Another Super Victor?
YR, ya lost me on upping the intake.....I always thought we use split cams to make up for the lower flowing exhaust side. Can't say I ever saw a split with the intake being longer. Would you mind educating me on your suggestion?
Have to spec out a cam soon. Definitely going to tighten the LSA to the 106ish range.
Oh...4 speed. 4:10's
The question I always have is did we add exhaust timing or reduce intake timing? Who knows? If you are burning gasoline and you even have a reasonable exhaust port, and 260*'s at .050 is getting you the RPM you want, there is no reason to add exhaust. I'm still a big fan if asymmetric single pattern cams for most everything.
IMO, that extra exhaust timing is eating up what I call midrange power for an engine like yours. That and an LSA that is probably wider than it needs.
Along that line, if you pull in the LSA, you may need to add a bit of duration to both sides to keep the RPM range from moving down, i.e. what you now feel at 3500 you might feel at max RPM.
Alcohol engines require some split, because the exhaust is heavier. Other than that, no reason to split them, except again, maybe some weird Ford stuff or some unusual, exceptional deal.
If your exhaust/intake ratio is near .78 or higher, you may need to REDUCE the exhaust duration with a split. Say, 265/260 I/E to help the intake side. You have to fill the chamber first.
You need to talk to someone way smarter than me to sort it out, but I'm just not a fan of dual pattern cams unless the cam grinder can tell if he added exhaust or reduced the intake. IMO, most of the time, they reduce intake duration to help with idle characteristics and open the LSA to get the RPM back.
I didn't buy my last cam from Cam Motion or Jones Cams because they both wanted a split duration deal and they gave differing reasons why they were doing it. And both had a wider LSA than I thought was needed. Don't mean I won't use either of them again, just meant with the induction prepped as I did it, looking at my flow numbers in both directions and what the ports looked like at overlap, I couldn't justify a cam like that.
FWIW I ended up with a cam that is 281/255 281/255 .620 .620 105 installed at 105 for 340 CID at 7K shift speed. It lashes at .014/.016 hot.
One of the other cams was something like 240/248 .578/.500 111 installed at 106 and that looked wrong to me. He was stuffing exhaust at it and opened the LSA to get to 7K because it was short on timing. And advanced the cam to make it pull lower by closing the intake sooner. That much was admitted by the cam grinder. IMO, that grind would have been a PIG at 3-4K right at the bottom of my gear change. This is for a car I drive almost any day it's nice.
Hope this clears up some of what I've been trying to get across. It takes a certain amount of time to fill a cylinder. The better the head, the less time to fill the same sized cylinder, so you can run less timing with better heads. The point is, it still takes TIME to fill the cylinder. That is intake duration. Nothing more. You can manipulate the other events to reduce the intake time, but you have to give something up to do it.
Your cam looks like that. I'd like to see the seat timing numbers and the at .200 numbers on you cam if you have them.