FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: stuart olson on December 01, 2020, 12:06:20 PM
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Hi all. About to get my block, heads, and rotating assembly from the machine shop. Ive got a 66 LTD 4 door that is a road trip machine for myself and up to 6 of my freinds. Its going to be a 445 with home ported C6AE-R heads and a CJ intake. Auto, power brakes, power steering, stock converter, and 2.89 gears. Get to 80-90 fast and stay there till you pull over for gas. I was thing something like a CJ "copy" cam such as a howards https://www.howardscams.com/hydraulic-flat-tappet-american-muscle-camshaft-1963-1977-ford-352-428-1100-4800-howards-cams-257711 described as a copy of the C6OZ-6250-B. The guy at the machine shop (who I belive to be very reputable) was thinking a comp cams 33-308-4 224/230 at 50 .551/.539 110deg lobe seperation. Any thoughts from the comunity?
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What's the compression ratio? What do the heads flow?
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If you "don't" go with a custom cam from Brent, the Comp cam you showed is a better one for what you are doing than the C6OZ replacement.
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Have Brent grind you a cam, you won't regret it. I got one of his cams for our 445 in my race car and it made it a monster.
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Your compression ratio will mean quite a bit, if you want to run straight pump gas. The higher duration will help in doing that.
I too, would would go with the 224*. It will also kill of some of the dynamic compression to help with pump gas.
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Normally wouldn't suggest a 224* for a straight cruiser with a lot of weight and that gear, but 80-90mph is 3000-3300rpm where that should be well up on the cam with a 428. I think it would work fine. Also think you'll be looking at 8mpg if lucky.
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A 445 with 10:1 will need a 270/224 lobe retarded to 110 ICL or it will be fussy on fuel and timing. I ran a 270H in one in my truck and it had a ton of torque even at 110, but ran better everywhere with a 282S equiv 112 LSA on 108. That was 4200 lbs, 3.50 gear with 33 inch tires
That Comp cam isn't a bad cam, its a 270H intake, 280H exhaust, but you'd have to rock it back unless somehow you were well below 10:1
The Howards cam is likely better on fuel tolerance, but is just too weird for a healthy 445. Low lift, not enough .050, miserable ramps, etc
FWIW - I run a 280/286 230/236 112 LSA on 106 custom grind in my 462 and it peaked at 5000 with a Victor EFI intake. Don't undercam it. Calculate compression, better describe the heads, but likely neither is optimal for off the shelf 445 parts,
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With the C6AE-R heads in mind, a 6° split on that universal camshaft is about 6° less than what it needs to be. That's a Chevy cam ground on an FE core and would need a compression ratio of no more than 9.5-9.6:1 to run reliably on pump gas with that weight and rear gear.
Without knowing the compression ratio, any camshaft is going to be speculation at this point, and the actual specs will depend on any flow numbers that are available on those particular heads.
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Not sure about head flow numbers, but its 9.66:1 compression. CJ 2.09 1.65 valves Isky 805-DO springs. I belive I asked him to flow the heads when I checked the block work but havent heard back yet.
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Flow numbers would be nice as it affects the duration.
If I were to assume something like 250/160 on flow, I'd be at 221/229 @ .050", 108 LSA, 105 ICL, .550"-ish lift. The more details I have the more accurate I can be.
57° of overlap on that one, still will have vacuum for days if the engine is sealed up right, as you have a big cylinder pulling on a small port. Slight lope.
This should work with your valve springs as well, *IF* they are installed at around 1.900". You'd end up at around 115 lbs seat and 295 lbs open, probably even a little less than that on the open pressure as you'll lose a little lift to geometry/deflection. I have my flat tappet cams ground with 4° of lobe taper and with an oiling lifter, such as a Crower Camsaver, there would be no issues with cam break-in at those pressures.