View Full Version : Cam suggestion/recommendation
Tiny Aug 28th, 08, 02:33 PM After much debating, I have decided that the cam I have in my motor now is way to wrong to try to fix. I have decided I am not building a race motor, I am looking for dependability and decent mileage. I will looking to install an overdrive tranny before too long to better enjoy the car.
I am leaning now towards keeping my heads (461s), and leaving the compression ratio alone (9.5:1), and putting in a cam to match the motor (355) as it is now, and get rid of the cam in there now. The tranny is a TH350 with a 2500 stall. The rear is a 8.5: with 4.11s. Rear tire is a 255/60/15 that is 27" tall. I am looking at the Comp XE274H cam. It looks like it will make respectable power, get off the line much better, and work with the combo I have now. 375 hp with 420 ftlbs. Enough for a Nova that I want to enjoy, and not be wrenching on all the time. Does this look like a good cam? 230/236 @ .050 with a .490" lift. That is including 9.5:1 compression and stock 2.02/1.60 heads according to Comp's CamFinder.
I think this would be a much better fit for my car. I am not interested in having a huge dollar motor, nor am I in need of that. I go to the track 1-2 times a year, and the car is most of the time at some local cruise ins. I have pulled my head out of the clouds, and would like the motor to have a nice idle, pull well from a standing start, and will run out of steam about 55-5800 RPMs. And that cam should work well with the 2500 stall I have now.
I know I have been a pita with this , but I am confused and now want to sort this out. I think the right cam will bring this motor alive again, and return the car to being something fun to drive. If you could, please let me know your thoughts. They are most appreciated.
Tiny
Veno Aug 28th, 08, 04:49 PM IMO it would be a good combo... tho the gears would be a little tough to take... 3.42 would be better in over all combonation
Big Dave Aug 28th, 08, 05:01 PM With the OD tranny the 4.11:1 drops down to a 2.87:1, much better for mileage. I run a 236 duration in my 406, but I have 50 more cubes than you. I would think more around 215-220 duration at 0.050" lift to get more bottom end. I am also running a 700R4 with 3.73:1 rear gears. Gets maybe 18 mpg with a strong tail wind rolling down hill.
Big Dave
jim454 Aug 29th, 08, 05:33 PM I would drop down 1 power level to the 268/280 cam, R.P.M. range is 1600-5800/perfect for your application. Lift is .477/.488, not to hard on the valvetrain. 4:11 gears are a little low for cruising . A 3.73 rear gear should help. It should still give you a descent take-off and drop your tach. down a little.
PDQ 71 Aug 30th, 08, 01:35 PM I will let you know that if you think the 268 cam is too mild, IT IS NOT! I put the COMP Extreme Energy 268/280 in my sons 350 we put in his GMC pickup because I thought it would be a pretty mild cam for him, but when we fired it up, I was VERY impressed as the 268 has a very nice lopy idle and actually sounds pretty BAD! I was quite surprised. Has a great sound and makes good power. Me personally I'd go with the 274 that you are thinking of, but the 268 rocks too!
Tiny Aug 30th, 08, 05:14 PM Someone on another board was looking at cams, and pointed me in this direction. This is the 274 cam I was looking at. http://www.compcams.com/Technical/DynoSheets/XE274H-10_001.asp. Looks to pull pretty strong until about 5800 RPMs. That is what I am looking for. And to have over 350 ftlbs of torque at 2500, where the converter stalls at, would be a good launch as well. I am nervous, as I am getting tired of yanking the motor. Pretty soon I will bite the bullet, and get the cam. If there is one that would do as good or better please let me know.
Thanks again,
Tiny
Big Dave Aug 30th, 08, 07:25 PM That is why I bought a three piece timing chain cover. Half hour or so to yank the intake and drop the water pump; and the cam is out and a different grind back in.
http://i45.photobucket.com/albums/f63/3454545/DSC02849.jpg
Big Dave
PDQ 71 Aug 30th, 08, 11:17 PM Dave where'd ya get that fancy balancer bolt and what kind of valve cover gaskets are you using there? Just a couple of things I noticed. NICE Motor!
Tiny Aug 31st, 08, 11:30 AM I am now looking between the Lunati 60102 and the 60103. I really want a 108-110 LSA, and the 60103 has 110, with the 60102 having 112. What will be the difference in idle, will both be lopey? Again, I am looking for power from 1600-5800 RPMs. I think one of these two will be going in shortly.
Tiny
Big Dave Aug 31st, 08, 06:53 PM Dave where'd ya get that fancy balancer bolt and what kind of valve cover gaskets are you using there? Just a couple of things I noticed. NICE Motor!
ARP makes the balancer bolt. Moroso makes the thick rubber steel core reusable valve cover gasket.
Big Dave
PDQ 71 Aug 31st, 08, 11:09 PM Very nice. Have to put those 2 items on my list. If the crank has good enough threads on it, looks like you could turn the motor over with that balancer bolt pretty easy.
PDQ 71 Sep 1st, 08, 12:46 AM The Comp Cams XE268 also has 110 LSA. The Voodoo 268/274 made 380HP @ 5500-6200 rpm and 389 lb/ft TQ at 4500. However the TQ was only over 380 from 4000-5000 rpm it was lower at lower RPM's.
The Comp Cams XE268 made slightly less HP at 368 @ 5500 rpm but made 406 lb/ft TQ @ 4000 rpm and was nearly at 400 lb/ft from 2500 - 5000 rpm over a much broader band.
HP/TQ Comparison
RPM Voodoo 268 XE268H XE274H
HP/TQ HP/TQ HP/TQ
2500 161/337 181/381 171/359
3000 199/348 224/392 211/369
3500 246/369 269/403 257/385
4000 292/384 310/406 301/395
4500 333/389 345/403 341/398
5000 366/384 365/384 368/387
5500 380/363 368/351 383/365
6000 380/332 350/306 378/331
TQ is where the REAL power is at, that's why the big blocks stomp the small blocks 9 out of 10 times and why the 383 is such a popular configuration over the 350. You don't get that much more HP out of a 383 over a 350 but you get a TON of TQ.
These stats are from Desktop Dyno and based on 355 SBC with Wedge Heads with mild pocket porting 2.02/1.6, 9.5:1 CR, 750 CFM Carb w/dual plane manifold, small tube headers w/mufflers. Ran the combo with single plane manifold and the Lunati wins on HP but the Comp Cam still wins on overall TQ band throughout the range. Personally I'd take 40-50 lb/ft of TQ over 12 HP any day. When I look at this data it looks to me like the VooDoo doesn't really start turning on any real torque until up around 4000 rpm while the Comp Cam is walking away from 2500 through 5000 rpm where they start to even out and the VooDoo finally has more at the very top from 5500-6000.
Out of curiosity's sake, I ran the next higher VooDoo cam the 276/284 and frankly it's performance with the same engine setup was worse than the 268 VooDoo both in HP and TQ, it wants more compression and likes nitrous though. The Comp Cam's XE274H gives you back some of the HP that the 268 didn't deliver but at a cost of some of the Torque. I went back and added the data from the XE274 so you could compare all 3 together. Didn't bother with the 60102 VooDoo because in my oppinion the 262 is for wimps...........LOL. The XE268 outperforms both the VooDoo 268 and the XE274 until you get to the top of the rpm range but the XE274 still defeats the VooDoo 268 and gets you up to the 5800 rpm range you wanted. Hope this helps you decide.:cool:
Elvis Sep 19th, 08, 11:52 PM Nobody likes any of the "factory" options?
From what I read in Tiny's opening post, I'd say look at an SBC Marine cam (.435/.449 - 212/219 @.050") or an L-82 cam (.453/.453 - 221/221 @ .050").
Both make great power (45HP and 55HP, respectively, from what I have determined), have a fairly wide power band, offer good drivability and will work within the parameters that Tiny set up in his initial post.
IF your local dealership no longer has NOS cams available, there are some aftermarket makers who make those, or maybe you can have a local grinder create one for you.
I would also suggest moving up to 3.42's in the rear end.
The first and second gears on a 700R4 are fairly steep (compared to the other GM offerings), so you don't need quite so much gear in the back of the car.
3.42's, in 4th (OD) become 2.394:1, effective.
With 27" tall tires and a regular ol' torque converter, engine RPM @ 60MPH is just a couple of RPM over 1900.
This is actually more into the lower end of the Marine cam's power range and actually a little under the "meat" of the L-82's power range.
...but then, you probably already know all this (right Tiny?)
Elvis
ovrdrive Sep 20th, 08, 03:50 PM XE274H-10 in my car. Just click on the link below my sig for videos. Cam is installed striaght up.
355 10.25 comp ratio 461 heads 1.94 /1.50 stainless steel valves Hyper "U" pistons
200-4R with shift kit 2200-2400 stall convertor
4.11 gears...
I think she will do fine on the street.
Now, where did I put that paint roller and that True Value latex paint at?????
Fireguy8 Sep 28th, 08, 02:38 AM I ran the XE274,[installed straight up], in a 79 Z28 with a 406 Eld Per RPM alum heads,w/1.6 roller rockers. We ran a T-350 with a 2800 stall and 3.73`s. The car was street legal still was original paint Int,PS,PDB,PW,PDL. I had subframe connectors and the good comp traction bars. I drove the Z on the street but not every day. The Z would run consistant 12.40`s to 12.60`s all day and would`ve run a little quicker if it had more gear. My point is that it was a streeable car with that cam and I never had a valvetrain problem but I did break it in acording to the recomendations. :thumbsup:
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