Pick me a cam (most loaded question ever!)

496 RB, 9.65:1, 24cc dish, .051 quench distance, Eddie RPM's ported to a bit over 300 cfm. Eddie ProFlo4 XT intake, TTI headers with side dump Boom-Tube exhaust. 1.5 ratio rockers (Comp Pro-Magnums) . 3700#.

Current cam is a Comp solid flat, custom spec'd by Brian at IMM in Indio when I was primarily doing the Silver State stuff.. I don't have the exact specs, but it's about .375 - 380 lobe, .610-ish before lash w/1.6's, .555 measured w/1.5's after lash at the valve. Chevy lobes for the easier ramps. 114° LSA. Current springs are COMP 928's, good to about .630 lift with a solid flat. When the cam was spec'd, I was still running 1.6 rockers and a carb. I melted a Crane Gold during Silver State, so I went to the Pro-Magnums, but they are only made in 1.5.

I want to be at the best compromise between the 2 types or racing I do, and account for the 1.5 rockers The engine made 604/647 with the old cam and rockers and ran low 11's consistently. I think it cold handle a bit more cam to focus on the 4500 - 6000 range. The compression is lower than I want, but there isn't much I can do with the combo as it sets except dropping the gasket thickness down to net .040 quench, but it only gains me 0.19 compression.

Needs to be able to:
Silver State Classic Challenge: high speed road stuff, 90 miles at 145 - 165 MPH, 4500 - 5000 RPM
2500 stall tight converter, 2.50 rear gears in a Mopar dimensioned Ford 9"
Rocky Mountain Race Week (Drag-n-Drive, 1400 miles in the mountains and plains, 5 tracks)
5000 stall 8" converter, 4.10's in a Dana 60

are you thinking of switching to a roller cam or do you want to stay with a flat tappet?

I have two suggestions first buy yourself a good engine program, I like performance trends, but there are others. I design every engine on the program, and it has served me well. It predicts a bunch of stuff like idle vacuum, cranking compression, lets you run different octane fuels, and generates a timing curve. If you take the time to input good numbers it gives accurate results. Second, I would get a cam recommendation from Jones cams, he got me several hundredths from my race car, when the last cam slowed it down. http://jonescams.com/

I would love to go roller, but it isn't in the budget. I'm in the middle of building a shop and now an unscheduled block replacement for the 496, hopefully in time for Rocky Mountain Race Week 2.0 in early September. I split #5, 2" crack running parallel to the deck about 1/2" down in the outboard quarter of the cylinder. I'm having a replacement block machined to take my rotating assembly, and figured there's never a better time for a cam swap. A roller would need a cam, lifters, springs, button, and oil pump drive at minimum. Probably about $2k all said and done.

I'm really looking to see if there is much to be gained in the 4500-6000 range by adding lift, duration, or going to a different LSA.

Whats the duration of the cam in it now ?

So, which one is more important? It can't be "right" for both, only a compromise that's less than ideal for either config.

Compromise... the worst of both worlds.

Right up there with "A camel is a horse designed by a committee"

I "THINK" it is Comp's lobe 6333/6334, which would be:

299°/303° rated duration,
268°/272° @ .050 and
.380"/.384" lobe lift.

With 1.5's that's .570/.576 at zero lash, matching my .555 measures after lash on the intake. That means it was .608/.614 with 1.6's @ zero lash

I'll check the specs when I can get home to the cam tonight. Custom ground, and the lobe #s are on the end.

Call Bullet and get away from using the Chevy lobes on Mopar size lifters That is, really DUMB

I think he needs a very mild lobe, I would get a circle track type lobe for the kind of racing he does.

According to Brian, the reasoning behind the Chevy lobe was the less aggressive valvetrain motion to handle the sustained time at RPM. Not just RPM, loaded RPM. Closer to circle track than road race or autocross.

How much of a difference is there to be had playing with LSA to optimize the 4500-6000 range? I do feel inclined to get back up to the .600 lift line with the 1.5's, but there is a healthy increase in duration that comes along with that. I'd be at 280° @ .050. to get .590".

Mopar Lobes:

#6587: Adv. 289°, 263° @ .050, Lobe lift .404, Lift w/ @ 1.5 .606
#6588: Adv. 293°, 267° @ .050, Lobe lift .411, Lift w/ @ 1.5 .617

Interesting thing I just noticed: My current 6333 with a 1.6 has .608" with 268° @ .050. Almost the same as the Mopar lobes with 1.5's.

The cam you have has enough duration , but I would look at 106 to108 lsa & keep the mild lobe, it will work !!!!! we always ran 106ish lsa in our Sprint cars for that coming off the corner power band, it will like the tighter lsa

lobe 7160 and 7162 on 110°

So is this the cam you have ?

Call Dwayne

yes, on 110° LSA

either keep the same lobe you have & ground on 106 lsa or the 7161 & 7163 on a 108 lsa, other than my advice talk to Dwayne Porter, he can also sell you what you need

Do your Comp Pro-Magnums have bushings installed? If you melted the Crane Gold (aluminum) rockers, I would be worried that the stainless steel will gull to the rocker shaft?
You might want to look at modifications to get more oil to the top end (rockers, pushrods, and springs) when running the Silver State Classic.
Do you need a new cam? The cam you have seems to be designed for endurance and sustained high RPM.
For the drag racing, a more agressive cam profile and timing would add power, but be harder on the valve train.
A valve cover oil spray bar for the springs and rockers might be a good idea?

The Pro-Magnums are bushed with a teflon/composite looking bushing, The Crane golds are not.

NEED a new cam, no. It was, however, picked when I was still running 1.6 ratio rockers. I've lost a fair bit of lift going down to the 1.5's and I would like it back.

I'll be giving Dwayne a call.