Cam selection 408W

[Jan 12]

I have a question for the cam gurus out there. In my 69 Mustang sportsroof I've got a newly built engine that I am not entirely satisfied with.

 

Here are the build specs:

Ford 351W stroked to 408

84 block
Compression 10:1

AFR 185 Renegrade 20 degree

Edlebrock RPM Air Gap intake
FiTech Go EFI

TKO 600 5speed transmission

3.89 gears

Tire size 245/50-16
Cam Howards 222735-12 (Hydraulic Roller)

It puts out around 500hp and just as much torque which is all well.
My problem is that it difficult to drive “smoothly” under say 1800 rpm.

It's very jerky and annoying driving around in city traffic.

It's obvious that the cam is too wild for me and that I will have to replace it.

I have given all my engine details to Howards and they recommended 220325-12.

My engine builder now recommends 222745-12.

 

It would be good to hear from anyone with a 408W what your experiences are with different cams.
(comparing cams with a smaller engine displacement will not be relevant)

Any advice would be greatly appreciated, I want to get it right this time as I don't want to change cams a third time.

Thanks

[BuckeyeDemon 211]

i think i have a similar cam (236/244, 614 lift) with 1.7 rockers (makes the cam look a little bigger as compared to 1.6's) in a 418w with a Vic Jr single plane manifold (i don't know where yours is degree at though....).  also have a tko600 and 4.11 gear.

on mine i had to make sure i had the initial timing pretty high (around 20). it would want to surge/buck at cruise if under around 1500 rpm.  the throttle down low was a little unresponsive as well.  it was just way too lean down at that 1500 rpm range and lower requiring some adjustments to the carb (primarily idle jet/low speed bleed) to richen it up just enough for that to all stop.  Mine is a carb (950HP) and I don't really know FI, to know how they need to be compensated.  Mine is about 11 inches of vacuum at idle.

[barnett468 418]

Yup, you must set your initial timing and timing curve to the optimum level to get the optimum performance.

The EFI is causing the problem . You can't run big cams with it.

I would run the cam howards suggested over the one your builder suggested . if you have 1.6 rockers and this cam works well for you but you want a little more power you can then try 1.7 rockers if you don't already have them.

 

 

[BuckeyeDemon 211]

have you tried adjusting the EFI settings?  it would be sad to think that EFI system doesn't have the knobs available to adjust to a cam like that.

[Jan 12]

I am running 1:6 rocker and 13° initial timing.

I first had a Quick Fuel 780 carb before the EFI and it was just as difficult to drive at low rpm:s then.

As I won't be changing the cam before winter I will play around with timing and settings in the EFI.

The only "hard" setting I do with the timing is the initial setting, the distributor is locked and the EFI controls the rest.

Thanks for the suggestions.

[ray1970 88]

I have changed from locked EFI timing to normal dis..timing at lest 5 times.

I gave up on EFI timing.

And below 2000 rpms my carb always worked better.(changed 6 times)

NOT to say you cant make it work but it will take time.

[Jan 12]

I have now changed the initial timing to 19° and I can now cruise in 5th gear at 1500 rpm without too much surge/bucking.

I also got back a little of the V8 rumble sound that I was missing.

I will continue adjusting the EFI to try to improve the situation further.

 

 

[fordguy69 24]

My FiTech works fantastic with a fairly large cam.  The FiTech has 4 settings for the cam in the software.  I found that mine runs best on 3.  My cam duration is 238/246 @.050 and pulls about 10.5 inches of vacuum at idle.  I have read that some folks with only 8 inches or so are running the FiTech on 4 and it works great.  

I don't use the FiTech timing option only because I already had my MSD ready to run set up and curved before I installed the EFI,  19 degrees initial, 36 total all in by 3000.  (Timing specs suggested by the cam grinder and he was dead on.) 

 

 

[BuckeyeDemon 211]

1 hour ago, fordguy69 said:

My FiTech works fantastic with a fairly large cam.  The FiTech has 4 settings for the cam in the software.  I found that mine runs best on 3.  My cam duration is 238/246 @.050 and pulls about 10.5 inches of vacuum at idle.  I have read that some folks with only 8 inches or so are running the FiTech on 4 and it works great.  

I don't use the FiTech timing option only because I already had my MSD ready to run set up and curved before I installed the EFI,  19 degrees initial, 36 total all in by 3000.  (Timing specs suggested by the cam grinder and he was dead on.) 

 

just curious, but what cylinder head are you running?  36 seems like it may be on the high side (or is this some open chamber or stock cylinder head motor?)