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Duncan Mach72

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About Duncan Mach72

  • Birthday 12/01/1961

Vehicle Info

  • My Car
    1972 Mach1
    351C 4V, 4 speed
    Alum flywheel
    McLeod clutch
    Torque biasing diff, 3.5:1
    31 spline Strange SS axles
    Dual 2.5" exhaust


  • Location
    United Kingdom
  • Region

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Enthusiast (6/14)

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  1. Here's my recent experience. My car is very similar, only drivetrain difference is I have 3.50:1 gears. I used to run a Ford M6250A341 cam which has 510/536 lift & 214/224 duration at 50thou. I had a Performer & a 3310 (750VS) Holley. This was really tame! It delivered easy driving bottom end, you could make a sharp turn in top gear & drive off normally! Not really what I wanted from a musclecar with a stick, I want to work it & be rewarded. After driving round with a 429 with similar cam (lame top end, 14s/98 quarter mile) I recently put the 351 back in with a better cam & manifold. I reasoned if 0.5" lift was tame but 0.6" was race spec then I wanted 0.55" & figured I wanted to go up on duration to about 235/245. I struck lucky as a guy near me was selling a brand new Lunati solid lifter cam (41107LUN Grind SP02-305) 0.55/0.559 237°/247°LSA 108. Quoted Rpm range is 3200 – 6800. Basically with a 351C 4V it appears that if its cammed for 5500 rpm you will have 350 hp & if it can make 6500 rpm you will have 450hp. That's how the heads seem to work. I also got a Performer Air Gap at a good price, I am still tuning & because I am using a "too big" carb (850DP). I have just blocked off the plenum divider cutout, which is a crutch for a small carb. Prior to this the air/fuel ratio was all over the place but even so when I gassed it at 3000 rpm it pulled really hard, made me grin & I have not been above 5000 rpm ish so far as I'm supposed to be running it in. Looking forward to the next test drive/tune session this weekend. Get a good cam, ditch the Performer, don't look back!
  2. You really need a more secure connection. As it is now, a bit of dirt or corrosion & you won't have a circuit. You really need to cut off the ring terminal, cut the original lead off a few inches back, splice both leads together to the one socket (or boot as you call it). Also, did you remove or bypass the pink resistance wire from the ignition switch? The Pertronix needs direct 12v feed I believe. You know on the original circuit the coil has a non-resistor feed from the solenoid when cranking and then the resistance feed when running? If you only have it connected to the 'run' position it won't spark while cranking. That one caught me out.
  3. Changed the oil on the recently rebuilt 351C from Amsoil Signature series 5w-30 to Fuchs Titan Race Pro S 10w-50. I'm a firm believer in modern synthetics after reading 540rat's oil test blog. However with the 5w-30 pressure was dropping right off when it got hot. The issue is that I am using a stock pump & have worn lifter bores. I should really have had them sleeved. I didn't put in the hv pump I have as previously it used to empty the sump into the valve covers. So I put the 10w-50 in as a temporary crutch. Went for a half hour cruise around & it's a lot better, lowest oil pressure I saw was 40psi at idle & low speed cruise. The longer cammed soild lifter 351C with aluminium flywheel drives very differently to the short cammed 429 I used to have in the car. Only gone to 3500 rpm so far, cam is good for 6500.
  4. I also have the V6 master cylinder with aftermarket proportioning valve like the Wilwood shown. With stock front discs & rear drums I have had to turn the prop valve all the way closed and depending on what tyres I have on the rear they still lock up first sometimes. Anyone got ideas on how to improve this?
  5. It has been below freezing & snowing most days this week in the UK. Today is a bit better, 4 degrees Celsius after a 1 degree start & some sleet. Snow is now melting. My mate came over from the post-industrial city of Sheffield to help me fire up my rebuilt, forged piston, solid lifter Cleveland motor. The garage was warm enough & we just pushed her backwards til the rear was out in the carport. It all went pretty well, fired right up, 70psi oil pressure at 2500rpm & cold, from stock Ford pump, around 60 when it warmed up. Ran her for about 15 mins total, between 2000 & 3000 rpm. Finally dropped down to 1500 & set timing. Going to run some more another day before installing lambda sensor, checking valve lash & setting idle. Looking forward to some dry warm weather soon to get her out for a test drive on the local bypass. The way it's been lately it could be quite a few weeks to go.
  6. Understand the stock look thing, fair enough. With alternator, 200A x 13.6v = 2720 Watts so you could install a 2kW sound system in there...maybe not what you want.
  7. Nice build but why the 200 amp alternator? - not criticizing, just asking! Also, I think you should ditch the mechanical fan & fit a pair of electrics, will gain a bit of performance & economy, plus a nicer, safer place to work when doing timing etc!
  8. The last time I had the heads off my Cleveland I used the gaskets without the heat passage hole, not realising they won't hold up. When I took it apart they were burned thru. This time I have cut pieces of aluminium bar, filed to fit & driven them into the heat passages on the intake side of the heads. I used a very small amount of sealer too. But then I scored a s/h RPM Air Gap to run instead of the Torker I was going to use so I needn't have bothered! Fire up estimated in 2-3 weeks.
  9. I've had EBC Yellow Stuff on my 72 for a year. They work really well, don't fade on repeated application & don't seem to produce much dust relatively speaking. I have pulled the car down from nearly 100mph numerous times with them - my local strip has an early turn off otherwise you go to the end & turn around. I always take the early turn which means braking quite hard. I was thinking of a Wilwood kit previously but I'm now happy with what I have got.
  10. Hi Finmach. thanks for advice. I've been researching C4 vs C6. It seems that C4 can be built to take lots of power but will require frequent clutch replacement. C6 can nowadays be cheaply upgraded with E4OD/4R100 6 pinion planetaries etc & torrigton bearings for less friction. There are some guys on the 460 forum running a BBF powered altered into the 7s with a nearly stock C6! I'd love to buy a lot of those parts from you but sadly my finances are fully committed for the next 6 months on a new blown methanol BBC for our altered and then we will have to replace the stock case powerglide too... Maybe in a few months I can afford to buy the front bumper from you.
  11. Something else to be aware of - with 17" rims the front wheel rim is right in line with the end of the upper A-arm - I had rubbing problems when the front end went light. Here in the UK 18" rims are a far better choice than 17s as there are almost no decent tyres for 17s that are not crazy low profile but there are many choices for 18s. However low profile tyres on leaf spring cars do give a harsh ride. In the rear I think 5.5" backspace would be optimum with 9 or 9.5" rims. You definitely don't want much more than 4.5" on the outside. So a 9" rim (10" overall width) with 5.5" backspace will have 4.5" on the outside. If you err on this side, you could always space it out a little if required to tailor the looks.
  12. Thanks for all the advice folks. At the moment I run the ordinary Hoosier Quick Times which I think are bias ply? I'm putting the original 351C back in for this season with a 0.55" lift solid lifter cam, 10:1 cr, forged flat tops & an Edelbrock Air Gap. I managed to get these parts together over the last 5 years at good prices which is useful as funds are a bit tight at the moment. Engine is in the car, I am swapping the toploader input this week. Be interesting to see how it goes. 385 build will have to wait til next winter.
  13. > Is that 2.24sec 60' with street tires or slicks? Embarrassingly on Hoosier Quick Times, 275/60/15. I started the season on 255/50/17 street tyres and had so little traction I had to baby it off the line. I got used to doing that over 3 meetings, then I got the QTs & did another 3 meetings. I was told I would not need to burnout the QTs. Wrong - wheel spin at shift into second cost me my first possible final round win. I've been afraid to really hit the clutch hard as I was afraid of twisting the small input shaft plus I was trying to keep a consistent launch. I'm putting a big input in the gearbox this winter so I hope to hit it harder & drop the times some.
  14. I have noticed that all of the fast cars in my class (10-12s) run Caltracs. Are the split leaf springs ok to drive on the road? Yes they work well just run a good adjustable rear shock like a QA1 . Then stiffen them up at the track and back em off for the street. Sounds good, if things work out financially in 2018 I might do that. My pb 60' is 2.24, I think it's an area where I can pick up quite a bit!
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