Here is my combo:
454 (bored.030)
TRW-2399F30 .095 dome pistons
"781" oval port heads with 2.19/1.88 valves
Comp Cams 280H hydraulic cam
roller rockers
Performer RPM intake
Performer 800 cfm carb
1.75 to 3" Summit headers to 2.5" exhaust
Summit turbo mufflers
M-21 4 speed
Hurst Comp Plus shifter

Don't know what my compression will ultimately be at this point, but should be in the 9.5:1 range.

I plan to run the car at the track on weekends from time to time and want to make sure I am using the best cam for that purpose. Choppy or rough idle is OK with me. I read where the CC 280H may have a tendency to lay down at the top end but good pull at mid range. Others have told me that I need more cam. Nothing worse than feeling that pull disappear early graemlins/sad.gif . All recommendations are appreciated. :D

Please ... I would like as much input as possible, I may have to rethink my whole combo. :confused:

Some guys have said this combo will barely squeak out 400Hp and others say not even that much. graemlins/sad.gif I am looking for 500Hp+, so what do I need to modify in my combo to achieve that goal?

.060" bore? bigger pistons? bigger cam ? :confused:
Thanks in advance....

I'm running a CC 294S in my 468. It has a nice chop (sounds awesome) with great midrange. I'm not worried about bottom end torque, the cubic inches take scare of that. :D

With the 781's and those pistons, I think 9.5 might be pushing it a bit. CR is probably closer to 9:1.

What kind of cam are you wanting hydro? solid? roller? What kind of rpm range are you looking for? You may be limited on going with a larger camshaft with the CR that you have.

You can mill your heads to help bring up CR. I flat milled my 049's .040" to bring the chamber from 122cc to about 113-114. This was good for .7 to .8 increase in CR.

Look for a cam that is made to help boost cylinder pressure (DCR). I think that Comp Cams XE line of cams are designed to do this.

The new line of Extreme solids look nice. The XS274S might work for your application, maybe even have it custom ground on a 108 deg lobe sep.
Just have to be "very careful" when breaking in these cams (aggressive lobes).

http://www.compcams.com/information/WhatsNew/Press/XTREME.PDF

Originally posted by 71454Chevelle:

What kind of cam are you wanting hydro? solid? roller? What kind of rpm range are you looking for? You may be limited on going with a larger camshaft with the CR that you have.
I was hoping to stay with a hydraulic cam and lifters. Do you think the 292H or XE284H might work well for my application. I could talk to my machinist about milling the head a bit and possibly go to a higher piston dome to bump up the compression...... what do you think :confused: I would like to have a solid 12 second car when finished. Am I in the ballpark ? (besides gears & tires, etc...)Thanks smile.gif

Update......

I just spoke with my machinist and we will CC the heads next week and check piston clearance and at that point he will mill the heads and deck the block to achieve a 10:1 comp ratio (if that is all it will take). Based on a 10:1 CR 454 and looking for a strong 12 second car with the combo stated in the my original post, which hydraulic cam would be the best choice ?
Magnum 292H or the Xtreme Energy XE284H ?
Thanks guys

I don't see rear gear ratio anywhere. What is it or what will it be?

Rear ratio notwithstanding, IMHO you'll want a split pattern cam to be able to rpm the engine a bit better. Again, without knowing rear gear, I would use something along the lines of the Comp 280AH-10. Its a oval track cam, so PLEASE break it in with single springs and then add the inners after a bit. In fact, I'd do with it with any aggressive profile. The 280H doesnt need it though.

The NEW Lunati 280/88 is similar to the Comp oval track cam.

Texas70:What are you running with your current set-up?
I have almost the exact same set up except with closed chamber heads 99cc, and stock size valves and some port work. This motor is going in lighter 3200lb 70Nova. My goal is to run consistent high 12s with this set up before shooting some juice. What do you guys think?

427L88, I need some advice on the rear end gearing. My current 10 bolt will be replaced by a 12-bolt posi unit and that is something else I need advice on.... ;)


Chevyguy8, My current combo (plan) is stated at the top of this thread. I am in the process of changing my plan slightly to lean more toward a strip car (12 second runner) and less weekend cruiser.

John

I have approx the same combo - but I am going to use the Keith Black pistons that allow ~ 10:1+ without decking the block. I will get the # if you want it.

Check with Harold at Lunati He suggested his hydraulic 280/288 cam - which should run strong.

I you ever ned an extra set of hands let me know - My wifes brother lives in Houston in the Heights.

Joe

I would think you could run 12s without a cam change. But if you want it to pull hard to 6000 a split duration cam in the 240@.50 range should get you there. The M-21 is a close ratio gearbox and has a tall first gear (2.2-1). To launch it hard you will need at least a 3.73 out back, a 4.10 would probably work even better.

Stick cars need some gear to launch hard, thats for sure.

I ran a 292Magnum in a 454 w/L2399 pistons but had ported 390 casting heads(100cc) that gave me about 10.25/1 comp. It ran 11.80@115mph in a 3600lb Camaro on pump gas.radical idle but still very streetable.

I don't like to jump on the wiped out lobe bandwagon, but my 406sbc ate a lobe on a XE284.

Thanks everybody for all the feedback and thanks to rpol78 (Ted) for the Desktop Dyno run. If anyone can run this engine with 10:1 compression and the 292H cam, I would appreciate it because I think that is where I am taking this motor. DD run showed 424 HP at 5000rpm amd looking for 500+Hp. Thanks again for the help everybody graemlins/thumbsup.gif

Originally posted by jrb56:
Check with Harold at Lunati He suggested his hydraulic 280/288 cam - which should run strong.
..I can vouch for that cam..works well in my 10.5 to 1 454..see ET in signature :D

John, I have a brand new in the box UltraDyne 288/296 .550/.575 cam along with matching springs if you are interested. I had intended to use this cam with my combo but went with a hydraulic roller instead. It might be too much for your combo though.
Email me at mhansford@qx.net if interested.

SilverSS454..........you have mail. graemlins/thumbsup.gif

texas 70 i my self cant help you with a big block much but one off the men here lead you right before you buy at least call lunati and talk to harold i have ben on this board for awhile now and his cams make horse power and torke from all the post i have read there are plenty of men running well in the tens . go solid

that combo is nearly the same as the one in my car. with the cam exception. my car dyn'd at 425hp (340 at the rear wheels) with 781's rpm intake etc. basicly the same.. THAT'S why im building a 502 smile.gif

Texas, you will have 12's with 400 hp. My 71 Cutlass has a 468, will run on reg but likes premium, dead stock 390 heads, stupid TRW forged replacement slugs {forged out of lead}, single pattern Engle cam 238 duration, and 540 lift, a super holeshot and 4:11 gears. Old Weiand dual plane and a fancy-dancy 850 double pumper with a Jacobs prostreet. 12.60's at 104 {see, low hp, or too much gear} with ET Streets, and 1.70 60 foots. Nuthin fancy here. Needs more compression, way more breathing, to go 11's.