454 Comp cam, anybody try?

[fredfryguy]

I have a 71, 454, 4spd I wish to keep in stock appearing condition. I've been told the motor has weak valve springs which carbons up the plug in #6 cylinder. Since I will be replacing the valve springs I may as well spring for a new cam and roller rocker arms. Comp Cam recommends the XE256H-10 or theXE 268 cam. Anybody have any experience with either? I want to maintain the stock intake and exhaust manifold's and carb.

 

[Stallion]

Wow! Nice Vette. I was just wondering, did those side pipes come as original? I've been seeing them around, but I didn't know if they were on the original Vettes. Do side pipes just sound nice, or are they for performance (hp+) too?

Thanks!

TR

 

[fredfryguy]

Reply to TR

No they were not stock on 1971, only on 1969 or 68?! I don't know if they enhance perforance but they do sound bad! They were on me 71 when I bought the car and I love them.Thanks, Fred

 

[MoeJr]

Save yourself a few bucks and buy a cam kit from Summit Racing. Their part#SUM-K1301 is only 82.95 and comes as a kit with lifters. Specs are 218/228 Dur@.050 Lift of .500/.500 and 114 Lobe Seperation Angle. Also you should do a timing chain while you are in there. Just my .02

 

[Stallion]

What kind lifters do they come with? Hydraulic or Mechanical? Probably mechanical for a 454, right?

 

[Jack]

Save yourself a few bucks and buy a cam kit from Summit Racing. Their part#SUM-K1301 is only 82.95 and comes as a kit with lifters. Specs are 218/228 Dur@.050 Lift of .500/.500 and 114 Lobe Seperation Angle. Also you should do a timing chain while you are in there. Just my .02

;stupid I AGREE
Also Blue Racer cams (Crane's bastard son formerly known as "wolverine") can be had for small $. Here's two examples of blue racers for a BBC:
http://www.blueracer.cranecams.com/chevybb.htm
WG-1130 (Cam only, kit available)
grind 280-2H
218 228 @ 0.050"
.500” .500”
lsa 109/119

WG-1081 (Cam only, kit available)
grind 290-2H
228 238 @ 0.050"
.540” .540”
lsa 109/119

All cams mentioned thus far in this thread are for hydraulic flat tappets (lifters). Also DANA-Clevite-Perfect Circle ... AND ... Federal Mogul-Sealed Power-SpeedPro ... both mfgs have nice selection of quality performance cams at bargain prices.
JACK:gap

 

[GWHITE75]

You will need to decide on the type of roller rockers you want, probably roller tip rockers, if you want them to fit under your stock valve covers. Also, you might check a GM site, such as this one - https://www.spoperformanceparts.com/ to find similar cams, springs and lifters. I agree with the timing chain replacement. You did not mention the mileage on the motor and if it is high mileage, freshening up the top end and adding a different cam could bring up other issues like ring sealing and blow by.

 

[fredfryguy]

gwhite 75

Thanks for the feedback. I was told the engine was rebuilt and I am suppose to get the paperwork on it. After I get that I'll be able to determine how far I will be able to go. In the interim I welcome all suggestions! How do you like the 6 speed? Thanks, Fred

 

[sscam69]

I just installed the XE-268H in my SB 355.

The car definitely sounds like it has a cam in it and the performance is there to. I could be just my setup but the car DOES NOT like the 3.08's in the rear. When I did the cam swap I knew I was going to swap the 3.08 for a 3.8 I have already. You might want to take that into consideration before you change out that cam.

With some better heads and higher compression on an SB i know you can make 400+hp/400+ftlbs with that cam.

Dunno about a BB though. Jack or some of these other fellows might chime in on what they think or know.

Frank

 

[GWHITE75]

fredfryguy If it has been recently rebuilt, then you should be okay. Different cams have different cylinder pressures, but you should be able to put one in with a little more agressive profile.

The six speed is great. It was originally a 4 speed car, but I ran a couple of automatics in it for a while and really missed shifting. Also, with 3:55 gears, I tach about 2000 rpms at 70 mph and get right at 14 mpg with the A/C on.

 

[fredfryguy]

3.70 rear

For those who asked the car has 3.70 rear end. Great acceleration and decent milage, 12 mpg kicking it frequently! That always put a smile on my face:L
gwhite75- What kind of increase in power do you think I would get with the mod's of a 268 cam, timing chain and gear, new valve springs and roller tip rockers? Stock the car is 454, 365hp, 4speed with 3.70 rear?
Keep the comments coming! the fryguy

 

[GWHITE75]

I have run several comp cams in my motors, but not the ones you ask about. Hopefully someone has and will respond. I know that I have relied on the techs at Comp Cam to steer me right when choosing a cam for my applications and they have been pretty accurate in their assessments.

If I told you I ran the same cam as you and we both have the same combinations in our drive trains, there would still be some differences in our opinions of its performance, without dyno sheets to confirm. The 256 and 268 are pretty mild cams, so you could expect to pick up some horsepower. How much depends on your heads, compression and tune up.

Do you know anyone with any engine building software? Although I have not used them, I have a friend using one and claims the new stuff is pretty accurate. His motor dynoed at 881 HP and the desk top dyno hardware showed it should make 895 HP. If you have a friend with the software, you could baseline it with your current set up, then install several cams to see what you might expect from the different cams.

One thing I wonder about though is the carbon on #6. It could also be rings or cylinder scoring causing the problem. How did the person determine it was springs?

 

[MoeJr]

I have Performance Trends Engine Analyzer and Drag Racing Analyzer. If you give me your current engines specs and what u wanna do I can run it up and give you both Groos and Net HP and TQ numbers. The 365 HP of your engine is Gross so net is some where around 320 with 4spd less with Automatic.

 

[fredfryguy]

I have run several comp cams in my motors, but not the ones you ask about. Hopefully someone has and will respond. I know that I have relied on the techs at Comp Cam to steer me right when choosing a cam for my applications and they have been pretty accurate in their assessments.

If I told you I ran the same cam as you and we both have the same combinations in our drive trains, there would still be some differences in our opinions of its performance, without dyno sheets to confirm. The 256 and 268 are pretty mild cams, so you could expect to pick up some horsepower. How much depends on your heads, compression and tune up.

Do you know anyone with any engine building software? Although I have not used them, I have a friend using one and claims the new stuff is pretty accurate. His motor dynoed at 881 HP and the desk top dyno hardware showed it should make 895 HP. If you have a friend with the software, you could baseline it with your current set up, then install several cams to see what you might expect from the different cams.

One thing I wonder about though is the carbon on #6. It could also be rings or cylinder scoring causing the problem. How did the person determine it was springs?

I asked my vette specialist your question and he said the plug gets fouled with dry carbon- not oily. He pulled the valve cover to see if the spring was broken and it was not. That all I know. The engine was rebuilt completely 90,000 miles ago. Woman own and driven. Thanks, Fred

 

[GWHITE75]

My mistake. You did say carbon and I was thinking oil.

 

[fredfryguy]

Cam being put in!

Hey everyone, The Comp Cam kit 268 grind & roller rockers and MSD6a ignition is being put on this week and should be ready Fri! I'll keep ya'all posted. Fred

 

[sscam69]

 

[fredfryguy]

Bad news turned into good!

Because of a leaky rear main seal we had to drop the engine pan. Found a thin sliver of what looked like a bearing. Pulled the mains and found a main almost spun and chewed up pretty bad! That's the bad. The good is I'll have an engine with new bearings, rings, line bored mains, pistons and cam bearings! Along with the new Comp cam and kit stated above I should have a very strong rebuilt motor! Should be finished Friday. I'll keep ya posted! Fred

 

[GWHITE75]

That's actually great news.

Just a little more money, BUT with this, you will 1. Know how your engine is built. 2. Solve the carbon on #6. 3. Have it balanced and the cam degreed in.

I think you will be really happy you had that leak, in the long run.

 

[fredfryguy]

Your right GWhite 75

Should get the car back tomorrow evening. When I do she will have, in addition to the cam kit, new pistons, rings cam bearings, bearings, water pump,motor mounts, MSD 6A, plus others! Like you said a little more money but a lot more confidence in the motor! Fred :J :J :J