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#1
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Has anybody been using the Rhoads lifters? I know they sound like a solid below 3500rpm, but how would they work in a 400 with a medium cam? My cam is a single pattern 244@.050 duration/.501 lift with 1.52 rocker. I was going to change the rocker to a 1.6 or 1.65 to increase my lift/duration above 3500rpm with the Rhoads? What do think?
Thanks, Guy |
#2
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Has anybody been using the Rhoads lifters? I know they sound like a solid below 3500rpm, but how would they work in a 400 with a medium cam? My cam is a single pattern 244@.050 duration/.501 lift with 1.52 rocker. I was going to change the rocker to a 1.6 or 1.65 to increase my lift/duration above 3500rpm with the Rhoads? What do think?
Thanks, Guy |
#3
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your cam is pretty agressive. you would benefit greatly with the use of rhoads. i have run rhoads lifters with no problems for many miles. they work as advertised. apparently, an aggressive lobe ramp can make them very noisy but i have never been bothered by the slight noise they have made with the cam i use.
if you don't mind the ticking, i would use them based on your cam specs. |
#4
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I have Rhoads in my 68 GTO 400 all stock except for a 69 Ram Aiv cam and Ram Air exhaust manifolds. They work great. It's very lumpy on idle when cold, but when it warms up the idle is smooth and I have plenty of vacuum.
TigerEFI.com (Classic Pontiac Fuel Injection) Classic Pontiac EFI Forum Jack@TigerEFI.com 68 GTO, 455 JBP EFI, 6 Speed Dual Overdrive Motto: Build it for NASA and drive it like you stole it!
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TigerEFI.com (Classic Pontiac Fuel Injection) 2004 GTO Company car, 1994 TA 25th Anv, 1971 Grand Safari Wagon, 1968 GTO EFI, 1968 GTO Stock, 1968 GTO Convertible in desperate need of restoration. |
#5
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You will like them with that combo. Just follow their directions that come with them.
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Have A Great Day |
#6
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should i go to bigger ratio rocker than the 1.5? If you go to carcafts events, look up 15 proven dyno combos and see my numbers now. It runs pretty good with the johnsons about 10 inches of vacuum just below a 1000rpm(alot of tuning). It's pretty punchy.
My thinking is I could gain at bottom and top. Also I'm bring the heads in to look at the base line flow(current). Maybe with heads ported and polished it will work better with 1.5 rocker/rhoads lifter thanks for the replys!!! |
#7
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If you have D-port heads you would need to elongate the push rod slots to use 1.65 rockers and possibly even 1.6s. So, if you have them off to have them ported, I would have that done. If you put them on the flow bench, you may find that either the intake or the exhaust would need a different ratio rocker to give a better flow ratio between the two. Also, if you have the slots elongated, you can always try the higher ratio rocker!
Bill
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Bill 64 GTO, tube chassis w/606" IA tall deck, PG & a pro geared Fab 9". 2750 lbs. 8.2550@164.17-1/4, 5.2901@131.97-1/8, 1.1981-60-ft. 8/10/08 |
#8
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I use the Rhoad's lifters. I ran std lifters first, then switched them out after about 1000 miles. What I saw was improved vacuum at idle and slightly smoother off idle performance. Prior to the switch I was seeing 12" vacuum at 1000rpm, 7-8" at 750rpm and 6-7" at 700rpm in gear. The Rhoad's improved all the numbers by about 2" of vacuum. It runs pretty much the same from about 1500rpm up. At the track no difference at all. I also took the time to swap out a std set of lifters for Rhoad's lifters on a 500hp 455 street engine at KRE. The Rhoad's lifters ran exactly the same numbers as std lifters on back to back pulls. So we loose nothing by using them.....Cliff
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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), |
#9
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Thanks for your replys...
First off my car is a 4spd,3:55 gear/3:71ratio with current tire. Cliff did you see I was the only Qjet of the bunch of the car craft 15 proven? I saw your work/Qjet(barely)on Jim Hands wagon picture in the Carcraft feature. It look like you modified the top of the carb with air flow deflector of something??? How can I get hooked up with that set-up? Also I was thinking of using the 1968 ram air set-up for the air cleaner, does the HO set-up work better or the ram air set-up? I plan on using the Rhoads this time around...I'm ccing everthing this weekend also checking my valve to piston clearance of the current combo. I'll know alot more when this is done and base line head flow. Thanks again for your time here. |
#10
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Jim Hand did all of the work to the top of the carb. He made some air deflectors but I'm not sure what material was used? The carb that I sent to him for the Wagon is a late model Pontiac carb, 1978 if I remember correctly. It was recalibrated in all areas based on his Wagon's engine/drivetrain specifications. The castings were not touched in any way. I was interested in getting an idea of how the late model "smog" carbs ran, what better place to send one for testing! Anyhow, it worked well enough that I didn't get it back!!.....Cliff
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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), |
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