only Pontiac I've played with the RPM intake on was 455's. Had one on the dyno and played with spacers. It liked a 1" open the best but wasn't huge gains. If I remember right it picked up 7 or 8 hp. The 4 hole spacer we tried lost power, just didn't like it for what ever reason. I think one possible reason is because the Pontiac version of these RPM intakes don't have the divider cut down like other engine brands do with the same intake.
Either way, it may not apply, not sure how a 400 might react differently. Easy to swap around though and experiment if you have the time. |
#8
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I think the RPM will work good on a 400 with 230 cfm heads. The carburetor choice will have an affect on spacer choice.
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#9
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Quote:
The engine seemed to like it. I was afraid to actually cut the RPM so I cut a spacer up. |
#10
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With our combo the car picked up a tenth with the 1" spacer. We used the Jim Hand design to modify an open spacer where the spacer separates the primaries but is open across the secondaries.
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69 Bird w/1970 400 block(409 cubes), #64 heads, hyd. roller, Q-jet by Jeff E., original interior, ps, pdb, th350, and 3.73 gears. Pump gas, street driven muscle. 3800 lbs. race weight. Best, 11.39 @118, my son's car. 79 T/A w/463, Scat crank, Eagle rods, Icon pistons, Lunati solid roller, 262/270, KRE 325 heads, Northwind intake, QF950 carb, full interior, ps, pdb, th350, and 3.73 gears. Pump gas, 3650 lbs. race weight. 10.68 @ 126 so far... no tuning yet. |
#11
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Nice gain!
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1963 Cat SD Clone (old school) streeter 1964 GTO post coupe, tripower, 4speed (build) 1965 GTO 389 tripower, 4 speed, driver 1966 GTO dragcar 1966 GTO Ragtop 1969 Tempest ET clone street/strip 1969 GTO Judge RA lll, auto 1969 GTO limelight Conv. 4speed go and show (sold) 1970 GP SSJ 1970 GTO barn find..TLB…390 horse?….yeh, 390 1972 GTO 455 HO, 4 speed, (build) 1973 Grand Safari wagon, 700hp stoplight sleeper 525ci DCI & 609ci LM V head builds |
#12
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Maybe consider an early Edlebrock large runner P4B QJ. I have been running one on my 67' GP 400 with great results. Rocky Rotella reported better flow then stock intake A good alterative if you don't want the height of an RPM. Jeff
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Carburetor building & modification services Servicing the Pontiac community over 25 years |
#13
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is there an intake manifold on the engine right now? if not, the rpm will be easier to carry across the shop to install ...
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#14
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Quote:
Found a old 5/8” spacer too. Anyone care to share their mods so I can copy (grin) while I have the grinder out?
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1963 Cat SD Clone (old school) streeter 1964 GTO post coupe, tripower, 4speed (build) 1965 GTO 389 tripower, 4 speed, driver 1966 GTO dragcar 1966 GTO Ragtop 1969 Tempest ET clone street/strip 1969 GTO Judge RA lll, auto 1969 GTO limelight Conv. 4speed go and show (sold) 1970 GP SSJ 1970 GTO barn find..TLB…390 horse?….yeh, 390 1972 GTO 455 HO, 4 speed, (build) 1973 Grand Safari wagon, 700hp stoplight sleeper 525ci DCI & 609ci LM V head builds |
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