[scott70]

Originally Posted by Skippy597

Thanks Lee. That's a big move to drop off 8 degrees on the intake side from what I've read everywhere is that would put it below a hydraulic Ram Air IV grind. I'm thinking with the increased exhaust duration and wider lsa than you ran 112 vs 108 I think it will be ok??? Maybe... I'm not sure but I think I'm gonna try the custom crower SFT cam. If it's terrible I can change it later it's not a big deal or big investment compared to a roller setup. I might loose lash it a hair to give the bottom end a boost.

I used to run the UD 255/263 SFT and that cam liked around 5900 shifts also. That was a nice cam.

[Jay S]

Did Crower give you the seat timing numbers for the custom cam?

[Skippy597]

I do not but I just sent an email and they've been great at replying

[Steve C.]

See if this will work....


CAM & VALVE TIMING TAGS

https://crower.com/cam-card-finder

Also here in the upper left corner

https://crower.com/

It used to work with my custom cams number. But not now.
It might with yours.

.

[Jay S]

I will wait and see what the Crower custom cam looks like, not enough info to really say what it will run like.

When you are looking at Crower SFT cams keep in mind most are more symmetrical lobe designs. Ultradyne does not have a lash ramp on the opening side of the lobe, Crower has a lash ramp on both the opening and closing. For a Crower and Ultradyne SFT to peak at the same RPM the Ultradyne needs about 5*@.050” less duration. But the Crower will pack more power into a narrower RPM band if the Ultradyne and Crower have the same LSA’s, which can be good or bad. They are two cam companies are not super easy to compare when look at the specs. Those changes Lee was talking about on his old 247* Ultradyne with the wider LSA and less duration on the intake would be closer to a RA 4 cam with more power and TQ, I would expect that would have screamed in his old Firebird.


The 60311 is bigger than a RA4 cam, they are really not equivalent. The 60311 is hit and miss for vaccuum brakes versus an RA4 cam on an A body unless it has more compression. A RA 4 cam needs a 1.7 rocker arm to run with a 60311 with 1.5s for equivalent peak power. But even with a 1.5 the 60311 will still set the tq peak about 500 RPM higher. It could probably be advanced and lashed loose and get closer, but it will be a compromise somewhere.

When 1.7s are used on the 60311 it will out power the RA4 cams with bigger rockers by 10 or 15 HP, probably more if you had a lot of head flow. The max power would be the nearly same RPM at about 5600. After 5500 the 60311 will carry the power almost to 6000, the RA4 falls off like a rock after 5500. With a 1.5 rocker and a fairly stock round port aluminum head the 60311 will make about 500-510 HP @ 5500 and 530 ft*lbs @ 4300. A cam like typical RA4 cam will make the same HP numbers 500-510 HP but it takes bigger rocker arm ratio like a 1.7 and tq is quite a bit lower, 3600 to 3800. The 60311 likes deeper gears that keep the RPM’a up, can also move the cam timing around and tighten the intake lash at run a fair amount more compression than the RA 4 cams.

Edit: Sorry, I had the wrong dyno file down loaded. I will see if I can find the correct one.

[Skippy597]

Wow Jay THAT is some incredibly useful info! Thank you! I will report back on the timing events reported from crower. They said they can grind whatever I want, but I don't really know what I want. But I feel the guy I been talking to is getting tired of dealing with me lol.

[Steve C.]

My apologies on posting the link for the CAM & VALVE TIMING TAGS.

Brain fade on my part, I thought you had the cam grind number.


.

[Skippy597]

All good Steve. I tired the number they gave me but it didn't populate anything.

Should I have the cam ground +4?

[Skippy597]

Here it is

[Skippy597]

Seems like a good grind, with faster lobes compared to the 60311

[Skippy597]

I think it's gonna be perfect. I'm really excited for it!

[Skippy597]

Jay do you think it would be worth it to go to a 110 lsa to help the mid range or just leave it at the 112 to help with vacuum.

[Jay S]

I’d leave the LSA at 112.

[Skippy597]

Ok good because I already ordered it but the mind wonders. Thanks Jay

[blueghoast]

Originally Posted by Skippy597

Ok good because I already ordered it but the mind wonders. Thanks Jay

It will still rev quick and carry that power for a longer time
Where the tighter LSA will peak faster
By seat of the pants you'll never know the differance.

GT

[Stan Weiss]

Jay,
I am not sure how these stack up, but Ultra Dyne had some very aggressive solid flat tappet lobes with 0.020" to 0.050" in the high 20 degree range in the NF series.

Stan

[Jay S]

Originally Posted by Stan Weiss

Jay,
I am not sure how these stack up, but Ultra Dyne had some very aggressive solid flat tappet lobes with 0.020" to 0.050" in the high 20 degree range in the NF series.

Stan

That is a good example of what I was referring to deciphering mechanical cam cards that stick with the .020” rating. Those NF series cams from Ultradyne used a .0106” lash ramp design instead of the normal .0176” designs. They have a lash setting of .016”, but the duration is rated at .020” tappet. With the shorter ramp design the valve is starting to opening before the cam hits .020” tappet, and will have more seat timing than what the cam card lists. I don’t know for sure if Crower does the same thing on their mechanical cams.