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Hydraulic Roller vs. Hydraulic Flat Tappet

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Old Jul 6, 2003 | 08:57 PM
  #1  
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From: Flowery Branch, GA
Car: 1985 Iroc-Z
Engine: 1 BA 305 TPI
Transmission: Probuilt 700R4 - 2800 Stall Midwest
Axle/Gears: 3.42
Hydraulic Roller vs. Hydraulic Flat Tappet

Which engines have HR and which have HFT? My '85 305 has the HFT I believe. I am trying to find a cam that will work well with my engine. Some of the cams that I have seen recommended on the site are HR which will not work for me. What cam do you guys recommend for my setup? I am adding S/R Torquer 305 heads, 52mm Throttlebody, possibly 22# or 24# injectors and aftermarket base and runners.
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Old Jul 6, 2003 | 10:43 PM
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Car: 1991 Z28
Engine: 305 TPI under 14 psi
Transmission: aftermarket T56
Axle/Gears: Moser 12 bolt 3.08 gears
85-86 TPI motors are FT and 87-92 TPI motors are roller. If I remember right your car actually came with a decent cam in 85. But something like a crane powermax 2040 FT cam would work great imho.
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Old Jul 8, 2003 | 11:24 AM
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From: Springfield, MO
Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
comp xe 256 or 262.
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Old Jul 8, 2003 | 06:13 PM
  #4  
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From: Flowery Branch, GA
Car: 1985 Iroc-Z
Engine: 1 BA 305 TPI
Transmission: Probuilt 700R4 - 2800 Stall Midwest
Axle/Gears: 3.42
Right now I am leaning toward the XE256.
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Old Jul 8, 2003 | 06:57 PM
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From: loxahatchee fla
you should read this

http://www.idavette.net/hib/camcon.htm
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Old Jul 10, 2003 | 11:03 PM
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From: Springfield, MO
Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
If you want to spend the money on a cam that is optimal for the 305 (or anything for that matter) then yes the roller is the way to go. But if you have plans to ditch the 305 for a 350 in the future do you want to spend the money on another roller cam at that time? But keep in mind I'm a cheap bastard and will not spend any money on the LB9 longblock in my 92 car, just slowley gathering parts for a 350 for when the time comes to replace it.
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Old Jul 10, 2003 | 11:56 PM
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From: Flowery Branch, GA
Car: 1985 Iroc-Z
Engine: 1 BA 305 TPI
Transmission: Probuilt 700R4 - 2800 Stall Midwest
Axle/Gears: 3.42
I'm kind of partial to my 305. I love the looks on the face of the guys at the track when they find out that there 350 just got beat by a 305. Priceless. I don't mind putting money into.
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Old Jul 11, 2003 | 03:15 AM
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From: Seattle, Washington
Car: '87 IROC-Z/'82 RX7
Engine: SBC 355/1.1L Rotary
Transmission: T56/5 Speed
Axle/Gears: 4.33/3.93
With the heads I'd go with the 262. It makes alot of torque and I'm using it in my 350. 305's seem to like alot of cam from what i've read.

Call comp and ask them.
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Old Jul 11, 2003 | 05:57 AM
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From: Springfield, MO
Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
Well, if your gonna stick with it then the money spent should pay off. I guess in that case I would go roller.
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Old Jul 11, 2003 | 03:24 PM
  #10  
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The 52 mm TB is going to be overkill on a 305 as will the 24# injectors. Get a good set of used 22#'s and have them cleaned and flow matched. Save the money from the TB and brand new injectors and pick up a set of used 'Vette alum heads and have them ported or port yourself. and maybe have them milled to raise your comp from 9.5:1 to 10.0:1 or so.
A good flat tappet cam would be something in the 204-214 intake duration @.050 and 204-220 exhaust @.050. This should net you some very good torque numbers and keep it quite streetable too.
Hyd roller conversions are quite expensive, but if you are willing to spend the money, they will get you some decent power gains.
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Old Jul 11, 2003 | 05:24 PM
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From: Frederick, MD USA
Kick a s s times at the track man! I'm impressed..Were you running slicks? What 60'? Do you have a list of the times with each of the mods? 13.70's with those mods is really good man..Keep me informed on what you run with the upper motor work!
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Old Jul 11, 2003 | 05:49 PM
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From: Flowery Branch, GA
Car: 1985 Iroc-Z
Engine: 1 BA 305 TPI
Transmission: Probuilt 700R4 - 2800 Stall Midwest
Axle/Gears: 3.42
Morley, I was thinking that I would need the 52mm to get more air. It seems like the intake is going to be my restriction once I get the new heads. I am thinking of going with the Edlebrock base and runners. I will probably go with the 22# injectors once I learn how to burn my own proms. My cam choices to this point have come from Engine Analyzer which has been very accurate for my car so far. It show that the 212/218 is the best choice to keep the low end torque that I have now. The 218/224 give about 10 more horses on the top end(above 4500RPM) but loses about 30 on the bottom end (2500RPM).

Yarnboy, thanks, my 60' times are between 1.8 and 1.9. I am running BFG Drags(best drag tires).
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