[62fatcat]

on the topic of camshafts.
i curently run this cam
comp 288/300 seat, 260/268@.050 with .440 lobes(net lift is .700) it is ground on 114-- lobe seperation and it likes a -----109 instaled position.
---best run 8.97@ 154mph with 27# boost, 335cfm e heads and the f-2, a 477 ia2, c-16
---fuel, 24*timming.
i also have this cam
---comp 318/332 seat, 282/292@.050 with .484/.440 lobes(net lift .772/.700) also on
--- 114 lobe seperation.
----this cam ran a 9.44@147 with ported dports(275cfm), (24#boost), a 468 stock
----block combo, 110 fuel, and 24* timing.
the converter stall is 5400, and i shift around 7000-7200, the fall back is about 700 rpm and the slipage is about 5%.

so dose anyone think the bigger cam will make the car faster??
what about the bigger cam and e85?
i have tested the c-16 versus the e85 and the temp drop goes from 310 to 130 under the carb(1/8mile temps), everthing else the same, just the differnt fuel and carb settings settings

thanks,
brad.

[Travis Q]

Hard to say if the bigger cam will be faster. Judging by your shift rpm, I would guess that it would not. I have used camshafts similar to the second profile you describe (the big one!) in some centrifugal supercharged small block Fords and Chevrolets. Actually, some of the cams were even a little bigger than the one you listed, especially in valve lift. We had to shift themat around 8800 rpm.

I would think that a 477 would like a little bit more camshaft than the first profile, especially more exhaust split and most certainly more lift. I would probably look for something around 268-272 ish on the intake lobe, around 284-286 on the exhaust side, with absolutely as much lift as you can handle. Don't be scared of .850 lift so long as you have the seat pressure and valve to piston clearance to handle it. Big pushrods, too!

I know this goes a little beyond the scope of your original question, but thought I'd throw it out there anyway. The F2 can make a bunch of power! Blower engines like big camshafts and lots of engine speed.

TQ

[BruceWilkie]

Without knowing the flow curves of your intake exhaust its a tough call. I'm agreeing with travis, probably in the 270's on intake and 8-12 degrees more on the exhaust. Maybe LSA of only 113 or it might want 115-116 LSA and maybe around 109-111 ICL its hard to say without knowing the flow balance and curves.

Changing to the bigger cam will affect your rpm range and convertor requirements too. Alcohol cars generally run a bigger duration split than race gas due to greater volume of fuel consumed.

[Tom Vaught]

In 1998 we ran a Vortech Supercharged 347 cid Engine in Jimmy Keen's Mustang. The car at the time would run very low 8.3xs at 165 mph.

I changed the camshaft & the headers, and we ran 7.96 at 172 mph.

The original camshaft was a Cam Motion Roller with .735 lift and 69 degrees of overlap at .050 lift. The lobe separation was 112. No advance in the camshaft.

I changed the camshaft by reducing the overlap at .050 to 57 degrees, advancing the camshaft 5 degrees, and changing the duration numbers at .050 to 276 Intake and 292 exhaust. The engine really liked the change. Like I said we went a bunch faster.

We changed the headers from a 2" header to a stepped header: 2" 6" long then 2.125" 12" long, and finally 2.250" for the last section of pipe to the larger diameter collector. The overall length was tuned for 9000+ rpm.

Food for thought, Brad, on the event timing.

Sometimes you go faster and make more power will less intake duration and more exhaust duration (to remove the spent gases) on a blower car. Most Turbo cars I have worked with had a few degrees less exhaust duration vs intake duration.



Tom Vaught

[62fatcat]

Travis, Tom, and Bruce,
thanks for the input.
i had the .050 numbers wrong, i looked it up in the compcam lobes, and it is 278 and 292and the overlap is 57*@.050.
i think i will give it a try for next season.