CAM help

Hi all this is the first time i have posted on here .Im planning on building a Southern GT40 from mike sollis at southern GT .
i am in the early stages of getting bits and bobs together and working on my engine which is where i need a recommendation on the HYDRAULIC ROLLER CAM i will be using the car for street driving so low down torque is important to me .below is a list of bits going in my Engine.Any advice will be appreciated

1971 FORD 302 BLOCK STROKED TO 347​

• Hawk Racing 4340 FORGED STEEL CRANKSHAFT
• 5.315" .927 PIN 4340 H-BEAM RODS
• MAHLE 412g -6.6cc FORGED POWER PACK PISTONS
• SET MAHLE FILE FIT PISTONS/RINGS
• CR 10.74
• SBF 302 ROD RACE BEARINGS SET
• SBF 302 MAIN STD. RACE BEARINGS
• 28.2OZ FLUID DAMPER
• BILLET TIMING CHAIN WITH TORRINGTON THRUST BEARING
• BILLET STEEL MAIN GIRDLE
• WINDAGE TRAY
• 1.6 3/8 HIGH PERFORMANCE STAINLESS STEEL ROLLER ROCKERS
• ARP302 SUPER DUTY OIL PUMP DRIVESHAFT
• HI VOLUME OIL PUMP
• AFR-1422 185cc, 58cc STUD MOUNT SB FORD HEADS
• ARP SBF FORD STAINLESS STEEL 12PT ENGINES FASTNERS KIT
• **** HAWKSRACING H/S COMPUTER BALANCED ****
• TWM 50mm IDA THROTTLE BODIES and MANIFOLD
 

Attachments

  • !Bj0TwlgBWk~$(KGrHqIOKioEsmc0,(!gBLU8rV,SmQ~~_12.JPG
    !Bj0TwlgBWk~$(KGrHqIOKioEsmc0,(!gBLU8rV,SmQ~~_12.JPG
    30.2 KB · Views: 236
  • !Bj0TzIg!2k~$(KGrHqMOKjUEsnLf!v9gBLU8reC+o!~~_14.JPG
    !Bj0TzIg!2k~$(KGrHqMOKjUEsnLf!v9gBLU8reC+o!~~_14.JPG
    1.2 KB · Views: 411
Last edited:

Jim Rosenthal

Supporter
You might want to submit these specs, and your transmission ratios and tire diameter etc to Comp Cams and ask them what they recommend. Most builders put way too much cam into their engines. A cam that will give you good low-end torque and good street driveability may be all done making power by about 6000 revs. In your favor is that a hydraulic roller can spin up higher than a flat-tappet roller, and your EFI will allow you to use a more aggressive cam without an impossible idle and no low-end power. That engine sounds like it should be good for 7000 revs, anyway, which gives you a fairly large range to work with.
 
You could also try out a company called AFM (Anderson Ford Motorsport). they have a line of cams called Hi Rev cams, that are supposed to be able to rev north of 6500 rpm with hydraulic roller lifters. Now they are more into 5.0 mustangs but I am sure they could grind something good for you too, be sure to mention that you are using an IR intake system, as I think a few things need to be different as compared to a more traditional style intake.
 
You will find that virtually all of the hydraulic rollers have a 'recommended' upper RPM limit of around 6500 [ which is at odds with jimbo's radical & innovative flat tappet roller, still they say you learn something new every day:) ].

The only items I would question in your parts selection are the 5.315" rod/1.165" pin height piston combo [ 5.400"/1.070" are the preferred numbers for a sporty application, the Hi-Volume oil pump, and the 10.74/1 comp ratio which might be a bit high for pump gas in the UK, but I would leave that to your local man.
 
You will find that virtually all of the hydraulic rollers have a 'recommended' upper RPM limit of around 6500 [ which is at odds with jimbo's radical & innovative flat tappet roller, still they say you learn something new every day:) ].

The only items I would question in your parts selection are the 5.315" rod/1.165" pin height piston combo [ 5.400"/1.070" are the preferred numbers for a sporty application, the Hi-Volume oil pump, and the 10.74/1 comp ratio which might be a bit high for pump gas in the UK, but I would leave that to your local man.

i have gone with shorter rod and pin to eliminate oil ring intersection stopping oil burning problems .The cr can be lowered with a thicker head gasket (copper 0.0061 will give 10.015cr ?) i will also be using super unleaded (98 ron)plus alloy heads will help
 
Last edited:
Thanks Jim i have contacted comp cams a couple of times now and each time they have recommended different cams ? and both have recommended cams for 1986 up where my block is a 1971 so have contacted them to clarify about if they fit but no response as yet after several attempts
 
Philip,
you need to select the cam arround your TWM setup or the motor will be awfull. We are TWM agents so have been through all that, give me a call or PM and I can sort it out for you.
Mike
 

Ron Earp

Admin
You will find that virtually all of the hydraulic rollers have a 'recommended' upper RPM limit of around 6500 [ which is at odds with jimbo's radical & innovative flat tappet roller, still they say you learn something new every day:) ].

A flat tappet roller huh? Been reading this thread with interest on cam selection as I'm doing the same for my BB Ford now. Seems I'll have to go back to the drawing board.
 
Hi Mike is that Mike Huddart as in Huddart engines ? well yes i would like your help please i will also be needing a ECU to set it all up eventually . i am a total novice in this area
 
i have gone with shorter rod and pin to eliminate oil ring intersection stopping oil burning problems .The cr can be lowered with a thicker head gasket (copper 0.0061 will give 10.015cr ?) i will also be using super unleaded (98 ron)plus alloy heads will help

Oil Burning with the so called' oil ring intersection' is due to any one or a combination of the following- incorrect oil ring/piston combo choice, incorrect installation of support rail in oil ring groove, lower rail of oil ring installed wrong, poor bore preparation ,hone pattern of bore surface etc etc... as long as the surface for the 'top rail' of any three piece oil ring is above the pin bore this so called problem is a builder or ring installation issue.

Installing a thicker head gasket & thereby increasing the piston to head ( Squish ) distance will increase the likelihood of pinking & detonation- to lower comp ratio , the only way is to increase the head combustion chamber vol or piston dish size vol.... [/I]
 
Back
Top